JPH11335580A - Carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy blackness and dispersibility which are conventionally an antinomy by specifying an average particle diameter, a ratio of N2 SA/SEM specific surface area, a pH value and a cDBP. SOLUTION: A carbon black is prepared such that the average particle diameter is 14 nm or less, preferably 8-12 nm; the ratio of N2 SA/SEM specific surface area is 1.3 or more, preferably 2.8 nm or less; the pH value is 5 or more, preferably 6 or more; and the cDBP is 50 cc/100 g or more, preferably 60 cc/100 g or more. Preferably Dmod is 80 nm or less and/or the ratio of D1/2 /Dmod is 0.6 or less and more preferably 0.55 or less. Moreover, the ratio of D75 /Dmod is preferably 1.6 or less. This carbon black is extremely excellent in dispersibility in a variety of vehicles and highly black and gives suitable characteristics (non-aggregation, prevention of degradation, abrasion resistance) to paint compositions, resin compositions, rubber compositions and ink compositions which contain this carbon black.

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 a filling material, a reinforcing material, a conductive material and a coloring pigment.

[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. Generally, carbon black is produced in a first reaction zone of a cylindrical carbon black production furnace in a furnace axial direction. Alternatively, the oxygen-containing gas and the fuel are introduced in a tangential direction, and the high-temperature combustion gas stream obtained by the combustion is successively moved to a second reaction zone installed in the furnace axis direction, and is introduced into the gas stream. A furnace type production method in which a raw material hydrocarbon is introduced to generate carbon black and the reaction gas is rapidly cooled in a third reaction zone to stop the reaction is widely known.

[0003] Carbon black used as a colorant in resin colorants, printing inks and paints is required to have excellent blackness, dispersibility, gloss and coloring power, and is mainly used as a reinforcing agent for automobile tires. The carbon black to be used is required to have excellent wear resistance. Carbon black particles exist in a state where the particles are fused together like skewered dumplings.Each spherical particle only characterizes the dumplings and the peaks and valleys of the dumplings, but this is a single particle The particle diameter considered to be considered is closely related to the performance in various applications, for example, the reinforcing property and blackness. (Carbon Black Handbook 3rd Edition, I. General Overview, p. 7).

[0004] The particle diameter can be determined by taking a photograph of several tens of thousands times with an electron microscope having a resolution of at least 1.5 to 2 nm and directly measuring it. When referring to the particle size of carbon black, it usually refers to the particle size of carbon black measured in this way, and this particle size is in the range of 10 to 300 nm depending on the grade and belongs to the so-called aerosol or colloid region. I have. It is known that the blackness / coloring power when carbon black is used as a black pigment greatly depends on the particle size 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. It is also known that carbon black having such a small particle size exhibits a high degree of wear resistance when used as a tire reinforcing agent.

[0005] On the other hand, the particle size distribution also has a significant effect on rubber properties, particularly on tire tread rubber compositions that require high abrasion resistance, and it is said that a narrower particle size distribution is more preferable. Generally, the smaller the average particle size, the narrower the distribution. Further, as an important factor affecting the physical properties of the product when carbon black is used, there are aggregates as well as the particle diameter. The size of the agglomerates is determined by the tensile stress and extrusion characteristics when compounded with rubber, the dispersibility and blackness when compounded with ink and paint vehicles and resins,
It has a great effect on viscosity. 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,
It is important for the application properties of carbon black.

Regarding the effect of aggregates, the size and distribution of the aggregates are quantified by regarding the aggregates as simple particles. By treating the aggregates as particles, various particle diameter measurement techniques can be applied, and the size of the aggregate measured in this way is expressed as the aggregate diameter. Agglomerates have a significant effect on the properties of carbon black, and it has become clear that many of the properties of carbon black, previously thought to be due to particle size, can be better explained by the aggregate size. Was. For example, it is considered that the diameter of the aggregate plays a large role in optical properties such as coloring power and dynamic viscoelastic properties and reinforcing properties of the compounded rubber composition. It is known that the smaller the agglomerate diameter, the higher the degree of blackness when viewed in resin coloring applications. In addition, as an index of the aggregate, besides the aggregate diameter which is an index when this is regarded as a particle, for example, DBP, cDB
An index such as P is known. The effect of cDBP on the degree of blackness and dispersibility is also known. It is said that the lower the cDBP, the higher the degree of blackness but the lower the degree of dispersion. As described above, two factors of the particle size and the aggregate are important for the application characteristics of carbon black.

