JP2000313821A - Carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a carbon black which has satisfactory blackness and dispersibility and does not agglomerate by selecting a carbon black which has a specified average particle diameter, a specified highest-frequency Stokes equivalent diameter and a specified periphery length fractal dimension of agglomerates and/or a specified anisotropy ratio of agglomerates. SOLUTION: This cabon black has an average particle diameter of 30 nm or lower, a highest-frequency Stokes equivalent diameter (Dmod) of 100 nm or lower and a periphery length fractal dimension of agglomerates of 1.35 or higher and/or an anisotropy ratio of agglomerates of 0.620 or higher, Preferably, the carbon black has a ratio (D1/2/Dmod) of half-value width (D1/2) of highest- frequency Stokes equivalent diameter to Dmod of 0.6 or lower, a ratio (D75/Dmod) of vol. 75% diameter (D75) to Dmod of 1.6 or lower and a specific surface area (N2SA) of 80 m2/g or higher. This carbon black can be produced e.g. by reducing the O2 concentration at the position of feeding a raw material hydrocarbon as low as possible and by raising the temperature high enough in producing a carbon black by mixing the raw material hydrocarbon into a high-temperature combustion gas stream to thermally decompose the hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to carbon black used for various uses such as filling materials, reinforcing materials, conductive materials and coloring pigments.

[0002]

2. Description of the Related Art Carbon black used as a colorant in resin colorants and paints is required to be excellent in blackness, dispersibility, gloss and coloring power, and is mainly used as a reinforcing agent for automobile tires. Carbon black having excellent abrasion resistance is required. These carbon black particles actually exist in the form of agglomerates where the particles are fused together like skewered dumplings, and individual spherical particles characterize the dumplings and the peaks and valleys of the dumplings However, the particle diameter of this as a single particle is usually 10 to 300 nm, which belongs to the so-called aerosol or colloid region. The size of the particle size of the carbon black is closely related to the performance in various applications, for example, the reinforcing property and the blackness, and the blackness / coloring power when the carbon black is used as a black pigment is determined by the carbon black. Dependence on the particle size is large, and the smaller the particle size, the higher the blackness. However, it is also known that the dispersibility and fluidity when blended in the vehicle or resin of the coating material decrease (carbon Black Handbook, 3rd edition, I. General introduction, page 7, JP-A-50-689
No. 92).

[0003] Another factor that greatly affects the application of carbon black to products is the state of carbon black aggregates. The size of the agglomerates greatly affects the tensile stress and extrusion characteristics when compounded with rubber, the dispersibility, blackness and viscosity when compounded with a vehicle and resin of a paint. Carbon black is ultimately composed of aggregates of aggregates of many particles, and controlling the size and shape of these aggregates leads to controlling the properties of carbon black itself. is important.

[0004] In order to examine the effect as an aggregate, the size and distribution of the aggregate as a whole as a single particle are quantified. The size of the aggregate measured by treating the aggregate as particles is expressed as an aggregate diameter. This agglomerate size has a significant effect on the properties of carbon black, and it is clear that many of the properties of carbon black, which were previously thought to be attributed to the particle size, can be better explained by the agglomerate size in some cases. It has become For example, for optical properties such as coloring power and dynamic viscoelastic properties and reinforcing properties of the compounded rubber composition,
It is considered that the aggregate diameter plays a large role, and carbon black having a small aggregate diameter has a remarkable blackness as a colorant, and also has excellent physical properties when used as a rubber composition. Therefore, as a method of reducing the diameter of the aggregate, there has been known a method of adding an alkali metal salt or a solution thereof to a raw material oil or introducing it into a combustion zone or a reaction zone. However, when incorporated into paint vehicles and resins, small aggregate size also results in poor dispersibility and fluidity.

[0005] On the other hand, regarding the aggregate of carbon black, the form thereof is also recognized as representing the characteristics of carbon black. ASTM D-3849 “Standard Test Method for Primary Aggregation Size of Carbon Black from Electron Microscope Image Analysis” describes a method of directly digitizing the form of carbon black aggregates from electron micrographs and numerically analyzing the morphology. . In addition, there is an example in which the morphology of five types of carbon black is classified into nine types from a sphere to a fibrous one using the Feret index, and morphological analysis is performed (Hess, WM, Chirico, VE an
d Deviney, ML: Rubber Chem.Technol., 52, 377 (197
9)). Further, the perimeter fractal dimension of the carbon black aggregate is an index indicating the complexity of the shape of the aggregate form, and becomes 1 for a simple form such as a sphere. Although the value is 2, recently, there has been an example in which the fractal dimension of the carbon black aggregate is obtained and analyzed (CRHerd, GCMcDonald and WM).
Hess, Rubber Chem and Tech. 65,107 (1992), Minoru Hisaeda, Shinji Hayashi, Yusuke Asakuma, Hideyuki Aoki, Takatoshi Miura: Proc. Of the 35th Combustion Symposium, 35,717 (1997)).

