JP2000017188A - Aqueous carbon black dispersion and aqueous ink using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous carbon black dispersion exhibiting excellent dispersion stability, even when left at a high temperature for a long time, capable of inhibiting the clogging of nozzles and pen tips, and useful as an aqueous ink for ink jet printers, writing tools, etc., by limiting the iron content of the aqueous dispersion to a specific value or smaller. SOLUTION: This aqueous dispersion is obtained by dispersing (B) carbon black in (A) an aqueous medium. Therein, the iron content of the aqueous dispersion is controlled to <=5 ppm, and, if necessary, the silicon content is also controlled to <=5 ppm. The aqueous dispersion is preferably controlled to pH 5-10 and a component B content of 0.5-50 wt.%. The component B is preferably subjected to an ozone oxidation treatment in the presence of water, and has total acidic groups of >=3 μequ/m2, an active hydrogen content of <=2 mmol/g, a particle diameter of 10-30 nm and a DBP oil absorption volume of 50-180 cc/100 g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to carbon black, which is preferably used as a pigment for inks for ink jet and writing inks, an aqueous dispersion containing carbon black in an aqueous medium, and an aqueous ink.

[0002]

2. Description of the Related Art Ink-jet recording has characteristics such as low noise during recording, color printing, high-speed printing, printing on plain paper and high quality. It is widely used for computer printing, regardless of the type. There are various types of this ink jet printing, a method of discharging ink in thin nozzles in the print head by electrostatic energy, and a method of flowing a current to a tropical zone in the print head and generating bubbles by generating heat. A method of performing printing by ejecting ink from a nozzle.

[0003] As an ink used for such an ink jet recording, an aqueous ink in which a dye is dissolved or dispersed in water has conventionally been used. Such water-based inks are also used for writing instruments such as fountain pens and ballpoint pens. The performance required for the recording ink used in these applications includes the following items.

[0004] (1) No bleeding of printed or written matter (2) No fading of printed or written matter due to light or heat (3) Even if left for a long time, the nozzle or pen tip in the recording head No clogging (4) Good storage stability (5) Low ink viscosity

[0005] As described above, conventionally, inks for these uses have been used in which a dye is dissolved or dispersed in water as a colorant. However, when a dye is used, bleeding tends to appear on printed or written matter. Due to the problem of fading due to light, inks using carbon black as a black pigment have recently attracted attention. In a dye-based inkjet ink composition, some additives are required to satisfy various conditions such as ink ejection conditions, long-term storage stability, image clarity and density during recording, and the like. Since these additives and the dyes used also contain various impurities, clogging occurs at the tip of the ink jet printer head or in the ink flow path, or precipitates are generated during long-term storage. And so on. Further, in the ink jet system using thermal energy, there is a problem that a deposit is generated on the surface of the heating element.

Although the causes of these problems have not been completely elucidated, for example, Japanese Patent Application Laid-Open No. H8-31377 discloses that the presence of silicon in a certain amount or more causes precipitation during long-term storage, and And the formation of deposits on the surface of the heat-generating element, and precipitates are generated during storage, which strongly suggests an interaction between silicon and the dye. Dyes or various additives have been estimated as sources of these impurities. Regarding the total amount of iron and silicon,
In JP-A-8951, silicon and iron are related to the deposition of foreign matter on the surface of a heating head in an ink jet system using thermal energy, and it is speculated that the source of these impurities is from the dye itself or water used. . Dyes are organic substances and weak to heat, and together with these impurities such as silicon and iron, carbonize on the heating element,
It is conceivable to deposit.

On the other hand, the present inventor has used carbon black as a pigment, and in particular, using carbon black having a specific surface functional group in a predetermined amount,
It has good dispersion stability in an aqueous medium and achieves high printing density and water resistance (Japanese Patent Application No. 8-3475).
29). This is because carbon black oxidized with ozone in the presence of water and the amount of all acidic groups is 3 μequ / m
Disperse ^two or more carbon blacks in an aqueous medium,
A water-based ink such as an ink-jet ink is prepared. In addition, the above-mentioned specific carbon black is an epoch-making one that can obtain a good dispersion state in an aqueous medium without adding a dispersant. Therefore, for example, in the case of using this specific carbon black, in the aqueous ink composition using carbon black as a pigment, as described above, the problem of using a dye is solved, and therefore, the dye as described above No attention has been paid to the presence of impurities that are problematic in the aqueous based ink composition, and no effort has been made to reduce these impurities.

