JP2001240767A - Carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon black suitable for using in coloring paint, ink, and resin excellent in extreme blackness, and dispersability. SOLUTION: This carbon black has an average particle diameter of not greater than 25 nm, a ratio of standard deviation of particle diameter/the average diameter of not greater than 0.35, a Dmod of not greater than 80 nm, a ratio of D1/2/Dmod of not greater than 0.6, and a ratio of N2 SA (m2/g)/SEM (m2/g) of not greater than 2.8. wherein N2 SA represents nitrogen adsorption specific surface area, and SEM represents EM specific surface area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to paints, inks,
The present invention relates to carbon black used for various coloring purposes such as coloring a resin.

[0002]

2. Description of the Related Art Carbon black is widely used as a pigment, a filler, a reinforcing pigment, and a weather resistance improver.
The process involves introducing an oxygen-containing gas and a fuel in a furnace axis or tangential direction into a first reaction zone of a generally cylindrical carbon black production furnace, and continuously producing a high-temperature combustion gas stream obtained by the combustion. While moving to the second reaction zone installed in the furnace axis direction, the raw material hydrocarbon is introduced into the gas stream to generate carbon black, and the reaction gas is rapidly cooled in the third reaction zone to stop the reaction. Furnace type manufacturing methods are widely known.

[0003] Carbon black used as a colorant in resin coloring, printing inks and paints has blackness, dispersibility,
Excellent in gloss, coloring power, flow characteristics and viscosity characteristics are required. Among coating applications, particularly for automotive topcoat applications, extremely high blackness and gloss are required. Blackness when carbon black is used as a black pigment
It is known that the coloring power greatly depends on the particle size and structure of carbon black, and the smaller the particle size, the higher the blackness. For example, the relationship between blackness and particle size is disclosed in JP-A-50-68992.
However, when incorporated into a vehicle or resin of an ink or paint, the reduction in particle size causes deterioration in dispersibility, fluidity, and viscosity characteristics. In addition, the reduction in the structure is favorable in terms of fluidity and viscosity characteristics, but causes remarkable deterioration in dispersibility.

[0004] There is known a method of oxidizing carbon black with an oxidizing agent to impart a functional group to the particle surface for the purpose of improving dispersibility and fluidity. For example, in some varnish systems of paints and inks, carbon black particles having an acidic functional group on the particle surface are used to improve the dispersibility, dispersion stability and viscosity characteristics of carbon black. JP-B-45-37436 discloses a method of oxidizing carbon black with ozone, and JP-B-46-18368.
The publication discloses an example in which carbon black is oxidized with ozone to improve blackness in an ink system. Japanese Patent Publication No. 45-29754 discloses a method of oxidizing carbon black with nitrogen dioxide gas.
In addition, it is also known to perform oxidation treatment with nitric acid or high-temperature air. However, even if these post-oxidation treatments are performed, dispersibility due to low structure and small particle size,
It is not possible to compensate for all of the deterioration in liquidity.

In particular, ultrafine carbon black having an average particle diameter of 15 nm or less has extremely high blackness, and is used in the field of middle-high-grade paints and middle-high-grade resin colorants. Carbon black of this class is manufactured by HCC (High Color Channel) or MCC (M
manufactured by the furnace method, HCF (High Color Furnace) or MCF (Midiam Color Channel).
Color Furnace).

[0006]

The carbon black having such a small particle size has a very high degree of blackness, and is used for the highest grade paint and the highest grade resin coloring. The carbon black produced by the method described in the above also results in a decrease in blackness and fluidity when the structure is enlarged to improve the dispersibility, and a decrease in the dispersibility and fluidity when the particle size is reduced for higher blackness. It has been found by the present inventors that the reduction occurs. In addition, even if an oxidation treatment is performed to improve the fluidity, the effect of the oxidation is hardly obtained, especially at high shear rate conditions. It was also found to be.

[0007] Further, since ultrafine carbon black of ultrafine particles produced by the channel method is produced in a high-temperature aerobic atmosphere, the surface becomes porous at the time of production, thereby increasing the amount of resin and vehicle adsorbed. Therefore, there is a drawback that the viscosity is increased. On the other hand, for the purpose of improving fluidity, Japanese Patent Publication No. 54-7632 discloses a method in which raw material hydrocarbons are vaporized and supplied into a furnace to obtain an EM average particle diameter (corresponding to an average particle diameter) of 9 nm and EM particles. Diameter standard deviation 5.7 nm,
The ratio of BET specific surface area / SEM (EM specific surface area) is 1.2
5 carbon black, EM average particle diameter 14 nm, EM
It is described that a carbon black having a particle diameter standard deviation of 5.5 nm and a BET specific surface area / SEM ratio of 1.25, in which porosity is suppressed, was obtained by a furnace method, and it had good fluidity.

However, the above-mentioned Japanese Patent Publication No.
The method described in the above publication requires a step of mixing a vaporized hydrocarbon gas having a large volume with a combustion gas in a furnace, and the mixing state becomes non-uniform. The distribution is the standard deviation of EM particle diameter / E
M average particle diameter ratio is 0.37 to 0.63, which is significantly wider than channel black (equivalent ratio of 0.25 to 0.35), etc.
In particular, the smaller the particles expected to have high blackness, the larger the particle size distribution tends to be.As a result, large particles having a low blackness and large particles are mixed, and sufficient jet-blackness is obtained. I knew it wasn't.

In order to improve the blackness without reducing the particle size and reducing the structure, Japanese Patent Application Laid-Open No. 9-235485 discloses a method of sharpening the distribution of agglomerates to reduce blackness without impairing dispersibility and fluidity. A method for increasing the degree is disclosed. However, in the coloring field where particularly high jet-blackness is required, carbon black satisfying all the balances has not been obtained even by using such a carbon black having a sharp aggregate distribution, and the blackness or the fluidity Sacrifice any of the characteristics, such as dispersibility.