However, all of the above reports merely analyze and quantify the morphology of the aggregates of carbon black. For example, various types of carbon black such as blackness and dispersibility when carbon black is used as a black pigment are used. The relationship between the next physical property and the aggregate morphology is not mentioned, and these have not been elucidated yet.

[0007]

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 and dispersibility, which are generally in a reciprocal relationship. An object of the present invention is to provide a carbon black which can maintain high blackness and good dispersibility and prevent aggregation when various carbon black-containing compositions are prepared.

[0008]

Means for Solving the Problems The present inventors have analyzed the dispersion behavior of carbon black in a matrix and the factors affecting blackness, and have found that higher blackness and better dispersibility can be obtained as compared with the prior art. Various studies were conducted to obtain carbon black having the same.
As a result, it has been found that the form of the aggregate of carbon black greatly affects blackness and dispersibility. And
The form of the carbon black aggregate is largely divided, and the form of the aggregate is complicated, or the degree of linearity is larger when the form is linear and linear when spherical and linear. The present inventors have found that carbon black having a particle diameter and a small aggregate diameter has both high blackness and good dispersibility, which were conventionally considered to be trade-offs, and reached the present invention. That is, according to the present invention, the average particle diameter is 30 nm or less, and D _mod is 1
00 nm or less, the perimeter fractal dimension of the aggregate is 1.35 or more, and / or the anisotropic ratio of the aggregate is 0.620.
The following is in carbon black.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Among the requirements for defining the carbon black of the present invention, the greatest feature can be said that the shape of the aggregate is particularly focused on the perimeter fractal dimension and the anisotropic ratio. In the carbon black of the present invention, the perimeter fractal dimension of the aggregate is preferably 1.35 or more, particularly preferably 1.38 or more. The complexity of the aggregate of carbon black can be quantified by using the perimeter fractal dimension of the aggregate obtained by directly analyzing the morphology of the aggregate from an electron micrograph. By image analysis using an electron microscope, the projected area A and perimeter P of each aggregate
Is measured. The measurement procedure is based on ASTM Standard D3849-
87 "Standard Test Method for Carbon Black Primary Aggregation Size from Electron Microscope Image Analysis". The definition of the area A and the perimeter P is defined in section 11 of D-3849. It is stated in the calculation.

A = projected area of carbon black aggregate nm ² P = perimeter of carbon black aggregate nm where projected area A, perimeter P and perimeter fractal dimension Dp are as follows: Have a relationship. Taking the logarithm of P~A ^{Dp / 2} sides, the _{log 10 P = (Dp / 2} ) log 10 A + C. The log ₁₀ P and the log ₁₀ A are plotted on a graph, the data are linearly approximated by the least square method, and Dp is determined from the slope of the straight line. An example of the graph at this time is shown in FIG.

The perimeter fractal dimension of the carbon black aggregate is 1.35 in the conventional product confirmed by the present inventors.
And the dispersibility of the paint in the vehicle, resin and the like is not sufficient as compared with the carbon black of the present invention. The reason why the dispersibility is improved as the perimeter fractal dimension increases is considered as follows. That is, when carbon black having a small particle diameter or an aggregate diameter is blended with a vehicle of ink or paint, a resin, or the like, a state in which the attractive force between the surfaces is strong and the carbon black is hardly dispersed is obtained. At this time, if the fractal dimension is small and the surface of the aggregate has a simple shape, since one aggregate has many portions that can contact other aggregates, the aggregates are further attracted to each other by the attractive force between the surfaces. It is in a state where it easily aggregates. On the other hand, if the fractal dimension is 1.35 or more and the form of the aggregates is complex, even if the aggregates come into contact with each other, the branches of the aggregates hinder the aggregation, and consequently the aggregation Even if the aggregates are close to each other, the number of voids increases, and the aggregates of the aggregates cannot approach each other much. Therefore, it is considered that the dispersibility is improved.