[0008]

By the way, when an aqueous dispersion is prepared using carbon black having a total acidic group of 3 μequ / m ² or more disclosed in Japanese Patent Application No. 8-347529 developed by the present inventors. Although it is possible to obtain a good dispersibility, while studying the improvement of the ejection stability of the aqueous ink using this, surprisingly, it is necessary to reduce the amount of iron and silicon to a certain amount or less. They have found that they contribute to stability, and have reached the present invention. That is, the present invention
It is present in an aqueous carbon black dispersion having a total content of iron and silicon of 10 ppm or less.

[0009]

DETAILED DESCRIPTION OF THE INVENTION First, the carbon black used in the present invention is not particularly limited, and any carbon black including carbon black conventionally used as a pigment for inks can be used. The carbon black that can be used in the present invention is not particularly limited, but as a particularly preferred carbon black, various surface treatments, particularly in an aqueous medium even without the presence of a dispersant by imparting an acidic functional group to the surface by oxidation treatment. Oxidized carbon black, which can be dispersed, is preferred. This is probably due to the interaction between acidic functional groups such as carboxyl groups present on the surface of these oxidized carbon blacks and silicon, iron or silicon (atoms, ions or compounds containing these elements). Since the effects of the present invention have some relation, it is presumed that extremely remarkable effects can be obtained when the present invention is carried out using the oxidized carbon black.

The particle size of the carbon black is not limited, but is preferably 100 nm or less, more preferably 30 nm or less, because the sedimentation of the particles is particularly suppressed. Further, since sulfur and sulfur compounds in carbon black are oxidized by an oxidizing agent to form sulfate ions in a solution, it is desired that the amount is as small as possible. 0.1% by weight or less is preferred. In order to reduce the sulfur content, it is possible to use an aromatic hydrocarbon used as a raw material for carbon black, a liquid hydrocarbon used as a fuel, or a low hydrocarbon content gaseous hydrocarbon as a gaseous hydrocarbon. Although halogen ions are mainly chlorine ions, they are derived from cooling water that stops the reaction during carbon black production.To reduce this, pure water is used as cooling water, and halogen ions are contained in carbon black. Halogen ions can be reduced. It is considered that nitrate ions are mainly derived from NOx generated in a combustion gas used when producing carbon black. Extreme reduction of NOx in the combustion gas is difficult with current technology.

The amount of sulfur in carbon black can be determined, for example, by precisely weighing 0.1 g of carbon black and using SUSU manufactured by Vestuf.
LMHOGRAPH12A ". The amount of halogen ions in the carbon black can be measured by TOX-150 manufactured by Mitsubishi Chemical. The following is particularly preferred as a method for oxidizing carbon black. That is, after suspending carbon black in water, oxidation is performed by reacting with an oxidizing agent. The amount of water is
95: 5 to 0.5 in the ratio (weight) of carbon black and water.
5: 99.5 is suitable, more preferably 50:50.
To 2:98, more preferably 20:80 to 5:95.

The oxidizing agent is not particularly limited as long as it increases the acidic functional group in the carbon black. In general, it is preferable that the oxidizing agent does not remain in water after the oxidizing agent is oxidized. It is preferably used. Specifically, carbon black can be oxidized through ozone and / or an ozone-containing gas. Here, the oxidant, ozone, can be generated by an ozone generator. This ozone generator generally generates ozone by discharging in air or oxygen, but it can also be generated by electrolyzing water. As the generator for generating ozone used in the present invention, any generator can be used irrespective of the system. However, a higher ozone generation concentration is preferable because the reaction efficiency of oxidation of carbon black is higher. Generally, generators for generating an ozone-containing gas having an ozone concentration of 1 to 20% by weight are commercially available, and these are sufficient.

