JP2008163132A - Aqueous carbon black dispersion, method for producing the same, and aqueous ink - Google Patents

Abstract

A water-based carbon having a low viscosity, a high printing density of printed matter on plain paper, excellent marker resistance, excellent storage stability, excellent ejection stability, and excellent properties as an inkjet ink. A black dispersion, a method for producing the same, and a water-based ink are provided.
(A) a (co) polymer having a structural unit derived from a diene monomer and having a sulfonic acid group or a salt thereof and / or a hydrogenated product thereof; and (B-1) a DBP absorption amount. An aqueous carbon black dispersion containing carbon black of 250 ml / 100 g or more and (B-2) carbon black having a DBP absorption of less than 250 ml / 100 g.
[Selection figure] None

Description

  The present invention relates to a water-based carbon black dispersion suitable for a water-based ink, particularly a water-based ink useful as an ink for ink jet recording, a method for producing the same, and a water-based ink.

  2. Description of the Related Art A method of recording on a substrate such as paper by an ink jet method has been adopted in printers such as computers and has been rapidly spreading in recent years. Inkjet recording is a method of recording images, characters, etc. by ejecting fine ink droplets and depositing them on a recording sheet such as paper or a polymer sheet. It is high speed, low noise, and multicolored. It is possible, has a feature that the recording pattern has great flexibility and development-fixing is unnecessary.

  Conventional inks for ink jet recording have used dye inks in which various dyes are dissolved in water or a mixed solvent of water and an organic solvent. However, dye inks have drawbacks such as a large amount of bleeding and poor print quality and water resistance. In view of this, there has been proposed an ink that has less blurring, excellent print quality, and excellent water resistance (see, for example, Patent Document 1). In recent years, pigment inks that have less blurring, excellent print quality, light resistance, and water resistance have been studied. In the above Patent Document 1, the use of a pigment is also proposed. However, when a pigment is used, the dispersibility of pigment particles in the ink, the dispersion stability, clogging at the print head, ejection stability, etc. However, this was not always sufficient. In particular, with the progress of high definition ink jet printers in recent years, conventional pigment inks are likely to be clogged with a print head and the print quality is insufficient.

  Accordingly, various studies have been made on the dispersibility of pigment particles in ink (see, for example, Patent Documents 2 and 3). Among these, for example, there is a proposal to make the pigment fine, but even if the pigment can be made fine, simply making it fine increases the viscosity of the pigment ink, or once settled pigment Since the dispersion stability of the ink was poor, redispersion was difficult, and the printing density and marker resistance were not sufficient.

  In addition, when carbon black is used as a pigment, an ink containing an aqueous dispersion of water-insoluble vinyl polymer particles containing carbon black has been proposed in order to improve the dispersion stability of carbon black and increase the printing density. (For example, see Patent Document 4). However, the ink viscosity or the printing density when printed on plain paper is not yet sufficient, and further, there is a problem that the storage stability of ink or the marker resistance when printed on plain paper is not sufficient.

Japanese Patent Laid-Open No. 11-217525 JP 07-238234 A JP 09-272832 A Japanese Patent Laid-Open No. 2005-42098

  The present invention has been made against the background of the above-mentioned conventional technical problems, and has a low viscosity, a high print density of printed matter on plain paper, excellent marker resistance, excellent storage stability, and excellent discharge stability. An object of the present invention is to provide a water-based carbon black dispersion that is excellent and exhibits excellent properties as an ink-jet ink, a method for producing the same, and a water-based ink.

  As a result of intensive studies to achieve the above object, the present inventors solved the above problems by using a specific polymer, two specific types of carbon black, and a specific acetylene alcohol as described below. The present inventors have found that this can be done and have completed the present invention. That is, according to the present invention, the following aqueous carbon black dispersion, a method for producing the same, and an aqueous ink are provided.