The carbon black of the present invention preferably has an anisotropic ratio of aggregates of 0.620 or less. The meaning of the anisotropic ratio is different from the above-described perimeter fractal dimension, as described below, but is different from the perimeter fractal dimension of 1.35 or more as the carbon black defined in the present invention. A carbon black having both a requirement of a square ratio of 0.620 or less also exists as one embodiment of a preferable carbon black. The anisotropic ratio of carbon black aggregate is a value obtained by dividing the width of one aggregate of carbon black by the maximum length. When this value is close to 0, the form of the aggregate is close to a straight line, and when it is close to 1, the form is a circle. To be closer to
According to ASTM D-3849 “Standard Test Method for Primary Aggregation Size of Carbon Black from Electron Microscope Image Analysis”, this anisotropic ratio was 200,000 × 240 at 150,000 times.
An electron micrograph of a state in which the carbon black aggregate is dispersed in a size of mm is obtained. Then, the electron micrograph is applied to an image analyzer to determine the maximum projection length MDT of each aggregate. When the maximum projection length orthogonal to the maximum projection length MDT is set to the width PPF, the anisotropic ratio WB
L is the value of (PPF / MDT). Obtained aggregate 1
The final anisotropic ratio is determined by averaging the anisotropic ratios for each one. FIG. 1 shows an image of the maximum projection length MDT and the width PPF orthogonal to the MDT.

The anisotropic ratio of the aggregate of carbon black is more than 0.620 in the conventional product confirmed by the present inventors. Compared with the carbon black of the present invention, the vehicle and the resin etc. Dispersibility to the surface is not sufficient. The following are conceivable reasons why the blackness and the dispersibility are improved when the anisotropic ratio is reduced. That is, when carbon black having a small particle size or a small aggregate size is blended in a vehicle of a coating material, a resin, or the like, a surface attraction force is strong and it is difficult to disperse. At this time, when the anisotropic ratio is large and the form of the aggregate is close to a sphere, one aggregate has many portions that can be in contact with other aggregates, so that the aggregates are more likely to aggregate due to surface attraction. State. On the other hand, when the anisotropic ratio is 0.620 or less and the form of the aggregate is a linear form, even if the aggregates contact each other, the linear aggregates prevent the aggregates from each other, As a result, even if the aggregates come close to each other, the number of voids increases, and the aggregates cannot approach each other much. Therefore, it is considered that the dispersibility is improved. In addition, since there is no reaggregation in the vehicle or resin of the paint, the size of the aggregates can be kept small as a result, so that the blackness is considered to be improved.

The carbon black of the present invention having the above-mentioned aggregate shape has an average particle diameter of 30 nm or less and a D _mod of 1
A small particle diameter of less than 00 nm, a small aggregate diameter,
In the above range, the above-mentioned aggregate form exhibits both the blackness and the dispersibility. Further, the average particle size is preferably 30 nm or less, particularly preferably 15 nm or less. If the average particle size exceeds 30 nm, the blackness when used as a black pigment may be insufficient. Also,
D _mod is preferably 80 nm or less, particularly preferably 4 nm.
0 nm or less. If D _mod exceeds 80 nm, the blackness when used as a black pigment may not be sufficient.

Furthermore, the carbon black of the present invention
Therefore, in order to express high blackness and dispersibility,
It is preferable that the cloth is sharp and the
Half-width D of large frequency Stokes equivalent diameter_1/2And maximum frequency strike
Equivalent diameter D_modRatio, D _1/2/ D_modBut preferably
0.60 or less, particularly preferably 0.55 or less. Ma
75% diameter D₇₅And D_modRatio, D₇₅/ D_modBut,
It is preferably at most 1.6, particularly preferably at most 1.3.
You. On the other hand, the carbon black of the present invention has a specific surface area.
N_TwoSA is preferably 80m^Two/ G or more, especially preferred
200m^Two/ G or more. N_TwoSA is too small
That the blackness when used as a black pigment is not sufficient
There is.

The carbon black of the present invention described above has excellent blackness and dispersibility.
More specifically, carbon black having a dispersion index of 1000 or less and a PVC blackness of 25 or more can be used. The methods of measuring these dispersion index and PVC blackness will be described in Examples described later, and those having a small dispersion index indicate that they are promptly dispersed at the time of coating, and those having a high PVC blackness have a high blackness. Indicates that it is excellent.