When carbon black is used as a black pigment, ultrafine carbon black having a particle size of 15 nm or less has a high degree of blackness, and is used in high-grade paints and high-grade resin colorants. This class of carbon black is manufactured by HCC (High Colo
r Channel) and furnace-processed HCF (Hig
h Color Furnace).

[0008] Among the small particle diameters, ultrafine carbon black having a particle diameter of less than 14 nm has a very high degree of blackness and is used for the highest grade paints and the highest grade resin coloring. The majority of the commercial products are manufactured by. In the channel method,
This is because carbon black having an ultrafine particle diameter of 13 to 14 nm and a sharp particle diameter distribution can be produced, and it exhibits a very high blackness. Particularly in the field of high-grade paints and high-grade resin colorants, carbon black exhibiting the highest blackness tends to dominate the market.

In the furnace method, in order to obtain carbon black having a small particle diameter, first, a raw material hydrocarbon is sprayed into a high-speed gas flow in a choke section provided in a second reaction zone, and the kinetic and thermal energy of the gas are increased. It is well-known that it is effective to utilize a liquid feedstock to atomize it. It is also known that carbon black having a small particle diameter can be obtained by reducing the amount of the base oil to be injected with respect to the amount of the combustion gas. However, if the injection ratio of the base oil is reduced, the productivity of carbon black decreases. It is also well known that increasing the gas temperature in the feedstock injection region is effective for efficiently producing carbon black having a small particle diameter as a method of not reducing the productivity. In this regard, in the production of furnace black, it has been generally performed to raise the temperature of the carbon black producing region by leaving a certain amount of residual oxygen in the gas at the feedstock injection portion and partially burning the feedstock itself. . However, in this method, a part of the injected base oil is not used as carbon black but is used in a combustion reaction, so that the yield is deteriorated.

In the conventional furnace method, it is difficult to stably produce particles having a particle diameter of about 11 to 14 nm. It was not possible to exhibit the same degree of blackness as the channel Bunrak. In addition, in order to obtain particles having a small particle size, it is necessary to extremely reduce the amount of raw material hydrocarbons charged into the furnace with respect to the amount of combustion gas generated in the furnace, resulting in an extremely high product yield. The result is a decrease. Also, in order to obtain high blackness by the conventional furnace method, it is necessary to reduce the particle size and DBP. Generally, as a method for lowering DBP, an alkali metal salt or a solution thereof is added to a raw material oil or introduced into a combustion zone or a reaction zone. In the case where it is blended, there is a disadvantage that deterioration of dispersibility and fluidity is caused.

Conventionally, carbon black produced by the furnace method corresponding to channel black is:
There are some reports. For example, Japanese Patent Publication No. 54-7632 discloses a method in which a raw material hydrocarbon is vaporized and supplied into a furnace, and an EM average particle diameter (corresponding to an average particle diameter described later) 9
carbon black having a BET specific surface area / EM specific surface area ratio of 1.25,
M average particle diameter 14 nm, EM particle diameter standard deviation 5.5 n
m, it is stated that a carbon black having a BET specific surface area / EM specific surface area ratio of 1.25 was obtained.

However, judging from the ratio of BET specific surface area / EM specific surface area of 1.3 or less, it is presumed that the ratio of polycyclic aromatic hydrocarbons is large, and as described later, there is a problem in safety. It is thought that there is.