[0010]

As described above,
Regarding the relationship between the properties of carbon black and the physical properties of a carbon black-containing composition such as a resin composition, it is an important issue how to satisfy blackness, dispersibility, and fluidity, which are generally reciprocal relationships. I have. Furthermore, once dispersed carbon black must not re-agglomerate. The present invention provides a carbon black which can maintain high blackness, good dispersibility, good flowability, especially at high shear rate conditions, and further prevent aggregation when various carbon black-containing compositions are prepared. The purpose is to obtain.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems. As a result, the average particle diameter, the ratio of the standard deviation of the particle diameter to the average particle diameter, the aggregate diameter and its distribution, and the ratio of N ₂ SA / SEM (hereinafter referred to as “roughness factor”) are set within a predetermined range. The present inventors have found that a carbon black exhibiting high optical aptitude that can solve the above problems can be obtained. That is, according to the present invention, the average particle diameter is 25 nm or less, the ratio of the standard deviation of the particle diameter / the average particle diameter is 0.35 or less, and the D _mod
Is 80 nm or less, the ratio of D _1/2 / D _mod is 0.6 or less, N ₂
Carbon black having a ratio of SA (m ² / g) / SEM (m ² / g) of 2.8 or less (however, N ₂ SA is a nitrogen adsorption specific surface area, S
EM represents EM specific surface area. ) Etc.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The carbon black of the present invention has an average particle diameter of 25 nm or less. More preferably 15 nm or less, particularly preferably 8 to
15 nm. If the particle size exceeds 25 nm, the blackness of the carbon black becomes extremely low, and the "blackness" as a color
It is hardly applicable to the field where the quality of the degree is required.
Further, the average particle diameter is preferably 15 nm or less in paints and the like in the field of high blackness where blackness is regarded as important, and particularly preferably 8 to 15 nm in order to achieve the high blackness targeted by the present invention.

Next, in the present invention, the ratio of standard deviation of particle diameter / average particle diameter is set to 0.35 or less. Even in the case of small particle size carbon blacks, when the particle size distribution is observed, when a large amount of carbon black having a particle size significantly larger than the average particle size is contained, the blackness is remarkably reduced due to the presence of these large particle size carbon blacks. . In order to avoid this, it is necessary to obtain a particle size distribution in which the amount of large-particle size particles which cause a decrease in blackness is extremely low. Specifically, the standard deviation Dσ of the particle size distribution and the average particle size D At least 0.35 or less, more preferably 0.30 or less.
The following sharp particle size distribution is necessary to obtain high blackness. Here, the average particle diameter D indicates the average diameter of the particle diameter determined by electron microscopy, and the standard deviation Dδ of the particle diameter distribution indicates the standard deviation in the particle diameter distribution determined by the electron microscope.

[0014] aggregate size of the carbon black to have a high blackness obtaining in the present invention is D _mod is 80nm
Or less, more preferably 50 nm or less. This indicates that the aggregate diameter is closely related to the blackness and the D _mod is 80 nm.
This is because a carbon black having an agglomerate diameter larger than the above cannot obtain a high blackness required by the present invention. In addition, the distribution of the aggregate diameter has a close influence on the blackness and the dispersibility, and in order to achieve the balance between the blackness and the dispersibility required by the present invention, the half-width D1 _{/ 2} of the maximum frequency Stokes equivalent diameter and the maximum frequency It is necessary to adjust the ratio of the Stokes equivalent diameter D _mod , D _1/2 / D _mod, to 0.6 or less, preferably 0.55 or less. Further, within the scope of the present invention, the ratio of the volume 75% diameter D ₇₅ to D _mod ,
D ₇₅ / D _{m od} is preferably 1.6 or less, particularly preferably 1.3 or less. This has an extremely low content of a large aggregate diameter exceeding 75% by volume, which adversely affects the dispersion.

The carbon black of the present invention further comprises N ₂
The ratio of SA (m ₂ / g) / SEM (m ₂ / g) is 2.8 or less,
More preferably, it is 2.5 or less. The temperature at the time of carbon black production tends to require higher temperature for both the channel method and the furnace method as the particle diameter is smaller, but the channel method with poor heat mixing has the same higher ambient gas temperature because the ambient gas temperature is higher. Even if the carbon black has a particle diameter, the carbon black produced by the channel method becomes a more activated carbon black having a higher specific surface area. Carbon black having an average particle size of 25 nm or less is
The temperature at the time of formation is at least 1200 ° C. At this temperature, the activation reaction of carbon black is rapidly promoted, and the development of the roughness of the carbon black surface cannot be ignored. In particular, when producing carbon black having a particle diameter of 15 nm or less, the ambient gas temperature reaches 1500 ° C. or more, and an activation reaction occurs rapidly during a residence time of about 5 to 20 ms after the carbon black is formed, A significant increase in the specific surface area is observed. When the activation reaction of the carbon black surface progresses and the surface becomes porous, the pores are larger in resin and varnish components than the originally existing smooth surface,
The solvent and the like are adsorbed, so that the free resin, varnish, solvent and the like existing between the carbon black aggregates are reduced, and the viscosity of the dispersion system is significantly increased. Such porosity is caused by the carbon black N ₂ SA / S called roughness factor.
There is a strong correlation with the EM ratio.

The ratio of N ₂ SA / SEM is N ₂ SA and S
The EM is determined and the ratio is calculated. Measurement of N ₂ SA is determined in accordance with ASTM D3037-88. The SEM measurement is calculated by the following equation. SEM = 6000 / (ρ · dA) ρ: Specific gravity of carbon black (calculated as 1.86 g / cm ³ ) dA: Body area particle diameter (nm)

If the ratio of N ₂ SA / SEM of carbon black exceeds 2.8, for example, in a dispersion containing 20% by weight or more of carbon black, the viscosity of the dispersion greatly fluctuates even with a slight change in the amount of carbon black. And it becomes extremely difficult to produce a composition having a stable viscosity.
In addition, in a resin masterbatch or the like containing such carbon black in an amount of 40% by weight or more, kneading torque is significantly increased due to an increase in viscosity at the time of dispersion, making kneading difficult. It is not sufficiently dissolved in the step of dilution into another resin when actually used, resulting in significant deterioration in optical characteristics and strength characteristics, making it unusable for practical use.

In order to suppress the development of roughness, it is important to adjust the reaction stop position so that the residence time from the generation of carbon black to the stop of the reaction is shortened. On the other hand, the time until the reaction is stopped is extremely low in safety because the content of aromatic hydrocarbons has a great effect on the progress of the carbon black carbonization reaction. And the time until the carbon black in the state of aggregation of the generated aromatic hydrocarbon having an extremely high hydrogen content undergoes a dehydrogenation reaction and carbonized due to the temperature. Since the aromatic hydrocarbon content of carbon black is increased and the safety is inferior,
The carbon black reaction is stopped at 1200 ° C. where the activation reaction does not proceed instantaneously at a position near the completion of the carbonization reaction.
Cooling to the following temperature is suitable as a method for achieving both safety and suppression of roughness.

As a result of intensive studies on factors affecting the roughness development of carbon black other than the reaction termination conditions, the development of roughness of carbon black is strongly affected by the particle size distribution of carbon black. That is,
The time required for the formation and carbonization of carbon black, that is, the time when the activation reaction starts after carbonization, greatly varies depending on the particle size of each carbon black. Carbon black having a larger particle diameter requires a longer time for carbonization because the generation start is slower and the temperature around the generated carbon black particles is very close. For this reason, the produced carbon black has a wide particle size distribution, and if a large amount of carbon black having a large particle size is significantly larger than the average particle size, the reaction is stopped until the carbonization of these large particle size carbon blacks is completed. However, the activation of the carbon black having an average particle diameter of less than the average particle diameter, which is much faster in generation and carbonization, is started earlier, and furthermore, the circumference of these small particle diameter carbon blacks is extremely high. The activation reaction proceeds very quickly because of the temperature.