In order to efficiently obtain the carbon black of the present invention, the following methods are exemplified. FIG. 3 is a schematic vertical sectional view of a main 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 2
It is downstream from the reaction zone and is divided into a third reaction zone 3 for stopping 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, raw material hydrocarbons are spray-injected from the raw material hydrocarbon introduction nozzle 6 provided in parallel or in the horizontal direction with the high-temperature gas flow obtained in the first reaction zone, and the raw material hydrocarbons are thermally decomposed to carbon black. To be converted. The raw material hydrocarbons are generally aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene and anthracene; coal-based hydrocarbons such as creosote oil and carboxylic acid oil; and heavy petroleum oils such as ethylene heavy-end oil and FCC oil. And acetylenically unsaturated hydrocarbons, ethylene hydrocarbons, and aliphatic saturated hydrocarbons such as pentane and hexane. The third reaction zone contains 10 hot reaction gases.
A liquid or gaseous cooling medium such as water is sprayed from the reaction stopping fluid introducing nozzle 7 to cool the liquid to a temperature of 00 to 800 ° C. or lower. 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 the figure, reference numeral 8 denotes a control valve.

In order to obtain the carbon black of the present invention, when producing the carbon black using the above furnace, various conditions in the carbon black producing region in the furnace, including the conditions for the position where the raw material hydrocarbon is introduced, are appropriately adjusted. The adjustment is suitably performed. Specifically, the oxygen concentration in the combustion gas at the site where the raw material hydrocarbon is introduced is set to about 5 to 10 vol% because it was considered that the furnace gas was generated by partial combustion of the raw material hydrocarbon in the conventional furnace method. Was partially burned, but in order to obtain the carbon black of the present invention, usually 3 vol% or less,
Preferably, it should be 0.05 to 1 vol%. It is extremely surprising that by reducing the oxygen concentration at the feed hydrocarbon introduction position as much as possible, such a small particle diameter, a small and uniform aggregate diameter, and a large-diameter aggregate were suppressed. Carbon black can be obtained with good yield. In addition, the measurement of the oxygen concentration in the raw material hydrocarbon introduction site is performed by sampling the gas in the raw material hydrocarbon introduction site and measuring, for example, nitrogen, oxygen, carbon dioxide, carbon monoxide, hydrogen, methane, and acetylene with a gas chromatography measurement device. The water generated by combustion is not included in the calculation.

The temperature at the site where the raw material hydrocarbon is introduced is usually 1800 ° C. or higher, preferably 1900 ° C. or higher, particularly preferably 2000 to 2400 ° C. In such a temperature range, the small particle diameter, small aggregate diameter and sharp It is advantageous to obtain carbon black having an aggregate distribution. 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, it is considered that 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.

In order to set the temperature of the portion where the raw material hydrocarbon is introduced within the above range, oxygen can be added to air, for example, when a high-temperature combustion gas stream is formed in the first reaction zone. Of course, the method of increasing the combustion gas temperature is not limited to the addition of oxygen, but may be a method of preheating air or the like. 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 length of the choke portion is 500 mm or more, preferably 800 to 3000 mm. The present inventors have found that particularly in this range, the diameter of the aggregate of the obtained carbon black can be made particularly small, and the form of the aggregate can be made desired.
In addition, the entrance of the chalk part which is the chalk part start site,
It includes the narrowest part of the flow path, and refers to a part where the angle with respect to the axial direction in which the flow path contracts changes from a value exceeding 5 ° to 5 ° or less. On the other hand, the exit of the choke portion, which is the terminal end of the choke portion, refers to a portion where the angle with respect to the axial direction in which the flow path is reduced has a value exceeding 5 °. The diameter of the chalk is preferably 170 mm or less, particularly preferably 30 to 170 mm, most preferably 50 to 150 mm. The faster the gas flow rate in the chalk, the better. After introduction of the raw material hydrocarbons, they are 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, usually 250 m / s or more, and preferably 300 to 500 m / s.

In order to uniformly disperse the starting hydrocarbons in the furnace, the starting hydrocarbons are preferably 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 portion and within 1 ms based on the average cross-sectional flow velocity of the combustion gas from the choke inlet. More preferably, it is within the range of 0.6 ms. By introducing at this site, carbon black having a particularly small particle diameter and a uniform aggregate diameter can be obtained.

By preparing the coating composition, resin composition, and rubber composition containing the carbon black of the present invention described above, it is possible to exhibit suitable characteristics for 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.

