JP2008285632A - High jetness carbon black dispersion, process for producing the same, and coating material composition using the high jetness carbon black dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for easily producing a carbon black dispersion which has carbon black having a primary particle size of 15 nm or less finely dispersed in an aqueous medium with excellent dispersion stability, appropriate fluidity and high jetness and is produced in applications where finely-divided particles and high jetness are required such as an aqueous coating material, an aqueous ink, an automotive coating material or the like using an aqueous pigment dispersion, to provide the thus-produced carbon black dispersion and to provide a composition using the carbon black dispersion. <P>SOLUTION: A high jetness carbon black dispersion acquires high jetness by allowing carbon black having a DBP oil absorption of not more then 150 ml/100 g, an average primary particle size of 15 nm or less, a specific surface area of not more than 500 m<SP>2</SP>/g and a pH within the acidic or neutral pH range to be dispersed in the form of a fine particle into an aqueous medium with the aid of a pigment dispersant. A process for producing a carbon black dispersion which acquires high jetness as described above and the high jetness carbon black dispersion produced by the production process are provided. An automotive coating material composition, an aqueous coating material and an aqueous ink composition each comprising the high jetness carbon black dispersion are provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high jet black carbon black dispersion and a method for producing the same, and a coating composition and an ink composition using the high jet black carbon black dispersion.

In recent years, with the rise of global environmental problems, the introduction of environmentally friendly paints has been accelerated and replaced with water-based paints in a considerable proportion from the aspect of volatilization of organic solvents and safety and health.
However, in industrial applications such as for automobiles, improvements have been made from the facility side, and it has not been the driving force for replacement only from the health and safety side. In the field of automobile painting, water-based paints are hardly spread except for electrodeposition paints. This is largely due to the lack of regulations and economics such as painting costs. In addition, problems remain in energy consumption and generation of carbon dioxide in the process of manufacturing, painting and baking and curing paints.

  Water-based paints can be used with existing painting methods, have a low solvent content, are non-hazardous materials, have a low risk of fire, have excellent safety and hygiene, and have low solvent emissions. It is a very important paint type among mold paints. However, since water is used as a diluent, there are problems in coating quality and coating film quality. This is due to the fact that the physical characteristics of water evaporative latent heat, surface tension, and dielectric constant are very high compared to organic solvents. The challenge is how to overcome these problems.

  In general, when a colored organic pigment is used as a water-based paint, a dispersion step of mechanically pulverizing aggregated particles is necessary. In order to sufficiently function the original properties of the pigment, it is an essential condition that the pigment particles are finely dispersed in an aqueous medium and the state is stably maintained. The pigment dispersion process overlaps each other through the steps of wetting, grinding, and dispersion. Carbon black, which has been used as a black colorant for thousands of years, has a finer primary particle size compared to commonly used organic pigments such as paints and inks, especially when used in automotive paints. Is extremely difficult to disperse due to its extremely large surface area and small particles among pigments, and it is very difficult to finely disperse. Gloss and transparency and conductivity were lowered.

Early term carbon black is an aggregate of fine spherical particles obtained by incomplete combustion of various hydrocarbons. By skillfully manipulating the reaction conditions in the production furnace, the particle size, agglomeration system, and surface chemical properties are improved. Carbon blacks with a wide variety of different properties can be created.
Since the surface is hydrophobic and has difficulty in dispersion characteristics, a method of increasing the hydrophilicity by treating the surface properties has been used.

As main treatment methods, there are surface functional group addition by oxidation treatment, graphitization of crystal structure by heat treatment, and surface porosity increase by bandit activation treatment with water vapor or carbon dioxide gas.
Conventionally, to obtain a carbon black dispersion with fine particles and high jetness, carbon black having a small primary particle size and a small aggregate is preferably used, and in order to improve dispersibility, the surface of carbon black is used. Oxidized ones, various pigment dispersants such as water-soluble resins and surfactants, and pH adjusters were blended, and energy was applied to finely disperse them in an aqueous medium to improve jetness. However, although carbon black can be finely dispersed to some extent, fine particles cannot be obtained and dispersion stability is also lacking, and coloring power and jet blackness essential for environmentally-friendly automobile paints are insufficient. It had the disadvantage of being inferior in clarity and transparency. Even if fine dispersion can be achieved, various measures are required to keep the pigment in the dispersion stable, and there is a problem that jetness decreases with time. In addition, when non-oxidized carbon black is used, it is more difficult to disperse than acid-treated products, lacks jet-blackness, and there are problems with dispersion stability. There is.

In addition, because it has high jet blackness and sharpness / transparency, carbon black has a small particle size, and when the aggregates are small, coloring power and jet blackness are improved, but fine dispersion is difficult and dispersion stability is extremely poor. In recent years, from the environmental and safety / hygiene aspects, paints are shifting from solvent to water, and automobile paints are also becoming more water-based. However, the appearance and quality standards are maintained even when water-based paints are replaced. Must. In particular, as a black paint, it is extremely difficult to finely disperse highly lipophilic carbon black to achieve dispersion stability, and there is a need to develop a carbon black dispersion with high jetness in such an aqueous dispersion. It has been.

  The present invention solves the above-mentioned conventional problems, and is finely dispersed in a carbon black medium having a small primary particle size and a small aggregate to provide excellent dispersion stability, low viscosity, suitable for fluidity, high jet blackness, Provided are a method for easily producing a carbon black dispersion having high jet blackness, which has sharpness and transparency, has little change over time, and is stable against changes in environmental conditions, and a composition containing the same. For the purpose.

That is, the present invention
(1) DBP oil absorption of 150 ml / 100 g or less, average primary particle size of 15 nm or less, specific surface area of 500 m ² / g or less, and carbon black contained in an acidic or neutral region in an aqueous medium by a pigment dispersant. High jet black carbon black dispersion characterized by fine particle dispersion,
(2) The highly jet black carbon black dispersion according to the above (1), wherein the carbon black is powdery and the coloring power is 90 to 170%,
(3) The high jet black carbon black dispersion according to the above (1) or (2), wherein the average primary particle size of the carbon black is 5 to 15 nm,
(4) The above-mentioned (1), (2) or (3), wherein the carbon black is surface-treated and / or refined and has a pH in an acidic or neutral region. High jet black carbon black dispersion,
(5) The highly jet black carbon black dispersion according to any one of (1) to (4), wherein the carbon black content is 5 to 25% by weight or more,
(6) The above (1) to (5), wherein the pigment dispersant is a water-soluble resin and contains at least one of acrylic acid, a styrene-acrylic acid copolymer and a styrene derivative containing a carboxyl group. High jet black carbon black dispersion according to any one of
(7) The high jet black carbon black dispersion according to any one of the above (1) to (6), wherein the pigment dispersant has an acid value of 50 to 280 mg / 100 mg KOH and a weight average molecular weight of 1000 to 15000,
(8) The highly jet black carbon black dispersion according to any one of (1) to (7) above, wherein the pigment dispersant is a polymer nonionic resin and is contained in an amount of 0.1 to 15% by weight. body,
(9) The highly jet black carbon black dispersion according to any one of the above (1) to (8), wherein the average dispersed particle size of the carbon black is 0.05 μm or less and the pH is 6.0 or more,
(10) DBP oil absorption of 150 ml / 100 g or less, average primary particle diameter of 15 nm or less, specific surface area of 500 m ² / g or less, and pH in an acidic or neutral region, carbon black contained in an aqueous medium by a pigment dispersant A method for producing a highly jet black carbon black dispersion, characterized by having fine particles dispersed therein,
(11) The method for producing a highly jet black carbon black dispersion according to (10), wherein the carbon black is powdery and the coloring power is 90 to 170%,
(12) The method for producing a highly jet black carbon black dispersion according to the above (10) or (11), wherein the average primary particle size of the carbon black is 5 to 15 nm,
(13) The carbon black described in (10), (11) or (12) above, wherein the carbon black has been surface-treated and / or purified and is contained in an acidic or neutral pH range. Method for producing jet-black carbon black dispersion,
(14) The method for producing a highly jet black carbon black dispersion according to any one of (10) to (13), wherein carbon black is contained in an amount of 5 to 25% by weight or more,
(15) Among the above (10) to (14), the pigment dispersant is a water-soluble resin, and contains at least one of acrylic acid, styrene-acrylic acid copolymer and styrene derivative containing a carboxyl group. A method for producing a high jet black carbon black dispersion according to any one of the above,
(16) The high jet black carbon black dispersion according to any one of the above (10) to (15), wherein the pigment dispersant has an acid value of 50 to 280 mg / 100 mg KOH and a weight average molecular weight of 1000 to 15000. Production method,
(17) The highly jet black carbon black dispersion according to any one of (10) to (16), wherein the pigment dispersant is a polymer nonionic resin and the content in the liquid is 0.1 to 15% by weight. Body manufacturing method,
(18) A highly jet black carbon black dispersion obtained by the production method according to any one of (10) to (17),
(19) The highly jet black carbon black dispersion according to the above (18), wherein the average dispersed particle diameter is 0.05 μm or less and the pH is 6.0 or more,
(20) An automotive paint composition containing the highly jet black carbon black dispersion described in (18) or (19) above,
(21) A water-based paint comprising the highly jet black carbon black dispersion according to (18) or (19) above,
(22) An ink composition comprising the highly jet black carbon black dispersion described in (18) or (19) above,
(23) An automotive paint composition comprising the highly jet black carbon black dispersion described in (18) or (19) above,
It is in.