[0013] On the other hand, the channel method can produce carbon black of ultra-fine particles and high blackness. However, since it is produced in an oxygen atmosphere, the production process itself has poor product yield and low productivity. I have. For example, "FW200" (trade name, manufactured by Degussa Co., Ltd.) is marketed as a channel black having a small particle diameter manufactured by the channel method, and the particle diameter is 13 nm (catalog value). However, since the channel black obtained by such a channel method is produced in an oxygen atmosphere, the carbon black itself shows acidity. This has the following important disadvantages: That is, (1) when blended with a resin, the obtained resin composition tends to deteriorate. (2) When compounded with rubber, the obtained rubber composition has poor abrasion resistance. (3) When an aqueous coating composition is prepared, carbon black tends to aggregate in the coating composition. It has the drawback inherently.

On the other hand, unreacted polycyclic aromatic hydrocarbons remaining in carbon black have been pointed out in recent years also as a risk of carcinogenicity. It has come to be considered that there is also a problem with safety. Therefore, it has the same degree of blackness as channel black by the furnace method with good production efficiency, and also has good dispersibility when blended in paints and resins, and has a low ratio of unreacted polycyclic aromatic hydrocarbons in the product. It is required to produce a carbon black.

[0015]

As described above,
Regarding the relationship between the properties of carbon black and the properties of a carbon black-containing composition such as a resin composition, it is an important issue how to satisfy blackness, dispersibility, and safety, which are generally reciprocal relationships. I have. Further, it is also required that the rubber composition is excellent in abrasion resistance when compounded with a rubber component, and that deterioration in the resin composition is suppressed. Moreover, once dispersed carbon black must not re-agglomerate. An object of the present invention is to provide a carbon black that can maintain high blackness, good dispersibility, prevent agglomeration, and have high safety when various carbon black-containing compositions are prepared. It is.

[0016]

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.
In particular, various studies were conducted on a method for producing a carbon black having a blackness equal to or higher than that of the channel black and having good dispersibility and safety by the furnace method. As a result, the present inventors have found that the dispersibility of the carbon black is affected by various physical properties of the carbon black in addition to the particle diameter and the aggregate, and a representative example thereof is a pH value. That is, when the pH value is low, there are drawbacks such that the resin is largely decomposed when mixed with the resin, and aggregation tends to occur when used as an aqueous paint. It was found to contribute to.

Further, when the ratio of the specific surface area of N ₂ SA / SEM does not reach a specific value, it has been found that the proportion of unreacted polycyclic aromatic hydrocarbons remaining in carbon black is so large as to be not negligible. . In recent years, polycyclic aromatic hydrocarbons have also been pointed out as a danger of carcinogenicity.If the content of carbon black as a product in a product is large, it is considered that there is also a problem with safety. It is required to obtain a carbon black which exhibits good characteristics while suppressing it. Further, the ratio of the N ₂ SA / SEM specific surface area indicates the degree of the pore area on the surface of the carbon black particles. If this value does not reach a specific value, for example, the monomer is polymerized on the carbon black surface. As a result, it has been found that the degree of the surface treatment may be reduced, for example, when the surface treatment of the carbon black such as the grafting treatment for coating the polymer is performed, the grafting ratio is lowered. Also,
When used as conductive black, conductivity is reduced.
Further, when platinum and other metals are supported and used as a catalyst carrier, the catalyst has a disadvantage that the particle size of the catalyst becomes large and the activity is hardly obtained.

That is, in order to obtain carbon black having high blackness, high dispersibility and high safety, it is needless to say that basic characteristics of carbon black such as particle diameter and size of aggregates are important. However, besides this, pH and N ₂ SA /
The present inventors have found that properties such as the ratio of the SEM specific surface area are also very important, and it is important to control these properties to a desired range. In particular, by setting the balance between the pH and the specific surface area of N ₂ SA / SEM within a specific range, the abrasion resistance of the rubber composition is kept high, the deterioration of the resin composition is prevented, and the water-based paint is used. They have found that aggregation can be prevented. Therefore, it has been desired to efficiently produce carbon black having these various controlled properties.