[1] (A) a (co) polymer containing a structural unit derived from a diene monomer or a hydrogenated product of a (co) polymer containing a structural unit derived from a diene monomer, and A polymer having a sulfonic acid group or a salt thereof, (B-1) carbon black having a DBP absorption of 250 ml / 100 g or more, (B-2) carbon black having a DBP absorption of less than 250 ml / 100 g, (C) water, And (D) an aqueous carbon black dispersion containing an acetylene alcohol represented by the following general formula (1).

（Ｒ^１及びＲ^２は、水素又は炭素数１〜１０のアルキル基である。Ｒ^１とＲ^２とは、同一であってもよいし異なっていてもよい）

(R ¹ and R ² are hydrogen or an alkyl group having 1 to 10 carbon atoms. R ¹ and R ² may be the same or different.)

[2] Carbon black having (B-1) DBP absorption of 250 ml / 100 g to 500 ml / 100 g, and (B-2) Carbon black having DBP absorption of 130 ml / 100 g to 230 ml / 100 g. The aqueous carbon black dispersion according to [1].

[3] Mass ratio of said (B-1) component and said (B-2) component is (B-1) / (B-2) = 5 / 95-40 / 60 [1]-[ 2] The aqueous carbon black dispersion according to any one of [2].

[4] The aqueous carbon black dispersion according to any one of [1] to [3], wherein the number average particle diameter of the carbon black ((B-1) and (B-2)) contained is 50 to 250 nm. liquid.

[5] (A) a (co) polymer containing a structural unit derived from a diene monomer or a hydrogenated product of a (co) polymer containing a structural unit derived from a diene monomer, and A polymer having a sulfonic acid group or a salt thereof, (B-1) carbon black having a DBP absorption of 250 ml / 100 g or more, (B-2) carbon black having a DBP absorption of less than 250 ml / 100 g, (C) water And (D) A method for producing an aqueous carbon black dispersion that is dispersed in the presence of acetylene alcohol.

[6] An aqueous ink containing the aqueous carbon black dispersion according to any one of [1] to [4].

[7] The water-based ink according to [6], which is used as an ink for inkjet recording.

  The aqueous carbon black dispersion of the present invention has a low viscosity, a high print density of printed matter on plain paper, excellent marker resistance, excellent storage stability, and excellent discharge stability. can get. Furthermore, the printing characteristics of printing on plain paper using the above water-based ink are excellent, and it is suitable as an ink for ink jet recording. In addition, the aqueous carbon black dispersion of the present invention can be efficiently produced by the method for producing an aqueous carbon black dispersion of the present invention.

  Hereinafter, embodiments of the water-based carbon black dispersion, the production method thereof, and the water-based ink of the present invention will be specifically described.

  The aqueous carbon black dispersion of the present invention is (A) (co) polymer containing a structural unit derived from a diene monomer or (co) polymer water containing a structural unit derived from a diene monomer. An additive and a polymer having a sulfonic acid group or a salt thereof (component (A)), (B-1) carbon black having a DBP absorption of 250 ml / 100 g or more (component (B-1)), ( B-2) contains carbon black (component (B-2)) having a DBP absorption of less than 250 ml / 100 g, (C) water, and (D) an acetylene alcohol represented by the following general formula (1) Is.

In the general formula (1), R ¹ and R ² are hydrogen or an alkyl group having 1 to 10 carbon atoms. R ¹ and R ² may be the same or different.

  Hereinafter, each component will be described in detail.

(A) component:
Component (A) used in the present invention (a (co) polymer containing a structural unit derived from a diene monomer or a hydrogenated (co) polymer containing a structural unit derived from a diene monomer) And a polymer having a sulfonic acid group or a salt thereof) is a diene-based (co) polymer having a diene monomer as an essential component or a hydrogenated product thereof (hereinafter also referred to as “base polymer”). Is obtained by sulfonation. The component (A) is used as a carbon black dispersant in an aqueous carbon black dispersion or an aqueous ink using the same. By using the component (A), an aqueous carbon black dispersion excellent in storage stability and marker resistance and an aqueous ink using the aqueous carbon black dispersion can be obtained.