As described above, carbon black is oxidized by ozone in the presence of water, and the total amount of acidic groups on the surface of the carbon black becomes a specific amount, or the active hydrogen content becomes a specific amount, as described later. By oxidizing to the extent possible, carbon black having particularly good dispersibility in an aqueous medium can be obtained. Most preferably, by oxidizing both the amount of total acidic groups and the content of active hydrogen within the ranges described below, the dispersibility in an aqueous medium becomes extremely good. The mechanism by which such a simple operation provides oxidized carbon black with excellent properties is not clear, but if water is present on the surface of the carbon black, the ozone does not directly react with the surface of the carbon black. It is also conceivable that, by dissolving in water and reacting with water molecules, the resulting functional groups also have good compatibility with water and exhibit dispersion stability. For these reasons, compared to carbon black that has been oxidized by ozone oxidation in the gaseous phase to the extent that it has the same total acid groups, it is still an oxidized carbon black that has greatly improved dispersibility in water. It is presumed to exhibit an unexpected effect of becoming.

The carbon black to be subjected to the above-described oxidation treatment with ozone in the presence of water does not need to be oxidized in advance, but prior to the oxidation in the presence of water, prior to oxidation in the presence of water, nitric acid or a gaseous phase known in the art is used. The carbon black treated with ozone may be oxidized by the above method. By the above-described oxidation treatment with ozone in the presence of water, all the acidic groups of carbon black are reduced to 3 μequ / m ^2.
It is desirable to perform the oxidation treatment until the above is reached. The amount of all acidic groups can be determined as the amount reacted with a strong alkali such as NaOH or KOH.

The method for determining the total acidic groups is as follows. The oxidized carbon black is filtered through a 0.1 micron membrane filter to separate it from water. The separated carbon black is dried all day and night with a dryer at 60 ° C., and then pulverized in an agate mortar. Take 0.2-0.5 g of this dried carbon black,
The flask is placed in an Erlenmeyer flask containing 60 cc of 0.01 N NaOH, and nitrogen is flowed into the Erlenmeyer flask. The mixture is stirred for 6 hours to react. The reaction product is filtered again using a 0.1 micron membrane filter to obtain a filtrate. Take 40 cc of this filtrate and titrate with 0.025 N hydrochloric acid using an automatic neutralization titrator to determine the NaOH concentration of the filtrate.

The total acidic groups of carbon black can be determined by the following calculation.

(Equation 1) If the total acidic group is less than 3 μequ / m ² , dispersion in an aqueous medium may be difficult.

More preferably, if it is at least 6 μequ / m ² , the dispersibility in an aqueous medium will be very good. Also,
Active hydrogen content of 2.0mmo as carbon black
1 / g or less, particularly preferably 1.5 mmol / g or less is suitably used.

It has been surprisingly found that carbon black having an active hydrogen content of not more than a specific amount is particularly excellent in dispersibility in an aqueous medium and can provide an aqueous dispersion of carbon black having excellent dispersion stability. The inventor has found. Conventionally,
For example, as in the method described in JP-A-8-3498, it has been considered that the acid treatment increases the number of acidic functional groups on the surface of carbon black due to the oxidation treatment, which leads to hydrophilicity and simply contributes to stability in an aqueous medium. It seems. On the other hand, the present inventors surprisingly found that the functional group imparted by the oxidation treatment is detected as a total acidic group, but is not necessarily linked to an increase in the functional group detected as the active hydrogen content. Further, carbon black having a high active hydrogen content is not always said to be excellent in dispersion in an aqueous medium, and increasing the active hydrogen content does not lead to improvement in dispersibility, but rather lowers. I found it. And the active hydrogen content is 2.0 mm
It was found that when an aqueous dispersion was prepared using carbon black of ol / g or less, the dispersibility of carbon black in an aqueous medium was particularly excellent.

The active hydrogen content is determined by the following method. The active hydrogen on the carbon black is exchanged for a methyl group by dropping a diethyl ether solution of diazomethane on the carbon black. Hydrogen iodide having a specific gravity of 1 is added to the carbon black thus treated, and heated to vaporize the methyl group as methyl iodide. This gas of methyl iodide is trapped by a silver nitrate solution and precipitated as methyl silver iodide. From the weight of the silver iodide, the amount of the original methyl group, that is, the amount of active hydrogen is measured.