As a result, when the carbon black having a wide particle size distribution and a low content of aromatic hydrocarbons is observed in detail by an electron microscope, the carbon black smaller than the average is in a porous state. For black, the whole particle is “pour”
Found that some of them were observed in the state of being entered. There is almost no carbon black with a large particle size compared to the average particle size with a long carbonization time, and
An extremely sharp carbon black having a particle diameter distribution in which almost no carbon black having a particle diameter smaller than the average particle diameter which is rapidly activated, that is, the ratio of the standard deviation Dσ of the particle diameter in the particle diameter distribution to the average particle diameter D, Dσ / D, is obtained. Carbon black of at least 0.35 or less, more preferably 0.30 or less, is also required to suppress the development of roughness. In order to produce carbon black having such a sharp particle size distribution, carbon black is produced in an environment that provides high mixing properties under the conditions of extremely uniform temperature distribution and concentration distribution of the raw material hydrocarbon.

As described above, in some varnishes of paints and inks, the carbon black surface is oxidized to improve the dispersibility to introduce acidic functional groups. However, carbon varnishes having many acidic functional groups on these surfaces are used. Black absorbs the functional groups and polar atom parts of relatively low molecular weight varnishes such as inks and paints to form a varnish phase on the carbon black surface, thereby changing the refractive index of light or solidifying it. This has the effect of preventing aggregation of carbon black and improving optical suitability. In such varnish systems, particularly in some inks and paint varnish systems in which a strongly polar polymerizable low molecular resin component such as an alkyd resin or a melamine resin or a phenol resin is dissolved in a solvent, small particles having high cohesiveness are used. When the carbon black is not provided with an acidic functional unit on the carbon black surface, the blackness and gloss decrease due to an extreme increase in viscosity and re-agglomeration of the carbon black during varnish hardening occur, and the carbon black cannot withstand practical use. It is necessary to use the following acidic carbon black. Therefore, in order to use the carbon black of the present invention suitably for such applications, the pH is adjusted to 5 or less.

Further, regarding the dispersion system in which it is effective to adsorb such a polar varnish component, the surface properties of the small particle size carbon black and the suitability of the dispersed system were examined. The suitability was found to be affected by the balance between the varnish adsorption capacity and the cohesiveness of the carbon black. More specifically, the amount of the acidic functional group represented by the amount of volatiles has a strong influence on the varnish adsorption capacity, and the varnish always enters between the carbon blacks due to this adsorption, so that the carbon blacks approach each other. In addition to the action of inhibiting and preventing aggregation, it is important to control the aggregation property of the carbon black itself, and the aggregation property is a force that attracts active points to inorganic substances that are proportional to the iodine adsorption amount of the carbon black. Carbon black having a lower iodine adsorption amount per unit surface area tends to be less likely to aggregate and have a lower viscosity. The balance between the two is as follows: iodine adsorption amount (IA (mg / g)) / nitrogen adsorption ratio The ratio of the surface area (N ₂ SA (m ² / g)) is 0.5 mg / m ² or less, and IA (mg / g) <volatile content (mg) + 0.1 × N ₂ SA (m ² / g) Aggregation occurs in adsorptive varnish when satisfying the relationship No aptitude is very good.

The surface properties of carbon black such as IA, N ₂ SA and volatiles are balanced as described above, and the development of roughness due to the oxidizing agent during the oxidation reaction is suppressed to form N ₂ S.
As a method of performing the surface oxidation treatment so that A / SEM and Dσ / D fall within the above ranges, the oxidation temperature is usually set to 50
After adjusting the temperature to between 200 ° C and 200 ° C, the nitric acid gas and carbon black were contact-reacted for a short period of time of about 10 to 600 seconds in a reactor capable of giving high mixing properties, and then the temperature was quickly raised. A method of lowering or separating from a gas containing nitric acid and nitrogen dioxide is extremely effective.

The carbon black of the present invention can be made more optically suitable in various dispersion systems by setting the particle size, particle size distribution, aggregate size, aggregate distribution, and N ₂ SA / SEM ratio to specific ranges. A carbon black-containing composition having an excellent balance of dispersibility, dispersion stability, and viscosity can be obtained. In addition, the IA / N ₂ SA ratio, pH, and cD
By setting BP to a specific range, it is possible to obtain a carbon black-containing composition in which these specific balances are extremely excellent. Here, compression D of carbon black
The BP oil absorption (cDBP) affects the cohesiveness of carbon black, and the lower the cDBP, the greater the cohesiveness of carbon black. The effect of the present invention is to improve the cohesiveness by modifying the surface properties of carbon black. Even if it does, sufficient effects may not be obtained. Therefore, the carbon black cDBP suitable for the present invention is at least 50.
It is desirably at least 100 ml / 100 g.

Although the method for obtaining the carbon black of the present invention described above is not limited, preferably, a process for producing a base carbon black which has not been sufficiently oxidized, and a method using the carbon black produced there as a base. It is preferable to use a two-stage manufacturing process including an oxidation process of performing an oxidation treatment while controlling the surface properties to impart volatile components.

As a method for producing carbon black having a small particle diameter, a sharp particle diameter distribution, a small aggregate diameter and a sharp aggregate hair distribution required in the present invention, furnace black and channels produced by known production equipment can be used. Although black and the like can be used, channel black is manufactured in a high-temperature combustion gas containing oxygen, so it is extremely difficult to suppress roughness. Is more preferred. As a method for efficiently producing carbon black having a high blackness and a small particle diameter by a furnace method, the following method can be typically exemplified.

FIG. 1 is a schematic longitudinal sectional view of an essential part of an example of a carbon black production furnace that can be used in the present invention.
The furnace has a first reaction zone 1 for forming a high-temperature combustion gas stream in a longitudinal direction, and a second reaction zone having a choke section for mixing a raw material hydrocarbon with the obtained high-temperature combustion gas stream to produce carbon black. 2 and a third reaction zone 3 downstream of the second reaction zone to stop the reaction. The process itself in each reaction zone can basically adopt the same method as in the prior art. In the first reaction zone, fuel hydrocarbons and an oxygen-containing gas are generally introduced from the combustion nozzle 5 to generate a high-temperature gas stream. As the oxygen-containing gas, air, oxygen or a mixture thereof is generally used. As the fuel hydrocarbon, hydrogen, carbon monoxide, natural gas, petroleum gas and petroleum-based liquid fuels such as heavy oil, coal-based fuels such as creosote oil are generally used. Liquid fuel is used.