  The diene monomer used in the base polymer is preferably a diene monomer having 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms, still more preferably a diene monomer having 4 to 6 carbon atoms. Is the body. Specific examples of the diene monomer include 1,3-butadiene, 1,2-butadiene, 1,2-pentadiene, 1,3-pentadiene, 2,3-pentadiene, isoprene, and 1,2-hexadiene. 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,3-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3 -Butadiene, 1,2-heptadiene, 1,3-heptadiene, 1,4-heptadiene, 1,5-heptadiene, 1,6-heptadiene, 2,3-heptadiene, 2,5-heptadiene, 3,4-heptadiene In addition to 3,5-heptadiene, etc., various aliphatic or alicyclic dienes having 4 to 7 carbon atoms may be mentioned. One kind alone or two or more kinds may be used in combination. It can be used. Particularly preferred are 1,3-butadiene and isoprene.

  In addition to these diene monomers, other monomers can be used in combination. Examples of other monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, methyl (meth) acrylate, (Meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl ester such as butyl (meth) acrylate, (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and other mono- or dicarboxylic acid or dicarboxylic acid Examples thereof include unsaturated compounds such as anhydrides, vinylcyan compounds such as (meth) acrylonitrile, vinyl chloride, vinylidene chloride, vinyl methyl ethyl ketone, vinyl acetate, (meth) acrylamide, and glycidyl (meth) acrylate. These other monomers can be used alone or in combination of two or more. Of these other monomers, styrene is preferred.

  When these other monomers are used in combination, the amount of diene monomer used is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 5% by mass or more. If it is less than 0.5% by mass, the sulfonic acid (salt) group content introduced into the sulfonated product obtained by sulfonation may be low, which is not preferable.

  The base polymer is composed of diene monomer and other monomers as required, radical polymerization initiator such as hydrogen peroxide, benzoyl peroxide, azobisisobutyronitrile, or n-butyllithium, sodium naphthalene. In the presence of an anionic polymerization initiator such as sodium metal, it is obtained by (co) polymerization at −100 to 150 ° C., preferably 0 to 130 ° C., using a known solvent as necessary. It is done.

  The base polymer also includes a hydrogenated product of part or all of the double bond based on the diene monomer of the (co) polymer. In this case, the (co) polymer can be obtained by a known hydrogenation catalyst, for example, a catalyst and method described in JP-A-5-222115.

  The base polymer used in the present invention is a homopolymer or a copolymer, and the copolymer may be a random type or a block type copolymer such as AB type or ABA type without particular limitation. Preferred base polymers include, for example, isoprene homopolymer, butadiene homopolymer, isoprene-styrene random copolymer, isoprene-styrene block copolymer, styrene-isoprene-styrene ternary block copolymer, butadiene-styrene. Random copolymer, butadiene-styrene block copolymer, styrene-butadiene-styrene block copolymer, butadiene-styrene-butadiene ternary block copolymer, isoprene-styrene-isoprene-styrene-isoprene ternary block copolymer , Butadiene-styrene-butadiene-styrene-butadiene quaternary block copolymers, (co) polymers partially or fully hydrogenated (co) polymers with residual double bonds of these (co) polymers, etc. Is mentioned. Of these, more preferred are isoprene-styrene block copolymers, styrene-isoprene-styrene ternary block copolymers, butadiene-styrene block copolymers, styrene-butadiene-styrene block copolymers, butadiene-styrene. A butadiene ternary block copolymer, an isoprene-styrene-isoprene-styrene-isoprene quinary block copolymer, and hydrogenated products thereof.