In the above-mentioned Japanese Patent Publication No. 54-7632, carbon black having a ratio of BET specific surface area / EM specific surface area of 1.3 or less is described.
Regarding the ratio of ET specific surface area / EM specific surface area, no mention is made of the drawbacks when the value is too small, and also the size and distribution of pH and agglomerates, which are important properties that determine the degree of blackness together with the particle size, Neither cDBP nor its influence on dispersibility or blackness is described or suggested at all.

The present inventors have found that the average particle size, N ₂ SA
A new carbon black having a specific range of the ratio of / SEM specific surface area, pH value and cDBP value was successfully produced, and it was found that this carbon black exhibited extremely excellent properties.

That is, according to the present invention, the average particle diameter is 14n.
m or less, and the ratio of the N ₂ SA / SEM specific surface area is 1.3.
Greater, with a pH value of 5 or more and cDBP of 50 cc /
100 g or more of carbon black, a coating composition, a resin composition, a rubber composition, and an ink composition containing such carbon black.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The carbon black of the present invention has an average particle diameter of 14 nm or less. Particularly preferably, it is 8 to 12 nm. Particle size 14
If it exceeds nm, the degree of blackness when formed into a coating is not sufficient.
Here, the average particle size refers to the average particle size determined by electron microscopy. The carbon black of the present invention is
Further, the ratio of the N ₂ SA / SEM specific surface area is larger than 1.3. There is a correlation between this ratio and the proportion of unreacted polycyclic aromatic hydrocarbons remaining in the carbon black,
When the ratio is 1.3 or less, the amount of polycyclic aromatic hydrocarbons cannot be ignored and is not desirable in terms of safety. In the present invention, the ratio of the N ₂ SA / SEM specific surface area is set to be larger than 1.3, preferably 1.5 or more, and more preferably 1.8 or more. On the other hand, if the ratio is too large, the viscosity at the time of preparing the ink composition may increase or adversely affect the dispersibility. Therefore, usually, it is desirable to be 2.8 or less, especially 2.5 or less.

The ratio of the N ₂ SA / SEM specific surface area is N ₂ S
A and SEM specific surface areas are determined, respectively, and the ratio is calculated. ASTM D3 for N ₂ SA measurement
037-88. The measurement of the SEM specific surface area is calculated by the following equation. SEM = 6000 / (ρ · dA) ρ: Specific gravity of carbon black (1.86 g / cm ³ ) dA: Body area particle diameter (nm)

Further, the carbon black of the present invention has a pH of 5 or more. When the pH is less than 5, the resin composition is easily deteriorated when such a carbon black is used, and the abrasion resistance is poor when a rubber composition is used using such a carbon black. When an aqueous paint is prepared using such carbon black, there is a problem that carbon black is likely to aggregate. Particularly preferably, it is 6 or more. The measuring method of pH is JISK6
221-1982. As described above, the pH of a channel black conventionally marketed as a carbon black having an excellent blackness and having a small particle size is as low as less than 5, usually less than 3, due to its production method.

In the present invention, the cDBP is 50
cc / 100 g or more. cDBP
Is also called crushed DBP absorption number, and is ASTM
It is measured according to D-3493-88,
When cDBP is less than 50 cc / 100 g, dispersibility is poor. The value of cDBP is particularly preferably 60 cc / 100.
g or more. The carbon black of the present invention satisfies both the blackness and the dispersibility by setting the particle diameter, the ratio of the N ₂ SA / SEM specific surface area, the pH and the cDBP in the specific ranges described above, and further improves the safety. Can also be excellent.