In the second reaction zone, the raw hydrocarbon is spray-injected from the raw hydrocarbon introduction nozzle 6 provided in parallel or in the horizontal direction with the high-temperature gas stream obtained in the first reaction zone, and the raw hydrocarbon is thermally decomposed. To convert it to carbon black. As raw material hydrocarbons, generally, benzene, toluene, xylene,
Aromatic hydrocarbons such as naphthalene and anthracene; coal-based hydrocarbons such as creosote oil and carboxylic acid oil; heavy oils such as ethylene heavy-end oil and FCC oil;
Acetylene unsaturated hydrocarbons, ethylene hydrocarbons, and aliphatic saturated hydrocarbons such as pentane and hexane are preferably used. In the third reaction zone, a high-temperature
A liquid or gaseous cooling medium such as water is sprayed from the reaction stopping fluid introduction nozzle 7 to cool the mixture to 800 ° C. or less. The cooled carbon black can be subjected to a known general process such as separation and recovery from gas by a collecting bag filter or the like.

In order to finally obtain the carbon black of the present invention having high jet-blackness, in the production of carbon black using the above-mentioned furnace, the furnace interior including the conditions for the position where the raw material hydrocarbons are introduced. It is suitably performed by appropriately adjusting various conditions in the carbon black generation region of the above.

Specifically, the oxygen concentration in the combustion gas at the site where the raw material hydrocarbon is introduced is usually 3 vol% or less,
Preferably, it is 0.05 to 1 vol%. Surprisingly, by reducing the oxygen concentration at the feed hydrocarbon introduction position as much as possible, carbon black having such a small particle diameter, a small aggregate diameter, and a large particle diameter is suppressed. Good yield can be obtained.

The temperature at the site where the starting hydrocarbon is introduced is 18
The temperature is preferably at least 00 ° C, more preferably at least 1900 ° C, even more preferably at 2000 to 2400 ° C. Thereby, carbon black having a small particle size, a sharp particle size, and an aggregate distribution can be easily obtained. Carbon black agglomerates are formed by thermal decomposition of raw material hydrocarbons, condensation, fusion to droplets, formation of a precursor as a nucleus, and generation of carbon black particles. It is considered to be generated. This reaction proceeds faster at higher temperatures, and the resulting particles are smaller. In addition, it is considered that the carbonization rate is also increased, and the time required for the particles to collide with each other to form an aggregate is shortened, so that the aggregate is also reduced. Therefore, the temperature at the site where the raw material hydrocarbon is introduced is desirably high enough to uniformly vaporize and thermally decompose the raw material hydrocarbon and further to obtain a small particle size carbon black. It is considered that the above-mentioned temperature range is preferable to obtain.

In order to set the temperature of the portion where the raw material hydrocarbon is introduced to the above range, oxygen can be added to air, for example, when forming a high-temperature combustion gas flow in the first reaction zone. Of course, the method of increasing the temperature of the combustion gas is not limited to the addition of oxygen, but it is also possible to adopt a method such as preheating air. The temperature in the furnace can be confirmed by means such as a radiation thermometer. The second reaction zone has a choke. The chalk portion is a portion where the cross-sectional area is sharply reduced. It is particularly desirable that the chalk portion be 500 mm or more, preferably 800 to 3000 mm. Particularly in this range, the diameter of the aggregate of the obtained carbon black can be particularly reduced.

The inlet of the choke portion, which is the start portion of the choke portion, includes the narrowest portion of the flow path, and refers to a portion where the angle of the flow path with respect to the reducing axial direction changes from a value exceeding 5 ° to 5 ° or less. On the other hand, the exit of the choke portion, which is the end of the choke portion, has an angle of 5 ° with respect to the axial direction in which the flow path is reduced.
Refers to the site where the value exceeds. Choke diameter is 170
mm or less is suitable. Particularly preferably 30 to 170 m
m, more preferably 50 to 150 mm. In this range, particularly those having a sharp aggregate distribution can be easily obtained. The faster the gas flow rate in the chalk, the better. After introduction, the raw material hydrocarbon is atomized by the motion and thermal energy of the combustion gas. The speed of the combustion gas at that time is preferably as high as possible, preferably 250 m / s or more, and more preferably 300 to 500 m / s.
s is preferred. In this range, carbon black having a small particle size, a small aggregate, and a narrow particle size distribution can be easily obtained. In order to uniformly disperse the raw material hydrocarbons in the furnace, it is preferable that the raw material hydrocarbons are introduced into the furnace from two or more nozzles.

It is preferable that the supply position of the raw material hydrocarbon be within the choke section and within 1 ms based on the average sectional flow velocity of the combustion gas from the chalk inlet.
More preferably, it is within the range of 0.6 ms. By introducing at this site, carbon black having a small particle diameter and a uniform aggregate diameter can be obtained.

In the case of producing carbon black having a small particle diameter, as described above, since the temperature at the time of producing carbon black is high, the activation reaction of the obtained carbon black proceeds rapidly. Therefore, in order to control the roughness, the reaction stop position should be set appropriately,
In the case of producing carbon black of 14 nm or less, at least at a position corresponding to a residence time of 1 ms to 20 ms from the feedstock supply position, the amount of aromatic hydrocarbons in the carbon black, which is a safety problem, is 1 ppm to 100 p.
pm, the speed of the activation reaction decreases at the position
In order to rapidly cool the reaction gas to 00 ° C. or lower, it is preferable to stop the reaction by uniformly mixing finely sprayed water or an inert gas such as nitrogen and carbon dioxide with the carbon black-containing hot gas. By the combination of these conditions, the aggregate distribution is extremely sharp at a small aggregate diameter,
Further, the generation of aggregates having a large particle diameter can be suppressed, and carbon black having a small particle diameter can be obtained with a good yield by a furnace method.

The carbon black obtained by such a method is used as a matrix, and the oxidation treatment is carried out under the condition that the balance between the amount of iodine adsorbed and the amount of volatiles per unit specific surface area is in a suitable range while suppressing roughness. , N ₂ SA /
The carbon black of the present invention having an SEM specific surface area of 2.8 or less can be obtained. As a method of performing the oxidation treatment satisfying such conditions, the following oxidation treatment is preferable. In addition to providing a large amount of volatile matter, the specific surface area increase that occurs in parallel with the oxidation is suppressed, and the ratio of the N ₂ SA / SEM specific surface area becomes 2.8 after the oxidation treatment.
In order to satisfy the following, more preferably 2.5 or less, and the suppression of the iodine active sites per carbon black surface, the time during which the oxidizing agent and the carbon black coexist at a temperature exceeding 100 ° C. is shortened. In time,
In addition, it is necessary to satisfy the conflicting condition of sufficiently performing a reaction for imparting a necessary volatile component, and in order to achieve this object, an entrained gas flow type oxidation using nitric acid gas as an oxidizing agent as shown below. Preferably, a method is used.