When the carbon black has been subjected to a treatment such as an oxidation treatment and contains a large amount of residual ions, for example, by treatment with sodium hypochlorite, desalting is performed.
An accurate active hydrogen content is obtained by performing a neutralization treatment. As a simple method of performing this desalting, a method of passing a carbon black dispersion through a column containing a cation exchange resin and an anion exchange resin can be used. By such a treatment, the cations associated with the functional groups can be removed, and the pH of the dispersion is acidic, so that the amount of active hydrogen contained in the carbon black can be accurately indicated. In such a pretreatment, the amount of cations in the carbon black is 1000 p.
pm or more. More specifically, a carbon black dispersion (if the carbon black is in a dry state, a dispersion obtained by once dispersing it in water)
After removing the cations through a column packed with a mixture of an anion exchange resin and a cation exchange resin, 0.1 g of the mixture was added.
The mixture is filtered through a 1 μm membrane filter to take out carbon black. 100 ° C
After drying all day and night in a dryer, pulverize in a mortar,
Get a sample. Take 1.0 g of this sample, place it in a flask containing an excess amount of hydrogen iodide solution, heat and boil to generate methyl iodide, transport the generated methyl iodide with nitrogen gas, and use a silver nitrate solution Collect and sediment. After the collected liquid is made acidic with nitric acid, the precipitate is collected by filtration through a membrane filter. After drying the precipitate at 50 ° C., the weight is measured to determine the amount of active hydrogen.

The carbon black is oxidized by ozone in the presence of water, and is oxidized until the active hydrogen content on the surface of the carbon black becomes a specific amount or less, as described later, thereby dispersing the carbon black in an aqueous medium. Excellent carbon black can be obtained. It has been found that when such an oxidation method is employed, the number of functional groups detected as active hydrogen content decreases and the number of acidic functional groups detected as total acidic groups increases, surprisingly. Although the mechanism by which the acidic functional groups contributing to the dispersibility in water are imparted in a well-balanced manner by such a simple oxidation treatment operation to obtain carbon black with excellent properties is not clear, it is presumed as follows.
Carbon black is composed of particles formed by carbonizing raw hydrocarbons while undergoing thermal decomposition and dehydrogenation.
Hydrogen that has not been dehydrogenated remains in the particles as active hydrogen. When this carbon black is oxidized with ozone in the presence of water, radicals are generated by the reaction of ozone and water, and a functional group that is compatible with water is generated by replacing active hydrogen, which is originally unfamiliar with water. It is considered that carbon black having good dispersibility in water can be obtained.

By mixing a polar solvent with the aqueous dispersion thus prepared, an aqueous ink having excellent performance can be obtained. Here, the aqueous carbon black dispersion refers to a dispersion of carbon black in water or a mixture of water and a water-soluble solvent. Specific examples of the polar solvent include lower alcohols such as ethanol and isopropanol, glycol solvents such as glycerin, diethylene glycol and polyethylene glycol, N-containing solvents such as N-methylpyrrolidone and 2-pyrrolidone, and urea. is there.

The concentration of the oxidized carbon black in the aqueous dispersion may be appropriately selected according to the application, but is preferably 0.5 to 50% by weight, particularly preferably 0.5 to 20% by weight. Preferably, it is a black aqueous dispersion. In this range, the printing density of the ink is good, and the viscosity of the ink is suppressed, so that an ink having excellent characteristics can be obtained. The aqueous carbon black dispersion thus obtained can be used as an aqueous ink by adding various additives such as adding a dispersant as needed when the concentration of carbon black exceeds 20 wt%, for example. If necessary, concentrate and dry,
Thereafter, it can be separately diluted and used as an ink. In this case, carbon black may be added to water, and a dispersion treatment using a bead mill, a ball mill, an impact disperser or the like may be used.

Here, in the present invention, the amount of iron in the dispersion is 5 ppm or less. Alternatively, the amount of silicon is set to 5 ppm or less. Alternatively, the total amount of silicon and iron is set to 10 ppm or less. According to the study of the present inventor, that the silicon content affects the ejection stability of the ink, that the iron content affects the ejection stability of the ink, and that the silicon content and the iron content Was found to affect the ejection stability. For each of iron and silicon, those below a certain upper limit have better ink ejection stability than those above that upper limit. In other words, an aqueous carbon black dispersion having an iron content of 5 ppm or less, an aqueous carpon black dispersion having a silicon content of 5 ppm or less, and an aqueous carbon black dispersion having a total iron and silicon content of 10 ppm or less,
Each is excellent in ejection stability.