In the present invention, the diameter of the aggregate is particularly limited.
No, but preferably D_modIs less than 80nm, more preferable
Or less than 40 nm. Aggregate diameter is determined as described above.
The role played in diffuseness and blackness is gradually becoming clearer
However, in the present invention, a specific particle size, a specific N_TwoSA
/ SEM specific surface area ratio, specific pH and specific cDBP
In carbon black adjusted to_modIs 80n
m, more preferably 40 nm or less.
Demonstrate the nature. Even more preferably, the maximum frequency storage
Half width D of equivalent diameter_1/2And maximum frequency Stokes equivalent diameter
D_modRatio, D_1/2/ D_modLess than or equal to 0.6, preferably
By adjusting to 0.55 or less, extremely excellent blackness
And dispersibility is improved. In addition,
75% volume D within the range of light₇₅And D_modThe ratio of
D₇₅/ D _modIs preferably 1.6 or less, particularly preferably
1.3 or less. This has a negative effect on dispersion
Extremely low content of large aggregate diameter exceeding 75% volume
It has been suppressed.

The carbon black of the present invention described above has such excellent characteristics in both blackness and dispersibility. To obtain these carbon blacks of the present invention efficiently, the following method is required. Can be taken. In FIG.
FIG. 1 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, in its longitudinal direction, a first reaction zone 1 for forming a high-temperature combustion gas stream and a second choke section for mixing raw hydrocarbon with the obtained high-temperature combustion gas stream to produce carbon black. 2 reaction zone 2 and a third reaction zone 3 downstream of and following the second reaction zone to stop the reaction
It is divided into and. 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 starting hydrocarbon is spray-injected from the starting hydrocarbon introducing nozzle 6 provided in parallel or in the horizontal direction with the high-temperature gas stream obtained in the first reaction zone, and the starting 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.

The third reaction zone is provided with a high-temperature reaction gas of 1,000 to 1,000.
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 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-mentioned 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 hydrocarbon is introduced is 3 vol.
It should be 1% or less, preferably 0.05 to 1% by volume. Surprisingly, it has been found that the carbon black having a small particle diameter of the present invention can be obtained with a high yield by minimizing the oxygen concentration at the position where the raw hydrocarbon is introduced.

Conventionally, furnace black obtained by the furnace method has been considered to be produced by partial combustion of raw material hydrocarbons. Therefore, the concentration of residual oxygen in the combustion gas at the raw material hydrocarbon introduction site is set to about 5 to 10 vol%. The feedstock was partially burned. The inventors have surprisingly found that by suppressing the oxygen concentration to a very small amount, the aggregate distribution is sharp, there is no aggregate having a large particle diameter, and further, the carbon black having a small aggregate diameter and a small particle diameter is increased. They found what they could get at a yield. The measurement of the oxygen concentration at the feed hydrocarbon introduction site
The gas can be obtained by sampling the gas at the starting hydrocarbon introduction site and measuring, for example, nitrogen, oxygen, carbon dioxide, carbon monoxide, hydrogen, methane, and acetylene using a gas chromatography measurement device. Water generated by combustion is not included in the calculation.

The temperature at the site where the raw material 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, small particle size carbon black can be easily obtained.

In order to set the temperature of the site 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 stream 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.

Here, the inlet of the choke portion, which is the starting portion of the choke portion, includes the narrowest portion of the flow path, and the angle with respect to the axial direction in which the flow path is reduced from 5 ° to 5 °.
The following are the parts that change. On the other hand, the outlet of the choke portion, which is the terminal 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 3
It is 0 to 170 mm, 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 the feed hydrocarbon is introduced, it 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 300 m / s or more.
５００500 m / 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 starting hydrocarbons in the furnace, it is preferable to introduce the starting hydrocarbons into the furnace from two or more nozzles. The feed position of the raw hydrocarbon is
It is preferable to set the range within 1 ms within the choke portion and on the basis of the cross-sectional average 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 the combination of these conditions, the distribution of aggregates is extremely sharp at a small aggregate diameter, the generation of aggregates having a large particle diameter is suppressed, and the pH and N ₂
The present inventors have found that the carbon black of the present invention in which the ratio of the SA / EM specific surface area is controlled to a constant value can be obtained with good yield by the furnace method. That is, the carbon black of the present invention described above, which has been conventionally difficult to produce, can be obtained by the above-described production method.