In the entrained gas flow type oxidation method using nitric acid gas as an oxidizing agent, a high-speed gas stream containing nitric acid gas as an oxidizing agent is oxidized under suitable temperature conditions with carbon black, and then mixed with nitrogen oxides. This is a production process in which oxidized carbon black is separated from the oxidized carbon black, and is an oxidation method capable of imparting a high volatile content in a uniform state to obtain carbon black exhibiting good application suitability. More specifically, nitric acid gas is added in an amount of 1 to 30 vol%, more preferably 2 to 15 vol%.
ol% of the oxidizing gas passed through at a flow rate of preferably 3 m / sec or more, more preferably 5 m / sec or more, and carbon black was added before nitric acid in the oxidizing gas was self-decomposed into nitrogen dioxide. Is dispersed, and carbon black is entrained in the gas stream and transported in the reactor. At this time, the ratio between the weight of the nitric acid gas introduced into the unit volume gas and the weight of the carbon black dispersed in the same gas (nitric acid / carbon black ratio) governs the amount of volatiles finally given to the carbon black. It is an important factor. That is, when a large amount of volatile matter is imparted, the volatile matter amount can be adjusted by increasing the nitric acid / carbon black ratio.

The composition of the oxidizing gas constituting the air flow is not limited. In addition to the nitric acid gas, an inert gas such as air or nitrogen and a gas containing water as a raw material and nitric acid or water contained in the air are used. It can also be used. The oxidizing gas is preheated to a temperature at which components such as nitric acid and water vapor do not condense at all, and is kept warm or heated so that the temperature does not decrease during the course, and carbon black is introduced into the oxidizing gas. Since the nitric acid gas rapidly decomposes into nitrogen dioxide as the temperature increases, the temperature of the oxidizing gas until it comes into contact with carbon black is usually 50 to 200 ° C, preferably 50 to 130 ° C. It is.

When the carbon black is collected from the production furnace by a collecting bag or the like, it usually aggregates with each other to form several hundred nm.
It exists in a state of weakly agglomerated to about several mm, and when the oxidation reaction is performed, when introduced into an airflow in such an agglomerated state, sedimentation in the oxidizing apparatus or carbon black on the inner surface of the apparatus is performed. Due to the occurrence of adhesion or the difference in the local concentration of carbon black between the agglomerated portion and the non-agglomerated portion, local uneven nitric acid / carbon black concentration occurs,
This causes the properties of the obtained carbon black to be non-uniform. When using carbon black having a low bulk specific gravity and weak cohesion as a base carbon black to be oxidized, it is sufficiently disintegrated by the energy of the gas stream simply by introducing and mixing the carbon black into the high-speed gas stream described above. Oxidation can be performed in a state of uniform carbon black concentration, but it has a high bulk specific gravity (normally about 0.25 g / cm ³ or more depending on the degree of structure development). When black is used as a matrix, sufficient crushing may not be performed with air current energy of about 3 m / sec to 5 m / sec. Therefore, various kinds of air are used to disperse carbon black in a more suitable state. It is preferable to pulverize in advance using a phase dispersion apparatus or a pulverizer and introduce the pulverized air into a gas stream.

Among the gas-phase dispersing devices and crushing devices capable of achieving the above object, the most compact installation in the device for performing the entrained gas-flow oxidation for obtaining the carbon black of the present invention is preferable. It is possible to further increase the speed of only a part of the airflow in which the carbon black is introduced into the airflow, and to increase the speed by 20 m.
/ Cm2, more preferably at least 50 m / sec, and accelerated by supplying the carbon black thereto, thereby causing the carbon black to collide with the high-speed airflow, thereby utilizing the pressure of the high-speed airflow to increase the crushing energy. An ejector-type dispersing device capable of instantaneously adding water can be mentioned. Such an ejector-type dispersing device is extremely effective not only in compactness but also in carbon black crushing effect.

In this manner, the nitric acid gas is brought into contact with the carbon black by entraining the carbon black in the airflow.
By performing this under the above-described conditions, the carbon black and the nitric acid gas are mixed strongly by the energy of the high-speed airflow. Here, the oxidation reaction with nitric acid is carried out while maintaining the atmosphere at a temperature of 50 ° C. or higher at which the oxidation reaction by nitric acid efficiently occurs and at a temperature of 250 ° C. or lower at which the thermal decomposition of the functional group generated by the oxidation reaction can be suppressed. The reaction is preferably carried out in an entrained gas stream for a period of 10 seconds to 600 seconds required to provide a sufficient amount of a suitable volatile component. In order to obtain carbon black having a high volatile matter / N ₂ SA ratio required in the present invention, the temperature of the oxidation reaction zone is 120 ° C. or more and 200 ° C.
It is more preferable to control at a temperature of ° C. As a device for retaining carbon black in such a predetermined flow rate range while maintaining the temperature in a predetermined range, a double-structure reaction device having an indirect temperature control function as described later can be used. During this reaction, a nitric acid gas may be further added to the gas stream in order to supplement the nitric acid consumed in the initial oxidation reaction.

The carbon black obtained by the above-described oxidation reaction can be converted to an acidic carbon black having a pH of 6 or less, and further, a pH of 5 or less. The pH can be measured according to JIS 6221-1982. After the oxidation reaction described above, the post-reaction gas containing nitrogen oxides such as nitrogen dioxide and nitric oxide, which are by-products of the reaction with nitric acid, is separated from oxidized carbon black. As a method for separating the gas and the oxidized carbon black after the reaction, various methods such as a classifier for classifying the powder by changing the powder transport capacity of a cyclone or the like, and a bag method using a collecting bag can be applied. However, in order to completely separate fine particles from gas, it is desirable to use a bag-type filter. The bag used at this time is preferably made of a furnace cloth made of glass fiber or the like whose surface is reinforced with acid resistance and nitrogen oxide resistance, from the viewpoint of durability.

After a reaction time of 10 to 600 seconds, which is a preferable reaction time in the above-described oxidation treatment, has elapsed, the surface of the carbon black is in a state where highly reactive nitrogen dioxide and unreacted nitric acid are adsorbed on the surface. These substances react with carbon atoms on the carbon black surface while generating heat rapidly as the temperature increases. When oxidized carbon black is collected by a bag-type filter, heat is generated by this reaction because the efficiency of heat release is lower in the trapping part where carbon black is separated and accumulated from the gas compared to the airflow part before reaching it The temperature of the carbon black rises, and the functional groups once attached to the surface are decomposed and desorbed, and the specific surface area increases due to the activation reaction generated by the reaction between the nitrogen oxide and the carbon black at a high temperature. Then, combustion occurs and carbon black disappears.