According to the present invention, a paint having high jetness, sharpness and transparency can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described.

The production of the high jet black conductive high concentration carbon black dispersion of the present invention is carried out in an aqueous liquid with a DBP oil absorption of 150 ml / 100 g or less, an average primary particle diameter of 15 nm or less, a specific surface area of 500 m ² / g or less, and a pH of Carbon black contained in an acidic or neutral region is dispersed in an aqueous medium so as to become fine particles with a pigment dispersant, and a paint having high jet blackness, sharpness and transparency can be obtained by the present invention. It is done.

  The highly jet black conductive high-concentration carbon black dispersion of the present invention finely disperses carbon black having the above-mentioned specific properties in an aqueous medium using a pigment dispersant. Compared with the case where carbon black is simply used, there is little secondary aggregation, and the stability over time is excellent, and there is no change in paint or change in jetness of the coating film, and a stable paint with high jetness is obtained.

Carbon black is physically very active, but it is almost chemically inert, has little reactivity with other materials, has high weather resistance, blackness and coloring power, and is economical. Therefore, it is an indispensable pigment for paints as a black pigment, and has been used widely as a coloring material.
Among the pigments, the surface area of carbon black is extremely large and has a structure, so that it has a thixotropy as a fluid property and has a disadvantage of poor flow. Further, the particle surface is hardly wetted, and among the pigments, the surface area is extremely large and the primary particles are small, so that the degree of difficulty in dispersion is high.

In general, carbon black is produced by thermal decomposition of hydrocarbons.
There are two main types: pyrolysis and incomplete combustion. Thermal decomposition methods can be divided into a thermal method using natural gas and an acetylene decomposition method using acetylene gas. The characteristics of acetylene black are that it has excellent crystallinity compared to ordinary carbon black and has a long structure, so it has excellent conductivity, and is used as a conductivity-imparting agent for dry batteries and various rubbers and plastics. ing.
The incomplete combustion method is classified into a gas furnace method using natural gas as a raw material, an oil furnace method using aromatic hydrocarbon oil as a raw material, a contact method, a lamp / pine smoke method, and the like.
The oil furnace method applies continuous pyrolysis in a refractory ceramics reactor and enables stable and efficient mass production of a wide variety of carbon blacks. Therefore, the produced carbon black surface is hydrophobic and generally has a difficulty in dispersion characteristics. The chemical characteristics of the carbon black surface are important factors that affect its optical suitability and flow characteristics. In certain varieties, oxidation treatment is performed as a secondary treatment.

Typical examples of the oxidation treatment include ozone, nitric acid, nitrous acid, sodium hypochlorite, and hydrogen peroxide. A group is generated and the wettability and dispersibility of the carbon black surface are improved.
Conventionally, only the presence of oxygen-containing compounds (surface functional groups) on the particle surface has been discussed. However, when considering the function as a conductivity-imparting agent, the crystallinity of the particle and the porosity of the surface can be adjusted to the surface of the carbon black. It has become necessary to consider it as part of the properties. This surface texture can be imparted by subjecting carbon black to a secondary treatment. As a method, by applying a treatment step such as imparting surface functional groups by oxidation treatment, graphitization by crystal structure by heat treatment in an inert atmosphere, increasing surface porosity by bandit activation treatment with water vapor or carbon dioxide gas, As a new carbon black, it is mass-produced stably and efficiently, and is preferably used as a specific variety.
Typical examples of the oxidation treatment include ozone, nitric acid, nitrous acid, sodium hypochlorite, and hydrogen peroxide. A group is generated and the wettability and dispersibility of the carbon black surface are improved.
Functional groups containing oxygen such as hydroxyl groups, carboxyl groups, and sulfone groups bonded to the surface of carbon black are characterized by the pH of the acidic side of the volatile matter, and it has not been possible to control the type and amount of specific functional groups in the past. Although the range is narrowly limited, it is preferably used for dispersing fine particles in an aqueous medium. Further, a carbon black surface having a sulfone group chemically bonded via a diazo intermediate is more preferable.

In addition to the oxidation treatment, a graft treatment method for polymerizing the monomer based on the surface functional group of carbon black and performing polymer coating has been studied. However, these surface treatment techniques have problems, and in the oxidation treatment, It is difficult to control the type and amount of a specific functional group, and the application range is limited.
In the grafting treatment, if a specific base point such as a quinone group is not sufficiently present on the carbon black surface in advance, the treatment is not performed effectively, and it is difficult to control the graft polymer. In addition, there is a problem that differences are easily caused by the type and amount of surface functional groups in each surface treatment. By applying and developing these carbon black surface treatment technologies, high jet blackness and dispersion ability are achieved. Carbon black has been developed that is high and has low thixotropy and good fluidity.

The contact method is a manufacturing method in which a flame is brought into contact with iron, stone, etc. The channel method and gas black are included, and it is a representative product of the contact method and is collected by bringing a flame into contact with the bottom surface of the channel steel. is there. Carbon black has the smallest particle size and high blackness. However,
Due to economic and environmental pollution problems, it is limited to high-grade colorants that require jetness.
The current mainstream is the oil fanace method, and most carbon blacks for rubber and color are produced by this method, and carbon with a smaller particle diameter and high jet blackness has been developed in recent technology development. Black has been developed. Particularly suitable for automotive paints and high-grade enamel colorants that have the highest blackness and require high jetness, are two types of channel blacks and fanes blacks. Those that have been developed by application are preferably used.