  The weight average molecular weight (hereinafter referred to as “Mw”) of the base polymer in terms of polystyrene is preferably 1,000 to 500,000, more preferably 3,000 to 100,000, and particularly preferably 5,000 to 20,000. It is. If the Mw is less than 1,000, sufficient dispersibility of the carbon black cannot be obtained. On the other hand, if it exceeds 500,000, the dispersibility of the carbon black decreases or the viscosity of the carbon black dispersion increases. Sometimes.

  As the component (A), the above base polymer is sulfonated by a known method such as the method described in the Chemical Society of Japan, New Experimental Course (Vol. 14, III, page 1773) or JP-A-2-227403. To obtain. That is, in the base polymer, the double bond portion of the diene unit in the polymer can be sulfonated using a sulfonating agent. During this sulfonation, the double bond becomes a single bond, or the hydrogen atom replaces the sulfonic acid while the double bond remains. In addition, when another monomer, for example, an aromatic vinyl monomer, is used, the aromatic unit may be sulfonated in addition to the diene unit portion of the double bond portion. In this case, the sulfonating agent is preferably sulfuric anhydride, a complex of sulfuric anhydride and an electron donating compound, sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, bisulfite (Na salt, K salt, Li salt, etc.) Etc. are used.

  Here, as the electron-donating compound, ethers such as N, N-dimethylformamide, dioxane, dibutyl ether, tetrahydrofuran and diethyl ether; amines such as pyridine, piperazine, trimethylamine, triethylamine and tributylamine; dimethyl sulfide, diethyl Sulfides such as sulfide; nitrile compounds such as acetonitrile, ethyl nitrile, propyl nitrile, and the like, and among them, N, N-dimethylformamide and dioxane are preferable.

  The amount of the sulfonating agent is usually 0.005 to 1.5 mol in terms of sulfuric anhydride, preferably 1 mol in total for the diene monomer unit and the aromatic vinyl monomer unit in the base polymer. Is from 0.01 to 1.0 mol, and if it is less than 0.005 mol, the desired sulfonation rate cannot be obtained, so that various performances cannot be expressed, whereas if it exceeds 1.5 mol, The amount of unreacted sulfuric anhydride increases, and after neutralization with alkali, a large amount of sulfate is produced, and the purity is lowered.

  In the sulfonation, a solvent inert to the sulfonating agent such as sulfuric anhydride can be used. Examples of the solvent include halogenated hydrocarbons such as chloroform, dichloroethane, tetrachloroethane, tetrachloroethylene, and dichloromethane; nitromethane And nitro compounds such as nitrobenzene; aliphatic hydrocarbons such as liquid sulfur dioxide, propane, butane, pentane, hexane and cyclohexane, and ether solvents such as dioxane and tetrahydrofuran. These solvents can be used as a mixture of two or more. The sulfonation reaction temperature is usually −70 to 200 ° C., preferably −30 to 50 ° C. If the temperature is lower than −70 ° C., the sulfonation reaction is slow and is not economical. May cause the product to blacken or become insoluble.

  The component (A) can be obtained by allowing water or a basic compound to act on this product. By allowing water to act after sulfonation, a sulfonic acid group is produced, and by reacting a basic compound, a salt of the sulfonic acid group is produced. Examples of the basic compound include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; sodium methoxide, sodium ethoxide, potassium methoxide, sodium-t-butoxide, potassium-t-butoxide, and the like. Alkali metal alkoxides; carbonates such as sodium carbonate, potassium carbonate, lithium carbonate; methyl lithium, ethyl lithium, n-butyl lithium, sec-butyl lithium, amyl lithium, propyl sodium, methyl magnesium chloride, ethyl magnesium bromide, propyl magnesium Organometallic compounds such as iodide, diethylmagnesium, diethylzinc, triethylaluminum, triisobutylaluminum; ammonia water, trimethylamine, triethylamino , Amines such as tripropylamine, tributylamine, pyridine, aniline, dimethylethanolamine, dietanolamine, triethanolamine, monoethanolamine, aminomethylpropanol, piperazine; sodium, lithium, potassium, calcium, zinc And metal compounds such as These basic compounds can be used alone or in combination of two or more. Among these basic compounds, alkali metal hydroxides and amines are preferable, and sodium hydroxide and lithium hydroxide are particularly preferable.