As a result of examining the cause of such a phenomenon, it was found that the exothermic reaction which causes this phenomenon occurs when the temperature of the carbon black is 110 ° C. or higher, and further rapidly progresses at a temperature of 120 ° C. or higher. . In particular, when the oxidation is performed under the condition that a volatile content is given to carbon black at a high concentration of 7% by weight or more, the temperature is increased to 120 ° C. or more in a state where the oxidized carbon black is accumulated in about 10 to 20 mm or more. Upon reaching the temperature, the temperature of the carbon black rapidly rises in a chain, and quickly reaches 200 ° C. or more, which is a temperature at which the suitability of a part or the whole of the carbon black is hindered.
In order to avoid such a rapid temperature rise, an indirect heat exchange-type temperature controller or a refrigerant gas is directly ejected at the collection bag portion of the bag-type filter where carbon black is deposited. It is desirable to provide a temperature control device and always control the temperature to 120 ° C. or lower, more preferably 100 ° C. or lower by using a manufacturing apparatus capable of controlling the temperature of this portion.

Since carbon oxide oxidized with nitric acid gas by the method described above adsorbs a large amount of nitrogen oxides, the carbon oxide is usually removed in a desorption apparatus at 120 ° C. or higher, more preferably 120 ° C. or higher. 150 ~
Heat to a temperature of 200 ° C., the amount of nitrogen oxides contained is at least 200 ppm or less, more preferably 100 ppm
By maintaining the temperature for 5 to 600 minutes until the temperature becomes below, and removing the nitrogen oxides adsorbed on the surface of the oxidized carbon black, oxidized carbon black containing almost no harmful nitrogen oxides can be obtained. The desorption device used at this time is preferably a desorption device having a structure capable of controlling the temperature within a temperature range of at least 50 ° C. at least above and below a set temperature and having a structure in which carbon black flows and comes into contact with a gas inside the device. . This is to maintain the temperature at a desired temperature at which the nitrogen oxides are sufficiently eliminated and an excessively high temperature which is not desirable for maintaining the physical properties of the carbon black can be prevented.

FIG. 2 shows an apparatus (hereinafter referred to as an entrained gas flow type oxidation reaction apparatus) which can be used in the oxidation treatment for obtaining the carbon black of the present invention and which causes the carbon black to accompany the gas stream to carry out the oxidation reaction. The outline of one example is shown. The entrained gas flow type oxidation reaction apparatus shown in FIG. 2 includes a nitric acid vaporizer, a carbon black supply / dispersion apparatus, a reaction apparatus, a separation apparatus, and a desorption apparatus. Nitric acid vaporizer,
A gas such as air or nitrogen for entraining with carbon black is usually introduced into a cylinder 35 heated by a heater 34 in a state of being preheated to 100 to 150 ° C., supplied by a nitric acid metering pump 36 and sprayed by pressurized spray. Cylinder 35
The gas is finely sprayed into the inside and vaporized to generate a high-pressure gas stream containing nitric acid gas.

In the thus obtained gas stream containing nitric acid gas,
The base carbon black is dispersed in an air stream while being supplied quantitatively by a carbon black supply / dispersion device (30). FIG. 3 shows the details of the carbon black supply / dispersion apparatus. In FIG. 3, reference numeral 311 denotes a hopper, 312 denotes a fixed-quantity feeder comprising an inverter-controlled rotary valve, 313 denotes an ejector, and 314 denotes a gas ejection nozzle. The reaction apparatus includes a thermostat 32 and a pipe (hereinafter, also referred to as a reaction tube) 33 spirally provided therein. Constant temperature bath 32
In order to maintain the air flow accompanying the carbon black in a constant flow rate range and a constant temperature range for a predetermined residence time, the air whose temperature has been adjusted from the atmospheric temperature to 250 ° C. is conducted from the hot air blower 39. Temperature control is possible. The reaction tube 33 is made of stainless steel, is spirally bent, and is set in a constant temperature bath. Thus, the reaction apparatus has a double structure in which the temperature in the reaction tube can be indirectly controlled by adjusting the temperature of the thermostat.

In the apparatus shown in FIG. 2, three reactors are arranged in series, and these can be rearranged. Three
1 is an ejector type disperser, 37 is an air compressor, and 38 is a separation device. The carbon black is introduced into the reaction tube along with the gas flow containing nitric acid gas and undergoes an oxidation reaction. Adjustment of the residence time of the carbon black in the gas stream in the oxidation treatment of the carbon black can be easily adjusted by changing the number of connected reactors. The gas stream containing the carbon black after the oxidation reaction is cooled while continuing to pass through the cooling pipe, and is introduced into a separation device for separating the carbon black and the gas after the oxidation reaction.

The separation device 38 separates the gas stream from the carbon black by collecting the carbon black with the collection bag. The separated carbon black is introduced into a desorption device. FIG. 4 shows a schematic cross section of the desorption device. The desorption device has a cylindrical portion (390) having a heater outside, and an inlet filter (393) installed on the entire lower portion of the cylindrical portion. Heated air is supplied from the heated air supply port (392) through the inlet filter to the cylindrical portion. Introduced within
The carbon black inside the cylinder is in a fluid state, and the contained nitrogen oxides and moisture are desorbed from the carbon black. In FIG. 3, reference numeral 394 denotes an outlet filter, and 395 denotes a gas outlet.

According to the above-described production method, a carbon black having a small particle diameter having various characteristics specified in the present invention can be produced. A high carbon black composition can be obtained.

In order to obtain the coating composition of the present invention, the resin composition of the present invention, the rubber composition of the present invention, and the ink composition of the present invention, except that any one of the carbon blacks of the present invention is contained. A desired composition can be prepared using various known methods. When preparing the resin composition containing the carbon black of the present invention, applicable resins are not particularly limited, for example, various thermoplastic resins or thermosetting resins, various additions such as a mixture of these resins or fillers. An object may be added. Normal,
What is used for preparing the resin composition may be appropriately selected and used according to the purpose.

The carbon black of the present invention is added to these resin components and kneaded if necessary. At this time, those usually used as a resin kneader, for example, a roll mixer as a batch-type open type, a Banbury type mixer as a batch-type closed type, a single-screw kneading extruder as a continuous screw type, a twin-screw kneading extruder, and a continuous rotor As a formula, a single-screw kneader, a twin-screw kneader or the like can also be used. The content of carbon black may also be determined by using a known technique, and is generally preferably 0.1 to 60% by weight.