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. Further, in the carbon black of the present invention, pH, N ₂
By setting the ratio of SA / EM specific surface area and cDBP to specific ranges, a rubber composition having excellent abrasion resistance can be obtained, and a resin composition which is hardly deteriorated can be obtained.
In addition, aggregation in the aqueous coating composition can be prevented. The carbon black of the present invention, which can obtain an excellent carbon black-containing composition by being blended with various vehicles as described above, is a novel carbon black that has not existed so far. It can be easily 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 for containing any one of the carbon blacks of the present invention. 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 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. However, as described above, the carbon black of the present invention is excellent in the effect of preventing agglomeration particularly when an aqueous coating composition is prepared, and thus used in the preparation of aqueous coating compositions such as emulsion coatings and water-soluble resin coatings. In this case, it is preferable because particularly remarkable high characteristics can be exhibited.

The content of carbon black may also be determined by employing a known technique, and is generally preferably 0.1 to 10% by weight. Further, in preparing the rubber composition containing the carbon black of the present invention, the carbon black of the present invention may be blended with one or more 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, and examples thereof include styrene butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, nitrile butadiene rubber, isobutylene isoprene rubber, ethylene propylene rubber, silicone rubber, fluoro rubber, and chloro rubber. Sulfonated polyethylene, chlorinated polyethylene, polysulfide rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber, propylene oxide rubber, ethylene-vinyl acetate copolymer, liquid rubber, polyalkylene sulfide, nitroso rubber, and of course, natural rubber, Alternatively, these various mixtures can also be used. 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. 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. Various known methods may be used for the dispersion method, and various additives may be added.

[0043]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. (Examples 1 to 4) A first reaction zone provided with an air introduction duct and a combustion burner as shown in FIG. 1, and an inner diameter of 60 m connected to the first reaction zone and having a plurality of raw material nozzles penetrating therethrough from the periphery.
m, second reaction zone with a 1000 mm long choke, inner diameter 100 mm length 6000 with quench device
A carbon black production furnace having a structure in which a third reaction zone of mm was 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, carbon black having the physical properties shown in Table 1 was produced by adjusting the combustion gas temperature, the combustion gas oxygen concentration, and the raw material supply amount at the raw material hydrocarbon introduction position. Creosote oil was used as fuel and raw hydrocarbon. Oxygen was added to the air introduced from the air introduction duct in the first reaction zone, and a high-temperature atmosphere of 1900 ° C. or higher at the feed hydrocarbon introduction position was maintained. 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) The N ₂ SA specific surface area was determined according to ASTM D3037-88. (SEM specific surface area) The SEM specific surface area was calculated from the following equation. SEM = 6000 / (ρ · dA) ρ: Specific gravity of carbon black (1.86 g / cm ³ ) dA: Body area particle diameter (nm)

(CDBP) Crushed DBP absorption number (cDB
P) was determined according to ASTM D-3493-88. (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 occurrence frequency in the given sample relative to the Stokes equivalent diameter (FIG. 2). 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.

(D ₇₅ ) The volume 75% diameter (D ₇₅ ) was determined as follows. In the above method of 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 determined from each Stokes diameter and frequency from FIG. 2, and the Stokes diameter versus the volume of the sample obtained up to that diameter Make a graph that represents the sum. (Fig. 3)
Therefore, the point (A) in FIG. 3 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 line is drawn from the point (B) to the X axis until the curve intersects the equilibrium. A line is equilibrium drawn from the point (C) to the Y axis, and the value at the point (D) crossing the X axis is the volume 75% diameter (D ₇₅ ).

(PVC Blackness) The PVC blackness was determined by adding the carbon black of the present invention to a PVC resin, dispersing and sheeting with two rolls, and using a carbon black “# 40” or “# 45” manufactured by Mitsubishi Chemical Corporation. The blackness was defined as a reference value of 1 point and 10 points, respectively, and the blackness of the sample was evaluated by visual perception.