The specific functional group bonded by the surface treatment of the carbon black functions as a dispersant and a surfactant when dispersed in fine particles in an aqueous medium, has an effect of promoting dispersion, and is stable over a long period of time. It also has the effect of maintaining the dispersed state.
Carbon black, which exhibits high jetness, sharpness, and transparency, has DBP (diphthalphthalate) oil absorption as a factor that correlates with its characteristics, and has a reduced particle size, structure development, increased surface area, and porosity. The increase in DBP leads to an increase in the amount of DBP oil absorption, the carbon black filling amount has to be lowered, and the surface area increases to increase the thixotropy by increasing the amount of dispersant required to coat the aggregate surface. Due to the decrease in fluidity, it becomes particularly difficult to finely disperse, jetness, gloss, sharpness, transparency, etc., decrease, form a flow rate, decrease dispersion stability, and uneven It is extremely difficult to obtain a stable high jetness by dispersion or the like.

  The carbon black used in the present invention has an acidic or neutral region produced by a furnace method and surface-treated by chemically bonding a sulfone group to the surface of the carbon black via a diazo intermediate, and has a primary particle size. The carbon black has a small DBP oil absorption, is more porous, has a low structure, and has the above characteristics and has a functional group, and is dispersed in fine particles in an aqueous medium by a pigment dispersant. Dispersing carbon black in fine particles provides high jetness, sharpness, transparency, and gloss, excellent dispersion stability, and stable high jetness even when the environmental conditions change. .

  The carbon black and DBP oil absorption and average primary particle size used in the present invention are preferably small. Those having a small DBP oil absorption and primary particle diameter are difficult to finely disperse and extremely difficult to be dispersed, but are easily refined by the method of the present invention, and are finely dispersible and highly jet black and sharp. This is because good results are obtained in transparency and gloss. In addition, when carbon black is finely dispersed, the DBP oil absorption is 150 ml / 100 g or less so that thixotropy is large, fluidity is lacking, and dispersion stability is not affected. It is necessary to be present, and it is preferably 120 ml / 100 g or less. Further, the average primary particle diameter needs to be 15 nm or less, preferably 12 nm or less, more preferably 10 nm or less. The smaller the particle size and the smaller the aggregate, the higher the jetness, sharpness, transparency, and gloss, but it is difficult to disperse the coarse particles without leaving coarse particles, and the primary aggregate is finally stable. In view of maintaining the average primary particle size, the average primary particle size is preferably 5 nm or more, more preferably 7 nm or more.

  The DBP oil absorption is a value obtained by replacing the void volume in a constant weight of carbon black with a liquid and using the capacity as an index of the structure. Specifically, it refers to the number of milliliters of oil contained per 100 g of carbon black, and the oil is a value measured by an abstract meter using dibutyl phthalate (JIS K 6211 oil absorption amount A method (mechanical method) )).

The primary particles are those in which 1000 to 2000 crystallites are aggregated to form one particle,
The average particle diameter is obtained by measuring primary particles photographed with an electron microscope. Further, a structure in which dozens of these primary particles are bonded to each other is called a structure.
The primary particles are those in which 1000 to 2000 crystallites, which are small spherical components constituting the carbon black aggregate, are aggregated to form one particle, and are measured with an electron microscope. The average particle diameter is obtained by calculating primary particles photographed with an electron microscope. The particle diameter in which this is regarded as a single particle is closely related to the hue and jetness. Its size is 5 to 500 nm. Further, a structure in which dozens of these primary particles are bonded to each other is called a structure.

The specific surface area of the carbon black is a fucker that correlates with the DBP oil absorption and represents the size and fine porosity of the particles, and the high grade has more aggregates per unit weight. In addition, the sharpness, transparency, and glossiness are high, but as the surface area of the carbon black particles increases, the amount of dispersant necessary to coat the aggregate surface increases, greatly affecting the viscosity of the dispersion, and dispersibility and flow. In order to obtain a stable dispersion state, it is necessary to reduce the filling amount of carbon black, and the stability of the carbon black dispersion is reduced, resulting in thickening due to sedimentation and secondary aggregation. Considering this, it is 500 m ² / g or less, preferably 400 m ² / g or less. In consideration of the fact that fine dispersion becomes extremely difficult when the number of particles per unit weight of carbon black is reduced, the specific surface area is preferably 50 m ² / g or more, more preferably 80 m ² / g or more.

  For example, when the pigment dispersant described later is a nonionic or anionic dispersant, the carbon black has a wetting effect in which the medium is adsorbed on the surface of the carbon black and the adhesion between the pigment particles is reduced. And the sterically stabilized carbon black aggregates due to the hydrophobic interaction between the dispersant and the carbon black. Negative charge is given to the aggregate and the aggregate itself repels, so the pH is in the neutral or alkaline region. Are preferred. In the case of an anionic dispersant, if it is in the acidic region, or if it is in a highly alkaline region, it tends to cause hydrolysis. descend. Therefore, the upper limit of the pH is preferably 6.0 or more, more preferably 6.5 or more, and the lower limit is preferably 9.0 or less, more preferably 8.5 or less.

For example, when the pigment dispersant described later is a nonionic or anionic dispersant, the carbon black has a wetting effect in which the medium is adsorbed on the surface of the carbon black and the adhesion between the pigment particles is reduced. , Sterically stabilized carbon black aggregates due to hydrophobic interaction between dispersant and carbon black. Negative charge is applied to aggregates of carbon black, and the pH is included in the weakly acidic or neutral region due to electrostatic attraction that repels the aggregates themselves. Are preferred. In the case of an anionic dispersant, if it is in a strongly acidic region or too high in the alkaline region, it tends to cause hydrolysis. To do. Therefore, the lower limit of the pH is preferably 5.0, more preferably 5.5, and the upper limit is preferably 7.5, and more preferably 7.0.

Further, the carbon black is preferably powdery from the viewpoint of excellent dispersibility, and the coloring power is preferably 90 to 170% from the viewpoint of coloring effect. The smaller the particle size and the larger the specific surface area, the higher the blackness and coloring power. However, considering fine dispersion and dispersion stability, it is 90% or more, preferably 100% or more, and 170% or less, preferably 160%. It is as follows.
Here, the coloring power represents the intensity of color, that is, the degree of hiding with respect to the white pigment, and the coloring power increases as the value increases.
high. A reflectance meter is employed as a method for measuring coloring power, and is defined in Japanese Industrial Standards and ASTM Standards.

In order to prevent the carbon black from becoming too low in viscosity of the resulting dispersion and preventing the dispersion stability from being lost, jet blackness, sharpness, transparency, and gloss, the carbon black content is The dispersion is preferably 5% by weight or more, more preferably 10% by weight or more. Further, in order to eliminate the possibility that the dispersion stability is lowered and it becomes difficult to make fine particles, it is preferably 35% by weight or less, more preferably 30% by weight or less of the carbon black dispersion.

  In the present invention, in order to improve the quality, jet blackness and dispersion stability of the carbon black dispersion, in particular, impurity metal ions such as sodium and potassium described later contained in the obtained carbon black dispersion are used. In order to further reduce the amount, it is preferable to purify the carbon black by washing with ion-exchanged water or water from which impurity metal ions have been removed.

In the production method of the present invention, the specific carbon black is finely dispersed in an aqueous medium with a pigment dispersant.

  As the pigment dispersant used in the present invention, from the viewpoint that carbon black can be stably finely dispersed, a polymeric dispersant having a functional group with high affinity, a water-soluble resin dissolved in water, and Resin dispersible in water can be used alone or in combination. Such resins include styrene-acrylic acid copolymer, styrene-acrylic acid-alkyl acrylate copolymer, styrene-maleic acid copolymer, styrene-maleic acid-alkyl acrylate copolymer, styrene. -Methacrylic acid polymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid-half ester copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyester-based, polyamide-based, polyurethane-based water Water-soluble resins and water-dispersible resins. Of these, styrene-acrylic acid copolymers and styrene-maleic acid copolymers are particularly preferred.