In preparing the coating composition containing the carbon black of the present invention, the varnish to be used is not particularly limited as long as it can be used for the coating. For example, various oil-based coatings, alcoholic coatings, synthetic resins Paints and water-based paints may be used, and the intended paint is not particularly limited. Oil paints, oil enamels, phenolic or maleic resins, alkyd resin paints, amino alkyd resin paints, urea resin paints, alcohol spirits Paints, lacquers, vinyl resin paints, acrylic resin paints, polyester resin paints, epoxy resin paints, polyurethane resin paints, silicone resin paints, emulsion resin paints, and water-soluble resin paints. The content of carbon black may also be determined by using a known technique.
% By weight is preferred.

The ink composition of the present invention is not particularly limited except that the carbon black of the present invention is used. That is, it is blended with various conventionally known varnishes and solvents, and sufficiently dispersed. The carbon black of the present invention is excellent particularly when used as an aqueous ink composition. For example, a known means such as dispersing in an aqueous medium together with various water-soluble varnishes such as an alkali-soluble resin and a hydrosol-type resin as a varnish may be adopted. The dispersion method is not particularly limited. The dispersion method also uses various known methods,
Various additives may be added.

By preparing the coating composition, resin composition and ink composition containing the above-described carbon black of the present invention, suitable characteristics can be exhibited in these various uses. As described above, the carbon black of the present invention has extremely excellent dispersibility in various vehicles and at the same time has a very high blackness, so that these various compositions also have extremely excellent properties. It is. As described above, the carbon black of the present invention that can obtain an excellent carbon black-containing composition by being blended with various vehicles exhibits a jet-blackness of a level that has not existed before, and is a novel one. Yes, and can be easily obtained, for example, by the manufacturing method described above.

[0056]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The following test methods were used to determine the physical properties of carbon black in each of the examples and comparative examples. (Volatile content) The volatile content was determined according to JIS K 6221-82. (D (average particle diameter), Dδ (standard deviation of particle diameter)) By electron microscopy. Electron microscopy is a method described below. Add carbon black to chloroform and add 200
After irradiating with ultrasonic waves of KHz for 20 minutes to disperse, the dispersed sample is fixed to the support membrane. This is photographed with a transmission electron microscope, and the particle diameter is calculated from the diameter on the photograph and the magnification of the photograph. This operation was performed about 1500 times,
D is obtained by the arithmetic mean of those values, and Dδ is obtained from the distribution of those values.

(N ₂ SA (nitrogen adsorption specific surface area)) N ₂ SA
Was determined according to ASTM D3037-88. (SEM (EM specific surface area)) SEM was calculated from the following equation. SEM = 6000 / (ρ · dA) ρ: Specific gravity of carbon black (calculated as 1.86 g / cm ³ ) dA: Body area particle diameter (nm) (IA (Iodine adsorption amount)) IA is ASTM D-1510
Determined according to -88b

(CDBP) Compressed DBP absorption (cDB
P) was determined according to ASTM D-3493-88. (PH) The method of measuring pH is ASTM D-1512.
84.

(D _mod , D _1/2 ) Maximum frequency Stokes equivalent diameter (D _mod ) and Stokes equivalent diameter _half width (D _1/2 ) were determined as follows. Using a 20% ethanol solution as a spin solution, a Stokes equivalent diameter was measured by a centrifugal sedimentation type flow rate distribution measuring device (DCF3 type manufactured by JL Automation), and the relative occurrence frequency of the Stokes equivalent diameter to a given sample was measured. (FIG. 5). A line (B) is drawn from the peak (A) of the histogram to the X axis in parallel with the Y axis and ends at a point (C) on the X axis of the histogram. The Stokes diameter at point (C) is the maximum frequency Stokes equivalent diameter D _mod . Further, the midpoint (F) of the obtained line (B) is determined, and a line (G) is drawn through the midpoint (F) and parallel to the X axis. The line (G) shows the distribution curve of the histogram and 2
Intersect at points D and E. The absolute value of the difference between the two Stokes diameters at two points D and E of the carbon black particles is the Stokes equivalent diameter _half width D1 _{/ 2} value.

(T%) Toluene coloring power (T%) is AST
Determined according to MD-1618-83. (LDPE masterbatch characteristic test) The characteristic test of the LDPE masterbatch was carried out by the following method. LDPE
The maximum torque at the time of kneading the master batch and the dilution state of the master batch diluted in resin were observed and photographed, and the presence or absence of dilution unevenness was visually compared to evaluate the quality of the dilution state as dilutability. Using a 250 cc Banbury mixer, 50% by weight of the sample carbon black is mixed with the LDPE resin, and the mixture is kneaded at 115 ° C. for 10 minutes. The change in the torque during the kneading is recorded, and the maximum torque is determined. Mixing conditions LDPE resin 101.89 g Calcium stearate 1.39 g Irganox 1010 0.87 g Sample carbon black 104.15 g Next, dilute for 5 minutes with a two-roll mill at 120 ° C. so that the carbon black concentration becomes 1.2% by weight. I do.

Diluting Compound Preparation Conditions LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 50% blended resin 1.5 g A sheet having a slit width of 0.3 mm was cut into chips, which were cut into chips and placed on a hot plate at 240 ° C. for 65 mm. ± 3μm
Into a film. Observe with an optical microscope of 20 times magnification and take a photograph. From this photograph, the amount of black streaks and black particles with a diameter of 50 μm or more by the undiluted master batch was visually compared, and those with almost no undiluted material were rated “5” and those with undiluted streaks remaining. 3. Evaluation is made by comparing five levels with one in which large particles in a lump form remain as one.

(Acrylic paint suitability) Acrylic paint suitability (evaluation of suitability in an acrylic-styrene-melamine-containing paint system) was measured using an acrylic-styrene-produced by Dainippon Paint Co., Ltd.
2.1 g of a sample carbon black and a paint varnish were prepared using a paint varnish containing melamine resin (trade name: “Aclose # 6000 Clear”) and a thinner containing xylene-ethylbenzene (trade name: “acrose thinner”). 14.9 g and 10.0 g of thinner are put together with 90 g of 2.0 mm-diameter glass beads for dispersion in a sealed 140 cc glass bottle. A reference carbon black is used in place of the sample carbon black, and the mixture is placed in a glass bottle with the same composition. These glass bottles were both set in a paint conditioner manufactured by Red Devil Co., Ltd. and dispersed for 240 minutes to prepare dispersion paints. 3.0 g of each of these dispersion paints was collected, and TOKIMEK Co., Ltd. was collected.
The viscosity is measured using an E-type viscometer manufactured by the company. 51.4 g of paint varnish was added to the dispersed paint remaining in each glass bottle.
Further, the mixture was further dispersed for 5 minutes to prepare a paint sample. An appropriate amount of each paint sample was collected, and applied to a smooth PET film by using a 27 mil bar coater so as to form a uniform thickness. Let stand at room temperature in a horizontal position for minutes. After that, this coated PET film is
Place horizontally in a thermostat controlled at 120 ° C ± 10 ° C.
Bake for 0 minutes. Thereafter, the film is taken out of the thermostat and cooled, and the blackness and gloss of each coating film are evaluated by visual judgment. Each determination was performed using carbon black “# 2650” manufactured by Mitsubishi Chemical Corporation as a reference carbon black and DEGU.
Carbon black “FW200” manufactured by SSA was used. Regarding the degree of blackness, “# 2650” was rated 10 points, and “FW200”
With 30 as the reference value, and for the gloss, “# 265
The blackness of each coating film sample obtained using the sample carbon black was evaluated by visual sensation judgment, using 10 as a reference value and “FW200” as 15 points as reference values.