(T%) Toluene coloring power (T%) is AST
Determined according to MD-1618-83.

(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. Formulation 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. Conditions for preparing dilution compound LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 40% blended resin 1.5 g Slit width 0.3 mm, cut this sheet into chips, and 65 ± 3 μm on a 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.

(Heat aging time) The heat aging time was evaluated by the following method. Dispersant (magnesium stearate)
And a 40% mixture of carbon black, and pulverize and mix in a household mixer for 10 minutes to prepare a dry color. Next, a dry color was blended with 1.25% (carbon black 0.5%) in a polypropylene compound and kneaded with a bumper mixer at 140 ° C. for 20 minutes.
Sheets are formed at 170 ° C. with this roll mill. Mold temperature 22
It is press-molded into a 2 mm thick flat plate at 0 ° C. and a molding pressure of 100 kgf / cm ² . Five test pieces each prepared in this manner were placed in a gear oven at 150 ° C. for 28 days.
The heat aging test is performed for 5 hours. The time when the surface began to whiten visually was defined as the heat aging time.

(Comparative Examples 1 to 5) Using the carbon black production furnace used in the examples, 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 to obtain the values shown in Table 1. The carbon blacks having the physical properties of Comparative Examples 1 and 2 shown in Table 1 were obtained. Comparative Example 3
-5 showed the physical properties of commercially available carbon black. When each example is compared with Comparative Example 1, the PVC blackness of the Example is much higher than that of Comparative Example 1. This is considered to be because in Comparative Example 1, the particle diameter was out of the range specified in the present invention. Further, when comparing each example with comparative example 2, the value of T% is high in the example. This indicates that the ratio of unreacted polycyclic aromatic hydrocarbons in the carbon black is low, which means that the safety of the carbon black is high. The value of the ratio of Comparative Example 2, N ₂ SA / SEM is believed to be due to out of the range defined in the present invention, N ₂
This shows that there is a correlation between the ratio of SA / SEM and the ratio of unreacted polycyclic aromatic hydrocarbon. When each example is compared with Comparative Example 3, in Comparative Example 3, the heat aging time is significantly shorter than in the Examples. This is considered to be because the pH was out of the range specified in the present invention. When each example is compared with Comparative Examples 4 and 5, in Comparative Examples 4 and 5, the dispersion index is large and the dispersion is poor compared to the examples. This is considered to be because cDBP is out of the range defined in the present invention.

[0055]

[Table 1]

[0056]

The carbon black of the present invention, when used as a black pigment in a resin colorant, printing ink or paint, satisfies the blackness and dispersibility which have been conventionally difficult and difficult. Productivity can be improved. In addition, it 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. Therefore, it is very useful in preparing resin colorants, paints, and rubber compositions.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an essential part showing an example of a production furnace that can be used for producing carbon black of the present invention.

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

FIG. 3 is a diagram showing a method for _{obtaining a} volume 75% diameter (D ₇₅ ).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st reaction zone 2 2nd reaction zone 3 3rd reaction zone 4 refractory furnace 5 nozzle for fuel and oxidizing gas introduction 6 feed oil introduction nozzle 7 reaction stop fluid introduction nozzle 8 control valve

Claims (8)

[Claims] An average particle size of 14 nm or less, and N ₂
Carbon black having a SA / SEM specific surface area ratio of greater than 1.3, a pH value of 5 or more, and a cDBP of 50 cc / 100 g or more. 2. The method according to claim 1, wherein D _mod is not more than 80 nm.
The described carbon black. 3. The carbon black according to claim 1, wherein the ratio of D _1/2 / D _mod is 0.6 or less. 4. The carbon black according to claim 1, wherein the ratio of D _1/2 / D _mod is 0.55 or less. 5. A coating composition comprising the carbon black according to claim 1. Description: 6. A resin composition comprising the carbon black according to claim 1. 7. A rubber composition comprising the carbon black according to claim 1. Description: 8. An ink composition comprising the carbon black according to any one of claims 1 to 4.