The iron content can be measured using an atomic absorption spectrophotometer. The silicon content can be measured by the ICP method. When the content of silicon or iron exceeds the range specified in the present invention, the treatment with an ion exchange resin may be carried out to 10 ppm or less. Alternatively, as a means for reducing silicon, a raw material hydrocarbon having a low silicon content is carefully selected as a raw material hydrocarbon when producing carbon black, and pure water may be used as cooling water used to stop the carbon black generation reaction. Further, as a method for reducing iron, a magnetic separation step of carbon black may be appropriately performed. Further, it is preferable to use water and additives having low iron and silicon contents when oxidizing carbon black and when preparing ink. Examples of the additive for forming an ink include a penetrant, a fixing agent, a fungicide, and the like.

As the penetrating agent, a nonionic surfactant such as polyoxyethylene alkylaryl ether, an anionic surfactant such as alkylbenzene sulfonate, a fluorine surfactant, diethylene glycol monobutyl ether, and the like can be used. Can be. As the fixing agent, in addition to water-soluble resins (nonionic water-soluble resins such as polyvinyl alcohol and polyacrylamide, anionic water-soluble resins such as polyacrylic acid and styrene / acrylic water-soluble resins), aqueous emulsions can also be used. .
In general, when used as an inkjet ink, a carbon black concentration of 1 to 20% by weight, preferably 5 to 10% by weight is used. When used as an inkjet ink, it is desirable to adjust the pH to 7 to 10 before use.

The ink of the present invention obtained in this manner is required to be used as an ink for ink-jet printing, and has stability for forming droplets, ejection stability for a long time, ejection stability after a long pause, storage stability, and the like. Both the fixing property to the recording material, the weather resistance of the recorded image, and the like are balanced. Therefore, it is possible to impregnate the ink absorber with the aqueous ink of the present invention, store the ink absorber in an ink tank, and obtain an ink cartridge having the ink tank. Further, since the water-based ink of the present invention does not contain a dispersant, problems in the case of using a dispersant, for example, deterioration of print quality such as reduction in print density and occurrence of bleeding can be suppressed. Therefore, for example, in an ink jet recording ink set for recording a color image on a recording material using at least two inks of a black ink and a color ink, the black ink contains the carbon black of the present invention. Is, and, in the color ink, at least a colorant and a surfactant are included,
And, if the color ink contains at least a colorant and a surfactant, and the polarity of the colorant contained in at least one color ink is opposite to the black ink, This is preferable because bleeding during multicolor printing can be reduced. By using such an ink set, ink droplets can be ejected from an orifice in accordance with a recording signal to perform ink jet recording for recording on a recording material, and ink can be stored using such an ink set. A recording unit including a head unit for discharging the ink as ink droplets, and an ink container containing ink using such an ink set. It is possible to form an ink jet recording apparatus having a recording unit having a head section for discharging ink as an ink cartridge, and to form an ink cartridge having an ink storage section storing such an ink set. Inkjet recording can be performed by using such an ink cartridge. It is possible to form the device for an ink jet recording Te. The formation of the ink set, the formation of the ink cartridge, and the ink jet recording method are described in, for example, JP-A-10-1400.
Known techniques in the art, such as those described in JP-A-63-63 and JP-A-10-140064, can be appropriately employed. Furthermore, for the purpose of color tone adjustment, etc.,
A dye may be added. For example, JP-A-8
-92512, JP-A-2-276872,
JP-A-2-276873, JP-A-2-27687
No. 5, JP-A-3-66768, JP-A-3-3-1
40377, JP-A-4-57859-57865
A known method, such as that described in Japanese Patent Application Laid-Open Publication No. H10-209, may be employed.

[0028]

Example 1 70 g of Mitsubishi Chemical carbon black # 960 was placed in 1000 cc of ion-exchanged water and dispersed with a household mixer for 5 minutes. The obtained liquid was placed in a 3 liter stainless steel container containing 1 liter of zirconia beads having a diameter of 1 mm. An ozone-containing gas having an ozone concentration of 10% by weight was introduced at a rate of 3 L / min for 5 hours. In addition, a stirrer equipped with three 100 mm-diameter disks having a rotating machine was placed in the container, and the dispersion was performed simultaneously. At this time, ozone was generated using an ozonizer manufactured by PCI Corporation in the United States as an ozone generator. The dispersion after the ozone treatment was taken out and the pH was measured. (The pH was measured according to JIS K 6221.) These liquids were taken, and confirmed under an optical microscope at a magnification of 400 times. I understand.