  In addition, carbon black is uniformly finely dispersed, has high jet blackness, sharpness, transparency, and gloss, and stable high jet blackness can be obtained even with respect to dispersion stability and changes in environmental conditions. The oxidation is preferably 50 or more, more preferably 70 or more, and preferably 270 or less, more preferably 230 or less. The weight average molecular weight is preferably 1000 or more, more preferably 1200 or more, and preferably 15000 or less, more preferably 13000 or less.

  The water-soluble resin is preferably neutralized with a basic compound and stably dissolved. For example, alkali metal sodium, potassium hydroxide, aliphatic amine, ethanolamine, diethylamine, triethanolamine, N-methylethanolamine, N-dimethylethanolamine, diisopropanolamine, 2-amino- Examples thereof include organic amines such as 2-methylpropanol, 2-ethyl-2-amino-1,3-propanediol, 2-ethanolamine, triethylamine, and aqueous ammonia. In addition, the neutralization rate is preferably 200% or less, more preferably 50 to 150 so that the salt formed by neutralization is not ionically dissociated and the solubility, water resistance, and re-solubility are maintained well. % Range. Moreover, it is preferable to add the said neutralizing agent as a pH adjuster, and to adjust so that pH of the carbon black dispersion obtained may become an optimal value.

  The amount of the pigment dispersant added is such that the carbon black dispersibility is lowered, resulting in poor dispersion, making it difficult to make fine particles, and the high blackness, sharpness, transparency, gloss, and dispersion stability of the resulting carbon black dispersion. Is preferably 10% by weight or more, and more preferably 12% by weight or more, in order to eliminate the risk that the carbon black dispersion will decrease. In addition, it is difficult to set the viscosity of the carbon black dispersion low, the thixotropy is large, the fluidity is lacking, the dispersion stability is lowered, and the activity ability of impurity metal ions, oxides, nitrides, etc. is further reduced. In order to eliminate the possibility of causing a decrease in the stability of the contained material, it is preferably 30% by weight or less, more preferably 25% by weight or less of the carbon black dispersion.

  The aqueous medium used in the present invention is not particularly limited, but ion-exchanged water and distilled water from which impurity metal ions have been removed are preferable in order to prevent a decrease in dispersion stability.

  The content of the aqueous medium is not particularly limited, and it may be any remaining amount such as other additives usually contained in the high jet black carbon black dispersion in addition to the carbon black and the pigment dispersant.

Furthermore, in the production method of the present invention, the wettability is improved, the adhesion between the pigment particles is reduced, the affinity for facilitating the adsorption of the water-soluble resin to the pigment, and the dispersibility of the carbon black is improved. In order to further improve the high jetness, sharpness, transparency, gloss, and dispersion stability, it is preferable to use a nonionic surfactant, an anionic surfactant and an aqueous solvent.
Furthermore, in the production method of the present invention, the wettability is improved, the adhesion between the pigment particles is reduced, the affinity for facilitating the adsorption of the water-soluble resin to the pigment, and the dispersibility of the carbon black is improved. In order to further improve the high jetness, sharpness, transparency, gloss, and dispersion stability, it is preferable to use a nonionic surfactant, a nonionic polymer, an anionic surfactant, and an aqueous solvent. Nonionic polymers are more preferably used in order to increase the affinity with black and further improve the dispersion stability and hydrophobicity.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene derivative, polyoxyethyleneoxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene Sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, acetylene diol, polyoxyethylene alkylamine, polyoxyethylene alkylphenyl ether modified silicone, etc. Examples thereof include silicone surfactants and fluorine surfactants.
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene derivative, polyoxyethyleneoxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, acetylene diol, polyoxyethylene alkylamine, polyoxyethylene alkylphenyl ether modified silicone, etc. -Non-surfactant, fluorine-based surfactant, etc., and nonionic polymers include high molecular weight polymers such as polyesters, ethoxylated alcohols and ethylene homopolymers. And the like.

  Examples of the anionic surfactant include fatty acid salts, alkyl sulfate esters, alkyl aryl sulfonates, alkyl naphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl dialyl ether terdisulfonates. Alkyl phosphates, polyoxyethylene alkyl aryl ether sulfates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate ester salts, glyceryl borate fatty acid esters, polyoxyethylene glyceryl fatty acid esters, etc. can give.

  The surfactant is more effective by improving the affinity with carbon black, improving the dispersibility of carbon black, and improving high jet blackness, sharpness, transparency, gloss, and dispersion stability and fluidity. In order to make the water-soluble resin easily adsorbed to the pigment and to sufficiently prevent the aggregation of the dispersed particles, the carbon black dispersion obtained contains 0.05% by weight or more, preferably 0.2% by weight or more. It is desirable to make adjustments. In addition, when the amount of the surfactant added is too large, the surfactant is 7% by weight of the carbon black dispersion considering the tendency that the thixotropy is increased, the fluidity and the water resistance / weather resistance are lowered. In the following, it is preferably adjusted so that it is contained in an amount of 5% by weight or less.

  In addition to the surfactant, an aqueous solvent can be added to enhance wettability, such as methyl alcohol, ethyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, n-propyl alcohol, Alcohols such as isopropyl alcohol; Amides such as dimethylformaldehyde and dimethylacetamide; Ketones such as acetone, methyl ethyl ketone, and isobutyl ketone; Tetrahydrofuran, dioxane, ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl Ethers such as ether, triethylene glycol, monomethyl ether, triethylene ethylene glycol, monoethyl ether; ethylene Examples include alcohols such as recall, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, diethylene glycol, polyethylene glycol, polypropylene glycol, and glycerin. Among these, alcohols, glycols, and ketones are preferably used, and can be used alone or in combination of two or more.

  The aqueous solvent is preferably contained in an amount of 5.0% by weight or less of the obtained carbon black dispersion, more preferably, in order to improve wettability with carbon black and improve dispersibility of carbon black. The range is from 0% to 20.0% by weight. In particular, as long as the performance of the obtained carbon black dispersion is not inferior, it is even more preferable that it is completely free from safety and health and environmental problems.

  In addition to the surfactant and the aqueous solvent, if necessary, for example, pigment, wetting and penetrating agent, anti-skinning agent, ultraviolet absorber, antioxidant, cross-linking agent, antiseptic, antifungal agent, viscosity Additives such as a regulator, a pH regulator, a leveling agent, and an antifoaming agent can be appropriately blended within a range not impairing the object of the present invention.

  In the production method of the present invention, there is no particular limitation on the dispersing device used when finely dispersing carbon black in an aqueous medium. As a method of wet grinding, beads such as glass, alumina, zirconia, and modified zirconia are used. The bead mill method used, or the slurry containing pigment without using beads is passed through the high-speed, high-speed bottleneck, then the slurry collides with each other, or collides with the diamond plate, or the ultrasonic method Is preferred. Specifically, examples of the bead mill method include paint shaker, ball mill, attritor, sand mill, par mill, jet mill, spike mill, dry mill, super apex mill, and dyno mill.

  Examples of methods that do not use beads include microfluidizers, nanomizers, and optimizers. Ultrasonic homogenizers and ultrasonic mills are examples of the ultrasonic method, and the bead mill method is preferably used in order to efficiently make the fine particle region. In addition, the pigment, the pigment dispersant, and the water-soluble resin or surfactant are kneaded well in advance with a kneader, two or three roll mill, and then appropriately diluted with water to obtain other additives. May be mixed and dispersed by a bead mill type dispersion apparatus.