When preparing the resin composition containing carbon black of the present invention, the applicable resin is not particularly limited, and examples thereof include various thermoplastic resins or thermosetting resins, mixtures of these resins, and fillers. May be added. Usually, 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 rubber kneading machine, 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, 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 1 to 60% by weight.

In preparing the coating composition containing 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 resins or maleic resins, alkyd resin paints, aminoalkyd 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 employing a known technique.
10% by weight is preferred.

In preparing the rubber composition containing the carbon black of the present invention, the carbon black of the present invention may be blended with at least one of natural rubber and synthetic rubber. In general, the amount of carbon black is preferably 30 to 150 parts by weight based on 100 parts by weight of rubber. Thereby, it is possible to obtain a rubber having a small loss coefficient and a small calorific value. The rubber component used at this time is not particularly limited, either.
For example, as a synthetic rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, nitrile butadiene rubber, isobutylene isoprene rubber, ethylene propylene rubber, silicone rubber, fluorine rubber,
Chlorosulfonated polyethylene, chlorinated polyethylene,
Polysulfide rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber, propylene oxide rubber, ethylene / vinyl acetate copolymer, liquid rubber, polyalkylene sulfide, nitroso rubber, etc., and of course, natural rubber or various mixtures thereof. Can be. Further, various additives can be blended as required.
The carbon black of the present invention is added to the above rubber component and kneaded to obtain a rubber composition. The kneading machine may be one usually used as a rubber kneading machine, and examples thereof include a roll mixer, a Banbury type mixer, a continuous screw or continuous rotor type single-screw kneading extruder, and a twin-screw kneading extruder.

[0027]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Examples 1 and 2 A first reaction zone provided with an air introduction duct and a combustion burner as shown in FIG. 2, an inner diameter of 60 mm, a length of 1000 m connected to the first reaction zone and having a plurality of raw material nozzles penetrating therethrough from the periphery.
A carbon black production furnace having a structure in which a second reaction zone having a choke portion of m and a third reaction zone having an inner diameter of 100 mm and a length of 6000 mm equipped with a quench device were sequentially connected was installed.

The position of the raw material nozzle is 100 mm from the entrance of the choke section. Using the above furnace, the combustion gas temperature at the feed hydrocarbon introduction position is in the range of 1900 to 2100 ° C., the combustion gas oxygen concentration is 3 vol% or less,
By adjusting the raw material supply amount, carbon black having the physical properties shown in Table 1 was produced. Creosote oil was used as fuel and raw hydrocarbon. The high temperature of the combustion gas was realized by adding oxygen to the air introduced from the air introduction duct in the first reaction zone. The gas flow rate at the feed hydrocarbon introduction position is 400 to 500 m /
s. The following test methods were used to determine the physical properties of carbon black in Table 1.

(Average particle size) By electron microscopy. Electron microscopy is a method described below. Carbon black is injected into chloroform and 200 KHz ultrasonic wave is applied for 20 minutes.
After irradiating for minutes, the dispersion sample is fixed to a 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 is performed about 1500 times, and the values are obtained by arithmetic averaging.

(N ₂ SA specific surface area) ASTM D303
Determined according to 7-88. (CDBP) Determined according to ASTM D-2414. (D _mod , D _1/2 ) The maximum frequency Stokes equivalent diameter (D _mod ) and the Stokes equivalent diameter _half width (D _1/2 ) were determined as follows. Using a 20% ethanol solution as a spin solution, the Stokes equivalent diameter was measured by a centrifugal sedimentation type flow rate distribution measuring device (DCF3 type manufactured by JL Automation), and the relative frequency of the Stokes equivalent diameter versus the given sample was given. (FIG. 3). 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 the two points D and E of the carbon black particles is the Stokes equivalent diameter _half width D1 _{/ 2} value.

(D ₇₅ ) The volume 75% diameter (D ₇₅ ) was determined as follows. In the above method for determining the maximum frequency Stokes diameter, a histogram of the Stokes equivalent diameter versus the relative frequency of occurrence of the sample The volume is obtained from each Stokes diameter and frequency from FIG. 3, and the Stokes diameter versus the volume of the sample obtained up to that diameter. A graph representing the sum is created (FIG. 4).
Therefore, point (A) in FIG. 4 represents the sum of the volumes of all the samples. Here, a point (B) having a value of 75% of the total volume is determined, and a point (C) at which the curve intersects the curve on the X axis from the point (B)
Draw a line until. Draw a line from point (C) to the Y axis at equilibrium, and
The value of the point (D) crossing the axis is the volume 75% diameter (D ₇₅ ).