Next, the carbon black was filtered from the dispersion with a micropore filter having a diameter of 0.1 μm, and the wet carbon black was dried at 60 ° C. to measure the total acidic groups. Total acidic groups per unit area were determined. The active hydrogen content of carbon black was also measured. The amount of iron and silica in this dispersion is 1 ppm each.
It was below. Dispersion 100 obtained by the above oxidation treatment
0 cc was placed in a beaker, 200 cc of an anion exchange resin (“SAN UP” manufactured by Mitsubishi Chemical Corporation) was placed in the beaker, heated to 50 ° C., and stirred with a stirrer for 3 hours. Then, it was cooled to room temperature,
Centrifugal sedimentation was performed for 30 minutes at rpm to remove ion exchange resin and other foreign substances. 0.1N N was added to the supernatant.
The pH was adjusted to 8 by adding the aOH solution little by little.

The total acidic groups of this carbon black are 3.8
μequ / m ² and the amount of active hydrogen were 1.7 mmol / g. 10 cc of isopropyl alcohol and 5 cc of methylethanolamine are added to 100 cc of these prepared solutions.
cc, packed in NEC cartridges NEC
When printing was performed using a printer “PR101” manufactured by Co., Ltd., the printed matter was good with no blurring of 100 sheets or more.

Example 2 To the carbon black dispersion obtained in Example 1, iron chloride was added so as to be 5 ppm as iron, and water glass was added so as to be 4 ppm as silicon, and printing was performed in the same manner as in Example. As a result, as in Example 1, printing was performed without blurring 100 or more sheets.

Comparative Example 1 A treatment was carried out using steel beads instead of the zirconia beads of Example 1. Further, the same processing was performed except that the ion exchange processing performed in Example 1 was not performed. The concentration of iron in this dispersion was 21 ppm. When this dispersion was printed in the same manner as in the example, 50
From the first sheet, white spots became visible.

Comparative Example 2 Carbon black produced by cooling with industrial water was used in place of # 960 in Example 1, and instead of ion-exchanged water,
The treatment was performed using general industrial water. The silicon content in this carbon black was 30 ppm, and the silicon content in industrial water was 11 ppm. Further, the same processing was performed except that the ion exchange processing performed in Example 1 was not performed. The concentration of silicon in this dispersion was 13 pp
m. When printing was performed on this dispersion in the same manner as in the example, white spots became visible from the 70th sheet.

[0034]

According to the present invention, there is no clogging or sediment generation in the orifice of the nozzle or at the tip thereof especially when used for ink jet or writing ink, and even after being left at a high temperature for a long time, An aqueous dispersion and an aqueous ink that provide stable ejection stability of the ink can be obtained.

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Claims (12)

[Claims] 1. An aqueous carbon black dispersion having an iron content of 5 ppm or less. 2. An aqueous carbon black dispersion having a silicon content of 5 ppm or less. 3. A carbon black aqueous dispersion having a total content of iron and silicon of 10 ppm or less. 4. The method according to claim 1, wherein all the acidic groups of the carbon black are 3 μequ.
Carbon black aqueous dispersion according to claim 1 is / m ² or more. 5. The carbon black having an active hydrogen content of 2.
The aqueous carbon black dispersion according to any one of claims 1 to 4, wherein the amount is 0 mmol / g or less. 6. The aqueous carbon black dispersion according to claim 1, wherein the carbon black has been oxidized in the presence of water. 7. The aqueous carbon black dispersion according to claim 6, wherein the oxidation treatment is performed using ozone. 8. The aqueous carbon black dispersion according to claim 1, which has a pH of 5 to 10. 9. A carbon black having a particle size of 10 to 30 n.
The aqueous dispersion according to any one of claims 1 to 8, wherein m and the DBP oil absorption are 50 to 180 cc / 100 g. 10. A carbon black content of 0.5 to 5
The aqueous carbon black dispersion according to any one of claims 1 to 9, wherein the amount is 0% by weight. 11. An aqueous ink using the aqueous carbon black dispersion according to claim 1. 12. The ink according to claim 1, which is an ink for ink jet.
2. The aqueous ink according to 1.