  Examples of the media to be dispersed include glass, aluminum, zirconia, modified zirconia, ceramics, etc., in order to avoid contamination of impurity metal ions, oxides, and nitrides, which are factors that reduce dispersion stability, and as much as possible. Particularly preferred are zirconia and modified zirconia, which are excellent in wear resistance. As for the particle size, a small particle size and a high density are important factors in order to make the fine particle region more efficient, and a range of 0.05 mm to 3.0 mm is preferable, and a range of 0.05 mm to 2.0 mm is more preferable. preferable.

  In addition, in order to further improve the dispersion stability of the resulting high jet black carbon black dispersion and obtain a stable particle size distribution, it is desirable to perform centrifugal treatment or filter to remove coarse particles.

  The average particle size of the highly jet black carbon black dispersion obtained in this way is 0.1 μm or less, considering the points of miniaturization and high jet blackness and sharpness, transparency, gloss, smoothness, and dispersion stability. Preferably, it is 0.09 μm or less. In consideration of the possibility that the dispersion becomes excessive and the pigment is re-agglomerated and the long-term stability is lowered, it is preferably 0.01 μm or more, preferably 0.015 μm or more.

The average particle diameter of the high jet black carbon black dispersion obtained in this way is a particle measurement method by a light scattering method, and the fine particles dispersed in the solution have their positions, orientations, and forms due to Brownian motion such as translation and rotation. It changes from moment to moment, and the movement is slower for larger particles and faster for smaller particles. By irradiating these particles with laser light and detecting the scattered light that emerges, the speed of the Brownian motion of the particle is obtained from the fluctuation of the scattering intensity depending on the Brownian motion of the particle, The size.
The average particle size is 0.1 μm or less, preferably 0.09 μm or less, considering the point of miniaturization and high jet blackness, sharpness, transparency, gloss, smoothness, and dispersion stability. desirable. In consideration of the possibility that the dispersion becomes excessive and the pigment is re-agglomerated and the long-term stability is lowered, it is preferably 0.01 μm or more, preferably 0.015 μm or more.

  The high jet black carbon black dispersion has a low viscosity, but when the amount of the carbon black dispersion mixed with a fixing agent such as a water-soluble resin or an emulsion is limited, for example, the viscosity of the obtained ink composition The viscosity at 25 ° C. is preferably 100 mPa · S or less, and preferably 90 mPa · S or less, considering that the gloss and smoothness of the coated surface are reduced and the occurrence of peeling is observed. . In addition, when the ink composition is applied by a wet coating method such as an air spray method, an airless spray method, electrostatic coating, dipping, or a roll coater, the suitability for coating is reduced, and a uniform coated surface is obtained. In view of this, it is desirable that the viscosity at 25 ° C. is 1.0 mPa · S or more, preferably 1.5 mPa · S or more.

  As described above, the high jet black carbon black dispersion of the present invention is obtained by finely dispersing carbon black in an aqueous medium, having excellent dispersion stability, low viscosity, suitable for fluidity, and high jet blackness and sharpness, transparency, Of course, since it has a glossy and uniform coating surface with high smoothness, it can be suitably used for water-based paints and water-based automotive paints.

  The water-based paint and automotive paint composition of the present invention contain the highly jet black carbon black dispersion.

  In the water-based paint and the automobile paint composition, the content of the high jet black carbon black dispersion is 2% by weight in order to impart any jet black sharpness, transparency, and gloss to the resulting composition. As mentioned above, it is desirable to adjust so that it may contain 5 weight% or more preferably. Further, in order to prevent the coating strength of the resulting composition from becoming too low and the finished appearance of the surface, such as the occurrence of cracks, from being deteriorated, it is desirable to be 40% by weight or less, preferably 35% by weight or less.

  In addition to the high jet black carbon black dispersion, the water-based paint and automotive paint composition of the present invention include, for example, a film-forming resin, a crosslinking agent, a leveling agent, a surfactant, a viscosity modifier, a filler, and a pH adjuster. In general, those used in water-based paints and automotive paint compositions such as an agent can be appropriately blended.

Examples of the resin film-forming resin include natural proteins such as casein, gelatin, albumin and gum arabic, synthetic rubbers such as isoprene rubber latex, butadiene rubber latex and chloroprene rubber latex, alginic acid, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, Polyvinyl alcohol, polyvinyl ether, polyvinyl pyrrolidone, aromatic amide, acrylic resin, melamine resin, alkyd resin, styrene acrylic resin, styrene maleic resin, polyester resin, urethane resin, vinyl acetate resin, silicone resin, epoxy resin, phenol -Synthetic polymers such as resin, fluorine resin, photosensitive resin, ultraviolet curable resin, thermosetting resin and the like. In addition, this resin coating film-forming resin can be emulsified by emulsification and suspension polymerization by dispersing a monomer in an aqueous medium. These can be used alone or in admixture of two or more, and are selected and used depending on the application. Moreover, it is preferable that the content is 20 to 90 weight% of a water-based coating material and a motor vehicle coating composition.

  Examples of the cross-linking agent that promotes the reaction of the resin film-forming resin and improves water resistance, solvent resistance, and film strength include melamine resin, benzoguanamine resin, urea resin, aziridine compound, carbodiimide resin epoxy resin And aminoformaldehyde resins, polyvalent isocyanate compounds, polyhydroxy compounds, polyvalent amine compounds, organic peroxides, and the like. These may be used alone or in admixture of two or more. Further, the content thereof is 0.01 to 15% by weight or less, preferably 0.01 to 10% by weight or less of the water-based paint or the automobile paint composition.

  Examples of the leveling agent include silicone-based, fluorine-based and the like, and as silicone-based, dimethyl silicone oil, methylphenyl silicone oil, alkyl-modified silicone, alkoxy-modified silicone, Oxyalkyl-modified silicones, glycol-modified silicones, polyether-modified silicones, polyether-modified silicones, fatty acid ester-modified silicones, fluorine-based compounds such as fluorocarbon compounds, fluorine-based silicones These may be used alone or in combination of two or more.

  Examples of the surfactant include an anionic surfactant such as a fatty acid salt, an alkyl sulfate ester salt, an alkyl aryl sulfonate, an alkyl naphthalene sulfonate, a dialkyl sulfonate, a dialkyl sulfosuccinate, and an alkyl dialyl ether. Terdisulfonate, alkyl phosphate, polyoxyethylene alkyl aryl ether sulfate, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt and the like.

  Examples of amphoteric surfactants include lauryl dimethylamine oxide, lauryl carboxymethyl hydrodoxy ethyl derived from higher alkyl amines, and betaine type compounds such as lauryl betaine and stearyl betaine.

  Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene derivatives, polyoxyethyleneoxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acids Examples thereof include esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and fluorosurfactants. Fluorosurfactants include perfluoroalkyl carboxylic acids, perfluoroalkyl phosphate esters, perfluoroalkyl betaines, perfluoroalkylamine oxides, perfluoroalkyl ethylene oxide adducts, and the like. Or 2 or more types can be mixed and used. The content is considered that when a leveling agent or surfactant is added to the coating solution, the surface tension is lowered, the permeability is improved, and coating defects such as repellency and coating unevenness can be prevented. Then, it is desirable that it is 0.0001 to 10 weight%.

  Examples of the viscoelasticity adjusting agent include polyether resins, modified polyacrylic sulfonates, urethane modified polyether resins, modified polyacrylic acid sodium acid compounds, modified polyacrylic emulsions, and the like. These can be used alone or in admixture of two or more.