(PVC Blackness) The PVC blackness was determined by adding 1 part by weight of the carbon black of the present invention to 100 parts by weight of a PVC resin, dispersing and sheeting with two rolls, and carbon black “# 40” manufactured by Mitsubishi Chemical Corporation. , "# 45", the blackness of each sample was set at 1 point and 10 points, respectively, and a reference value was determined.

(Dispersion index) The dispersion index was evaluated by the following method. The state of dispersion in the LDPE resin was observed, and the number of undispersed aggregates was counted. The larger the number, that is, the larger the dispersion index, the worse the dispersibility was evaluated. 250c
c Using a Banbury mixer, 40% by weight of the sample carbon black is blended with the LDPE resin and kneaded at 115 ° C. for 4 minutes. Mixing conditions LDPE resin 101.89 g Calcium stearate 1.39 g Irganox 1010 0.87 g Sample carbon black 69.43 g Next, the mixture is diluted with a two-roll mill at 120 ° C. so that the carbon black concentration becomes 1% by weight. Diluting compound preparation conditions LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 40% blended resin 1.5 g Slit width 0.3 mm, cut into sheets, cut into chips, 65 ± 3 μm on 240 ° C hot plate
Into a film. The diameter distribution of undispersed aggregates having a diameter of 0.2 mm or more in a 3.6 mm × 4.7 mm field of view is measured with an optical microscope having a magnification of 20 ×, and the total area is calculated. This area is calculated by dividing the total area by the reference area based on the area of the undispersed aggregate having a diameter of 0.35 mm as the number of reference particles. This is observed in 16 or more visual fields, and the average value is used as the dispersion index.

Comparative Examples 1 to 4 Using the carbon black production furnace used in Example 1, the combustion gas temperature at the feed hydrocarbon introduction position, the reaction stop position, the amount of potassium added, and the gas flow rate in the chalk were adjusted as shown in Table 1. Carbon blacks having the physical properties of Comparative Examples 1 and 2 shown were obtained. Further, Comparative Examples 3 and 4 showed physical properties of commercially available carbon black.

[0035]

[Table 1]

Comparing each of the examples with each of the comparative examples, the examples have a dispersion index of 1000 or less in the range where the blackness is 25 or more, and the dispersibility is equal at the same blackness as the comparative example. Are better.

[0037]

When the carbon black of the present invention is used as a black pigment in a resin colorant, a paint or the like, it can satisfy the blackness and dispersibility which have been conventionally difficult and difficult. In addition, the resin composition is excellent in the prevention of deterioration when used as a resin composition, the abrasion resistance when used as a rubber composition, and the effect of preventing aggregation when used as a coating composition, and has high safety. Therefore, it is very useful in preparing resin colorants, paints, and rubber compositions.

[Brief description of the drawings]

FIG. 1 is a diagram showing the maximum projection length and width of an aggregate.

FIG. 2 is a diagram showing a method of obtaining a perimeter fractal dimension.

FIG. 3 is a schematic longitudinal sectional view of an essential part showing an example of a production furnace that can be used for producing the carbon black of the present invention.

FIG. 4 is a diagram showing a method of obtaining the maximum frequency Stokes equivalent diameter (D _mod ) and the Stokes equivalent diameter _half width (D _1/2 ).

FIG. 5 is a diagram showing a method for _{obtaining a} volume 75% diameter (D ₇₅ ).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 201/00 C09D 201/00

Claims (7)

[Claims] An average particle diameter of 30 nm or less and a D _mod of 1
00 nm or less, the perimeter fractal dimension of the aggregate is 1.35 or more, and / or the anisotropic ratio of the aggregate is 0.620.
A carbon black that is: 2. The carbon black according to claim 1, wherein the ratio of D _1/2 / D _mod is 0.6 or less. 3. The carbon black according to claim 1, wherein D ₇₅ / D _mod is 1.6 or less. 4. The carbon black according to claim 1, wherein N ₂ SA is 80 m ² / g or more. 5. A coating composition comprising the carbon black according to claim 1. 6. A resin composition comprising the carbon black according to claim 1. 7. A rubber composition containing the carbon black according to any one of claims 1 to 4.