(Example 1, Comparative Examples 1 and 2) A production furnace schematically shown in FIG. 1 (a diameter of a choke portion of 60 mm and a length of a choke portion of 700 mm, and a reaction stop was performed at a diameter of 200 mm installed at the outlet of the choke portion) In the third reaction zone, water was sprayed at a rate of 150 kg / hr at a position 200 mm from the outlet of the chalk portion, and water was sprayed at a rate of 150 kg / hr under the production conditions shown in Table 1. Example 1), carbon black B (comparative example 1) and carbon black C (comparative example 2) were produced. Table 1 shows the physical properties of these carbon blacks.

(Example 2, Comparative Example 3) Using the carbon blacks A and B obtained in Example 1 and Comparative Example 1 as a matrix, respectively, using an entrained gas flow type oxidation reactor schematically shown in FIG. An oxidation treatment was performed under the oxidation conditions shown in -2. The total length from the vaporizer to the carbon black supply / dispersion apparatus was 3 m (residence time: about 0.5 seconds). The ejector for dispersing the carbon black had a nozzle diameter of 2 mm, and the ejection speed was about 300 m / s. In the reaction apparatus shown in FIG. 2, a reaction tube made of stainless steel having an inner diameter of 25 mm and having a total length of 100 m is bent into a spiral shape having a diameter of 1.8 to 2 mm and placed in a reaction tank. The total length of the cooling part piping is 10 m. In the following Examples and Comparative Examples, the residence time was adjusted by changing the number of connected reactors.

After the oxidized carbon black was recovered from the gas stream by the separation device, it was introduced into a desorption device schematically shown in FIG. 4 to desorb nitrogen oxides. The cylindrical part of the desorption device has an inner diameter of 400 mm and a height of 600 mm. In each of the following Examples and Comparative Examples, while the cylinder portion was filled with 1 kg of carbon black, the desorption air preheated to 120 ° C. was introduced at a rate of 100 liters / minute, and the temperature in the apparatus was adjusted to 120 ° C. After preheating for 1 hour, the temperature was raised to 150 ° C. for 1 hour, followed by desorption. After cooling to 30 ° C., the carbon black was taken out, mixed well, and sampled. Was measured, and optical suitability and the like were evaluated. Table 2 shows the physical properties and optical suitability of the obtained oxidized carbon black. In the table, the carbon black concentration refers to the unit entrained gas volume (m ³ ) in the reaction tube.
It shows the weight (g) of carbon black contained per unit. The oxidation temperature indicates the temperature of the entrained gas in the pipe, the oxidation time indicates the average residence time of the carbon black in the reaction tube, and the amount of nitric acid is based on 100 parts by weight of the reacted base carbon black. It is shown in parts by weight of the introduced nitric acid gas.

Comparative Example 4 The physical properties of a commercially available acidic carbon black (“FW200” manufactured by DEGUSSA) are shown in Table 2. Comparing Example 1 with Comparative Examples 1 and 2, it can be seen that PVC blackness is very excellent due to having the particle size distribution defined in the present invention. Further, comparing Example 2 and Comparative Examples 3 and 4, carbon black having high PVC blackness, low masterbatch torque and high masterbatch dilutability, that is, excellent optical aptitude, dispersibility, dispersion stability and viscosity was obtained. Can be prepared.

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

Industrial Applicability The carbon black of the present invention can exhibit excellent suitability in various dispersion systems with better balance of optical suitability, dispersibility, dispersion stability and viscosity, and is extremely industrially effective.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a carbon black production furnace that can be used in the present invention.

FIG. 2 is a schematic view showing an example of an entrained gas flow type oxidizing apparatus that can be used in the present invention.

FIG. 3 is a schematic diagram showing an example of a carbon black dispersion / supply device that can be used in the present invention.

FIG. 4 is a schematic diagram showing an example of a desorption device that can be used in the present invention.

FIG. 5 is a diagram showing a method of _obtaining D _1/2 / D _mod .

[Explanation of symbols]

34 Heater 30 Carbon black supply / dispersion device 311 Hopper 312 Quantitative feeder composed of an inverter-controlled rotary valve 313 Ejector 314 Gas ejection nozzle 390 Cylindrical part (390) with heating heater outside 393 Inlet installed on entire lower part of cylindrical part Filter 394 Outlet filter 395 Gas outlet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 AA001 DA036 GH01 4J037 AA02 BB05 BB15 BB18 BB28 BB33 DD05 DD07 DD17 DD20 EE46 FF05 4J038 EA011 HA026 KA20 4J039 AE02 AE03 AE06 BA04 BE01 CA06 EA19

Claims (8)

[Claims] 1. An average particle diameter of 25 nm or less, a ratio of standard deviation of particle diameter / average particle diameter of 0.35 or less, and a D _mod of 80 n.
m or less, the ratio of D _1/2 / D _mod is 0.6 or less, and N ₂ SA (m ² /
g) A carbon black having a ratio of SEM (m ² / g) of 2.8 or less. (However, N ₂ SA indicates a nitrogen adsorption specific surface area, and SEM indicates an EM specific surface area.) 2. The carbon black according to claim 1, wherein the pH is less than 5. 3. The method according to claim 1, wherein the average particle size is 15 nm or less.
Or the carbon black according to 2. 4. The ratio of IA (mg / g) / N ₂ SA (m ² / g) is 0.
5 mg / m ² or less, and IA (mg / g) <volatile content (mg / g) + 0.1 × N ₂ SA (where IA represents an iodine adsorption amount and N ₂ SA represents a nitrogen adsorption specific surface area). The carbon black according to any one of claims 1 to 3. 5. The carbon black according to claim 1, wherein cDBP is 50 cc / 100 g or more. 6. A coating composition comprising the carbon black according to claim 1. Description: 7. An ink composition comprising the carbon black according to any one of claims 1 to 5. 8. A resin composition containing the carbon black according to any one of claims 1 to 5.