  Examples of the filler include silicon dioxide, alumina, zinc white, potassium titanate whisker, aluminum flake, titanium mica, calcium carbonate, barium sulfate, barium carbonate, kaolin, barita, clay and other metal oxides, composite metal oxides In order to prevent a decrease in viscosity and poor gloss, they can be used alone or in admixture of two or more.

As another additive, in the present invention, water having a relatively large surface tension is used as a solvent, and an aqueous solvent can be appropriately blended in order to further increase the permeability. Examples of the aqueous solvent include alcohols such as methyl alcohol, ethyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, n-propyl alcohol, and isopropyl alcohol; amides such as dimethylformaldehyde and dimethylacetamide; Ketones such as acetone, methyl ethyl ketone, isobutyl ketone; tetrahydrofuran, dioxane, ethylene glycol methyl ether,
Ethers such as ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, triethylene glycol, monomethyl ether, triethylene ethylene glycol, monoethyl ether; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1, 2, 6-hexanetriol, thiodiglycol,
Examples include multi-class alcohols such as diethylene glycol, polyethylene glycol, polypropylene glycol, and glycerin. Among these aqueous solvents, alcohols and glycols are preferably used, and these may be used alone or in combination of two or more. it can.

In addition, a pH adjusting agent can be used to adjust the pH of the water-based paint or automobile paint composition to obtain the viscosity stability of the paint composition. Examples of the pH adjuster include sodium and potassium hydroxides, which are alkaline metals, aliphatic amines, ethanolamines, ethanolamines, triethanolamines, N-methylethanolamine, N-dimethylethanolamine, and diisopropanol. Examples thereof include organic amines such as amine, 2-amino-2-methylpropanol, 2-ethyl-2-amino-1,3-propanediol, 2-ethanolamine, triethylamine, and aqueous ammonia.
Further, an antifoaming agent can be appropriately blended in order to prevent the generation of bubbles during the production of water-based paints and automobile paint compositions and the production of foam.

  There is no particular limitation on the method for obtaining the water-based paint and automotive paint composition of the present invention, for example, there is no particular limitation on the method of adjusting the blending amount as appropriate, for example, the conductive high-concentration carbon black for electrophotography with the blending amount adjusted appropriately In addition to stirring and mixing with a kneader or disperser, high-speed dispersion, resin coating film forming resin, crosslinking agent, viscosity modifier, surfactant, leveling agent, filler, aqueous solvent, pH adjuster, etc. It can be performed by a disperser.

The aqueous paint and automotive paint composition thus obtained can be used as an automotive intermediate coating by a conventionally known method. Moreover, it can be applied not only to the intermediate coating film but also to the undercoating film and the base coating film.
Furthermore, it can use suitably as a water-based coating material and an ink composition according to the objective in each field | area and a required characteristic.

  Next, the highly jet black carbon black dispersion of the present invention, the production method thereof, and the composition comprising the same will be described in more detail based on examples, but the present invention is not limited to such examples.

Example 1
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions 14% by weight, and as a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight A dispersion mill base was obtained by adding 1.5% by weight of dimethylethanolamine, 0.1% by weight of a preservative, 0.1% by weight of a wetting and penetrating agent and 100% by weight of ion-exchanged water. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a high jet black carbon black dispersion. The metals (Na and K) contained in the obtained high jet black carbon black dispersion were subjected to elemental analysis using an atomic absorption photometer (manufactured by Hitachi, Ltd., Z-8230).
The results are shown in Table 1.

  As characteristics of the highly jet black carbon black dispersion obtained in the present invention, the viscosity, average particle diameter, pH, jet blackness and dispersion stability were examined according to the following methods. In addition, as physical properties of the coating film formed using the high jet black carbon black dispersion, brightness / chroma (L * .a * .b *) and specular gloss were examined by the following methods. The results are shown in Tables 1 and 2.

The coating film is obtained by mixing a highly jet black carbon black dispersion into an acrylic-urethane copolymer emulsion so as to be uniform (the content of carbon black (CB / solid content) relative to the solid content of the ink composition,
4.0 wt%), and the obtained ink composition was applied to a steel plate for automobiles (JISG3303: manufactured by Nippon Test Panel Co., Ltd.) with an applicator 10 mil and dried. . (Dry film thickness: 15 μm)

(1) Viscosity Using a cone type TV-20L viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity (mPa · S) of the carbon black dispersion immediately after preparation was measured at 25 ° C.
The low viscosity of the carbon black dispersion means that the carbon black dispersion having a carbon black content of 14% by weight is 10 mPa · S or less.

(2) Average particle size The average particle size (μm) was measured using a laser light diffusion type particle size distribution analyzer (Leeds and North Rup, Microtrac UPA particle size distribution analyzer). . However, the volume cumulative 50% diameter value is shown.
The Microtrac UPA particle size distribution meter is a method for determining the particle diameter of the fine particles from the amount of change in the frequency of light returning from the particles by irradiating the fine particles moving with Brownian light.
In particular, since carbon black is generally formed by agglomerating fine particles, the average particle size of the carbon black dispersion is larger than the primary particle size of carbon black. Therefore, the carbon black dispersion is very finely dispersed when the average particle diameter is 0.05 μm or less with respect to the carbon black dispersion having a carbon black content of 14% by weight.

(3) pH
The pH (unitless) was measured using a pH meter (available from Electrochemical Instruments [PHL-10 type]).
The pH of the carbon black dispersion is expressed as an index of the hydrogen ion concentration [H +], where pH is 7 neutral, acidic when pH is less than 7, and alkaline when pH is greater than 7. When acidic and alkaline solutions are diluted with water, the pH is close to 7.

(4) Lightness / Saturation Lightness / saturation (L * a * b *) was measured using a color difference meter (Spectraflash 600PLUS-CT, manufactured by datacolor Co., Ltd.) The values of the CIE 1976 color system are shown.
The lightness / saturation (L * a * b *) is a color solid (color space) in which uniform distances (psychological distance feeling) between colors that appear to be the same color are psychologically equal. ), Called CIE 1976 (L * a * b *) color system, JIS
Z 8729. The lightness is L * “lightness index”, a * b * indicates the position corresponding to hue and saturation, and the hue called “chromaticness index” is from red to yellow when a * b * is positive, Conversely, if it is negative, it becomes blue. A coating film having high jetness means that the lightness (L *) is 2.0 or less.

(5) Dispersion stability 100 ml of carbon black dispersion was taken into an easy bottle (Nikko Co., Ltd.) and allowed to stand at room temperature and 50 ° C. for 10 days. The viscosity at 25 ° C. was measured using a meter, compared with the viscosity immediately after preparation measured in (1) above, and evaluated based on the following evaluation criteria.

(Evaluation criteria)
(Double-circle): There is no precipitation of carbon black, it is a very good state without jet-blackness fall, a viscosity change, and the average particle diameter increase.
◯: There is almost no sedimentation of carbon black, and there is no significant change in jetness reduction, viscosity change, and average particle size increase, and it is in a good state.
(Triangle | delta): There exists considerable sedimentation of carbon black, there exists a jet black fall, a viscosity increase, and the average particle diameter increase, and it is a bad state.
X: Sedimentation of carbon black is significant, and jet blackness is decreased, viscosity is increased, and average particle size is extremely increased.

(6) Specular Gloss The value measured at an angle of 60 ° using VG 2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) is shown. The specular gloss is based on a black glass standard plate (refractive index: 1.567), and the gloss is 100. JIS
Z 8741. High gloss refers to a case where the gloss level exceeds 70.

Example 2
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions 14% by weight, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 9.7 as a pigment dispersant % By weight, acrylic resin (acid value 7-four, weight average molecular weight 10,000) 13.0% by weight, polymer polyester (nonionic: weight average molecular weight 100,000) 0.4% by weight, dimethylethanolamine 1.5% by weight %, Preservative 0.1% by weight, wetting and penetrating agent 0.1% by weight, and ion-exchanged water are added so that the total amount becomes 100% by weight. To give a dispersion mill base. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion. About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using it were examined in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Example 3
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions 14% by weight, alcoholic ethylene polymer (nonionic: weight average molecular weight 4600) 8.7% by weight as a pigment dispersant, alcoholic alkylene oxide (Non-ionic: HLB15.2, cloudy 97) 3.9% by weight, ethylene glycol monobutyl ether 3.0% by weight, dimethylethanolamine 0.1% by weight, preservative 0.1% by weight, wetting penetrant 0. A dispersion mill base was obtained by adding 1% by weight and ion exchanged water to a total amount of 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion. About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using it were examined in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Example 4
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions, 14% by weight. As pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 12% by weight. , Alcohol-based ethylene polymer (nonionic: weight average molecular weight 4600) 12% by weight, ethylene glycol monobutyl ether 3.0% by weight, dimethylethanolamine 1.2% preservative 0.1% by weight, wetting penetrant 0.1 A dispersion mill base was obtained so that the total amount was 100% by weight with addition of ion exchange water. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion. About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

Example 5
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions 14% by weight, and as a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight A dispersion mill base was obtained by adding 2.0% by weight of ammonia water, 0.1% by weight of preservative, 0.1% by weight of the wetting and penetrating agent and 100% by weight of ion-exchanged water. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a high jet black carbon black dispersion. About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

Example 6
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions, 14% by weight. As a pigment dispersant, a copolymer of an acrylic polymer and a nonionic active substance (acid value 2.0, weight average molecular weight 4500). 17.5 wt%, dimethylethanolamine 1.3 wt preservative 0.1 wt%, wetting and penetrating agent 0.1 wt%, and ion-exchanged water to make the total amount 100 wt% Yeah. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion. About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

(Comparative Example 1)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions 14% by weight, and as a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight A dispersion mill base was obtained by adding 1.5% by weight of dimethylethanolamine, 0.1% by weight of a preservative, 0.1% by weight of a wetting and penetrating agent and 100% by weight of ion-exchanged water. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion was low in dispersibility and jet blackness as compared with that of Example 1, and lacked dispersion stability, and a slight precipitation of carbon black was observed after 10 days at room temperature.

  About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

(Comparative Example 2)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powder) Washed and filtered with ion-exchanged water to remove impurity metal ions, 14% by weight. As pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 20% by weight. A dispersion mill base was obtained by adding 1.5% by weight of dimethylethanolamine, 0.1% by weight of a preservative, 0.1% by weight of a wetting and penetrating agent and 100% by weight of ion-exchanged water. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a high jet black carbon black dispersion.
However, the obtained carbon black dispersion lacked dispersion stability as compared with that of Example 1, and thickened and increased in size after 10 days at room temperature.

  About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

(Comparative Example 3)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powdery) 14 As a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight, dimethylethanolamine 1.5% by weight, preservative 0.1% by weight, A dispersion mill base was obtained by adding 0.1% by weight of the wetting and penetrating agent and ion-exchanged water so that the total amount became 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion had a slightly higher viscosity than the stability of Example 1, lacked dispersion stability, increased viscosity and increased particle size after 10 days at room temperature, and pH. Because of the high viscosity, the viscosity stability of the coating film coating solution was lacking and jet jetness was also lowered.

About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The physical properties of the coating films whose results are shown in Tables 1 and 2 were examined in the same manner as in Example 1. The results are shown in Tables 1 and 2.

(Comparative Example 4)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 583 m ² / g (BET method), DBP oil absorption 95 ml / 100 g, pH 2.8, coloring power 135%, powdery) 14 As a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight, dimethylethanolamine 2.2% by weight, preservative 0.1% by weight, A dispersion mill base was obtained by adding 0.1% by weight of the wetting and penetrating agent and ion-exchanged water so that the total amount became 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion lacked dispersibility as compared with that of Example 1, and a 10 μ filter treatment was slightly difficult. In addition, the dispersion stability was lacking, and after 10 days at room temperature, the pH decreased, and thickening and granulation were observed.

  About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

(Comparative Example 5)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 583 m ² / g (BET method), DBP oil absorption 95 ml / 100 g, pH 2.8, coloring power 135%, powdery) 14 As a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 9.7% by weight, acrylic resin (acid value 74, weight average molecular weight 10,000) 13.0 % By weight, high molecular weight polyester (nonionic: weight average molecular weight 100,000) 0.4% by weight, dimethylethanolamine 2.2% by weight, preservative 0.1% by weight, wetting penetrant 0.1% by weight, and Ion exchange water was added to obtain a dispersion mill base so that the total amount was 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.1 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion lacked dispersibility as compared with that of Example 1, and a 10 μ filter treatment was slightly difficult. Also, the dispersion stability was lacking, and after 10 days at room temperature, the viscosity was increased greatly, the granulation increased, and the fluidity was lost.

  About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Tables 1 and 2.

(Comparative Example 6)
Carbon black (furnace black, pigment black 7, average primary particle size 0.008 μm, specific surface area 385 m ² / g (BET method), DBP oil absorption 88 ml / 100 g, pH 7.1, coloring power 105%, powdery) 14 % By weight, 20% by weight styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000), 2.5% by weight aqueous ammonia, 0.1% by weight preservative, and wetness A dispersion mill base was obtained by adding 0.1% by weight of a penetrant and ion-exchanged water to a total amount of 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion. The obtained carbon black dispersion is relatively good in dispersibility as compared with that of Example 1, but lacks dispersion stability, and after 10 days at room temperature, thickening and grain increase are observed. It was.

About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using it were examined in the same manner as in Example 1. The results are shown in Tables 1 and 2.
However, the obtained carbon black dispersion lacks dispersibility, is very difficult to filter by 1 μm, lacks dispersion stability, and increases in viscosity and particle size after one day at room temperature. The liquidity has also disappeared.

(Comparative Example 7)
Carbon black (channel black, pigment black 7, average primary particle size 0.013 μm, specific surface area 460 m ² / g (BET method), DBP oil absorption 150 ml / 100 g, pH 2.5, coloring power 112%, powdery) 14 As a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight, dimethylethanolamine 2.2% by weight, preservative 0.1% by weight, A dispersion mill base was obtained by adding 0.1% by weight of the wetting and penetrating agent and ion-exchanged water so that the total amount became 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion lacks dispersibility compared to that of Example 1, is difficult to filter by 10 μm, and lacks dispersion stability, and after 10 days at room temperature. Viscosity greatly increased, granulation increased, and fluidity was lost.
Lack of dispersibility, low viscosity, high viscosity, lack of dispersibility, 1μ filter treatment is very difficult, lack of dispersion stability, increase after 10 days at room temperature Viscosity and particle size increase and fluidity is lost.

About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Table 1.
The obtained carbon black dispersion has low jetness and gloss as compared with that of Example 1, has a high viscosity, lacks dispersibility, and is very difficult to filter by 1 μm. The dispersion stability was poor, and after 10 days at room temperature, the viscosity increased and the particle size increased and the fluidity was lost.

(Comparative Example 8)
Carbon black (Furness black, Pigment black 7, Average primary particle size 0.024 μm, Specific surface area 125 m ² / g (BET method), DBP oil absorption 110 ml / 100 g, pH 8.0, coloring power 124%, powder) As a pigment dispersant, styrene-α-methylstyrene-acrylic acid copolymer (acid value 160, weight average molecular weight 8000) 28% by weight, dimethylethanolamine 1.2% by weight, preservative 0.1% %, 0.1% by weight of the wet penetrant, and ion-exchanged water were added to obtain a dispersion mill base so that the total amount was 100% by weight. This was pre-stirred with a disperser (1000 rpm) for 1 hour, and then dispersed with a wet pulverizer filled with 85% zirconia beads having a diameter of 0.5 mm at a peripheral speed of 7 m / sec and a residence time of 15 minutes, and then a peripheral speed of 10 m. / Sec at a residence time of 30 minutes, and the resulting dispersion was filtered through a 350 mesh screen. Further, coarse particles that could not be dispersed by 1 μm filter treatment were removed and adjusted to a solid content concentration of 21.0% by weight to obtain a highly jet black carbon black dispersion.
The obtained carbon black dispersion lacked dispersibility and jet blackness as compared with that of Example 1, and it was difficult to perform 10 μm filter treatment. Also, the dispersion stability was lacking, and precipitation of carbon black was observed after 10 days at room temperature.

  About the metal (Na and K) contained in the obtained highly jet black carbon black dispersion, the amount of the metal, its characteristics, and the physical properties of the coating film formed using this were examined in the same manner as in Example 1. . The results are shown in Table 1.

  From the results shown in Table 1, in the carbon black dispersions obtained in Examples 1 to 6, Na was not more than about 25 mg / kg and K was not more than 135 mg / kg. It can be seen that, in addition to being extremely small, the viscosity is lower than 10 mPa · S, low viscosity suitable for fluidity, and dispersion stability is also very good. Moreover, all of these carbon black dispersions have an average particle size of less than 0.04 μm and are very finely dispersed, and have no secondary aggregation and high storage stability. Also, since the pH is neutral to weakly alkaline, compatibility with the coating film resin is good, and there is little change in viscosity over time, and it is suitable for obtaining paints with stable high jetness even when the environmental conditions change. It turns out that it has a characteristic.

  Further, the coating films in Examples 1 to 6 formed from the excellent carbon black dispersion as described above have extremely high jet blackness and sharpness, with lightness: (L *) of 2.0 or less. It can be seen that a high gloss exceeding 70 is obtained in the specular gloss (60 °). Further, it can be seen that since the carbon black dispersion is finely dispersed, a uniform surface shape with high smoothness can be obtained.

In contrast, the carbon black dispersions obtained in the comparative examples all have an average particle diameter exceeding 0.05 μm, are not finely dispersed, and are inferior in dispersion stability. I understand that.
It can be seen that Comparative Example 2 is inferior in dispersion stability although it is finely dispersed with low viscosity.
Further, in the carbon black dispersions of Comparative Examples 3 and 6 to 8, the contents of Na and K, which are impurity metal ions, exceed 150 mg / kg and 300 mg / kg, respectively. It can be seen that there is a great adverse effect on jetness reduction and dispersion stability.

  The highly jet black carbon black body of the present invention solves the above-mentioned conventional problems, and is finely dispersed in a carbon black medium having a small primary particle size and small aggregates, and has excellent dispersion stability and viscosity. Therefore, it is suitable for fluidity, has high jetness, sharpness, and transparency, and has high jetness that has little change with time and is stable against changes in environmental conditions. Moreover, this highly jet black carbon black body can be easily obtained by the production method of the present invention.

  The excellent high jet black carbon black dispersion as described above can be suitably used in various compositions, and the automotive paint composition, the high jet black water-based paint and ink of the present invention containing the high jet black carbon black body. The composition has excellent physical properties.

Claims (23)

Carbon black having a DBP oil absorption of 150 ml / 100 g or less, an average primary particle size of 15 nm or less, a specific surface area of 500 m ² / g or less and a pH in an acidic or neutral region is dispersed in an aqueous medium by a pigment dispersant. A highly jet black carbon black dispersion characterized by that.   The highly jet black carbon black dispersion according to claim 1, wherein the carbon black is powdery and has a coloring power of 90 to 170%.   The highly jet black carbon black dispersion according to claim 1 or 2, wherein the carbon black has an average primary particle diameter of 5 to 15 nm.   The highly jet black carbon black dispersion according to claim 1, 2 or 3, wherein the carbon black has been subjected to surface treatment and / or purification, and has an acidic or neutral pH range.   The highly jet black carbon black dispersion according to any one of claims 1 to 4, wherein the carbon black content is 5 to 25 wt% or more.   The pigment dispersant is a water-soluble resin, and contains any one or more of acrylic acid, a styrene-acrylic acid copolymer and a styrene derivative containing a carboxyl group. High jet black carbon black dispersion.   The high jet black carbon black dispersion according to any one of claims 1 to 6, wherein the pigment dispersant has an acid value of 50 to 280 mg / 100 mg KOH and a weight average molecular weight of 1000 to 15000.   The highly jet black carbon black dispersion according to any one of claims 1 to 7, wherein the pigment dispersant is a polymer nonionic resin and is contained in an amount of 0.1 to 15% by weight.   The high jet black carbon black dispersion according to any one of claims 1 to 8, wherein an average dispersed particle size of the carbon black is 0.05 µm or less and a pH is 6.0 or more. DBP oil absorption of 150 ml / 100 g or less, average primary particle diameter of 15 nm or less, specific surface area of 500 m ² / g or less, and pH in an acidic or neutral region, carbon black contained in a neutral region is dispersed in an aqueous medium by a pigment dispersant. A method for producing a highly jet black carbon black dispersion, characterized by comprising:   The method for producing a highly jet black carbon black dispersion according to claim 10, wherein the carbon black is powdery and has a coloring power of 90 to 170%.   The method for producing a highly jet black carbon black dispersion according to claim 10 or 11, wherein an average primary particle diameter of the carbon black is 5 to 15 nm.   13. The production of a highly jet black carbon black dispersion according to claim 10, 11 or 12, wherein the carbon black is surface-treated and / or purified and is contained in an acidic or neutral pH range. Method.   Carbon black is contained 5 to 25weight% or more, The manufacturing method of the highly jet black carbon black dispersion | distribution in any one of Claims 10-13 characterized by the above-mentioned.   The pigment dispersant according to any one of claims 10 to 14, wherein the pigment dispersant is a water-soluble resin and contains at least one of acrylic acid, styrene-acrylic acid copolymer and styrene derivative containing a carboxyl group. Method for producing jet-black carbon black dispersion.   The method for producing a highly jet black carbon black dispersion according to any one of claims 10 to 15, wherein the pigment dispersant has an acid value of 50 to 280 mg / 100 mg KOH and a weight average molecular weight of 1000 to 15000.   The method for producing a highly jet black carbon black dispersion according to any one of claims 10 to 16, wherein the pigment dispersant is a polymer nonionic resin and the content in the liquid is 0.1 to 15% by weight. A highly jet black carbon black dispersion obtained by the production method according to claim 10.   The highly jet black carbon black dispersion according to claim 18, wherein the average dispersed particle diameter is 0.05 µm or less and the pH is 6.0 or more.   An automotive paint composition comprising the highly jet black carbon black dispersion according to claim 18 or 19.   An aqueous paint comprising the highly jet black carbon black dispersion according to claim 18 or 19.   An ink composition comprising the highly jet black carbon black dispersion according to claim 18 or 19.   An automotive paint composition comprising the highly jet black carbon black dispersion according to claim 18 or 19.