  The usage-amount of a basic compound is 2 mol or less with respect to 1 mol of used sulfonating agents, Preferably it is 1.3 mol or less. In this reaction, the basic compound can be used in the form of an aqueous solution, or can be used by dissolving in an organic solvent inert to the basic compound. Examples of the organic solvent include various organic solvents used for the sulfonation, aromatic hydrocarbon compounds such as benzene, toluene, and xylene; alcohols such as methanol, ethanol, propanol, isopropanol, and ethylene glycol. It is done. These solvents can be used as a mixture of two or more.

  When the basic compound is used as an aqueous solution or an organic solvent solution, the concentration of the basic compound is usually 1 to 70% by mass, preferably about 10 to 50% by mass. Moreover, this reaction temperature is normally -30-150 degreeC, Preferably it is 0-120 degreeC, More preferably, it is carried out at 50-100 degreeC, and it can implement any of a normal pressure, pressure reduction, or pressurization. Furthermore, reaction time is 0.1 to 24 hours normally, Preferably it is 0.5 to 5 hours.

  The sulfonic acid (salt) group content of the component (A) synthesized as described above is 0.1 to 3.5 mmol / g, preferably 0.2 to 3 mmol / g. If it is less than 0.1 mmol / g, the dispersibility of the carbon black is lowered as will be described later. On the other hand, if it exceeds 3.5 mmol / g, the water resistance of the printed matter is lowered, which is not preferred. The content of the sulfonic acid (salt) group in the component (A) can be confirmed from the absorption of the sulfonic acid group by infrared absorption spectrum, and the composition ratio thereof can be known by elemental analysis or the like. Moreover, the structure can be confirmed by a nuclear magnetic resonance spectrum.

  The component (A) synthesized in this manner is preferably a component emulsified in water (hereinafter also referred to as “re-emulsified product”). The method of re-emulsification is the above-mentioned component (A) or the organic solvent solution of the product before neutralization is stirred and mixed with water or the alkali compound and emulsified, and then the organic solvent is removed while leaving water. Can be obtained. This re-emulsification can adopt a general method, a method of adding water to the organic solvent solution of the component (A) while stirring, a method of adding the organic solvent solution of the component (A) to water while stirring. There are no particular restrictions on the method of adding and stirring the organic solvent solution of component (A) and water simultaneously.

  Here, examples of the organic solvent used for re-emulsification include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane and heptane, ketone solvents such as acetone and methyl ethyl ketone, and ethers such as tetrahydrofuran and dioxane. Solvents such as ester solvents such as ethyl acetate and butyl acetate, and alcohol solvents such as methanol, ethanol and isopropyl alcohol are used. These solvents may be used alone or in combination of two or more.

  The amount of the organic solvent used in the re-emulsification is preferably 20 to 5,000 parts by mass, more preferably 50 to 2,000 parts by mass with respect to 100 parts by mass of the component (A). If the amount is less than 20 parts by mass, a stable re-emulsified product cannot be obtained. On the other hand, if the amount exceeds 5,000 parts by mass, productivity deteriorates. Moreover, the amount of water used in the re-emulsification is preferably 50 to 10,000 parts by mass, more preferably 100 to 5,000 parts by mass with respect to 100 parts by mass of the component (A). If it is less than 50 parts by mass, it is difficult to obtain a stable re-emulsified product. On the other hand, if it exceeds 10,000 parts by mass, the productivity will deteriorate.

  In the re-emulsification, a surfactant can be used in combination. As this surfactant, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxysorbitan ester, polyoxyethylene alkylamine ether, oleate, laurate, rosinate, dodecylbenzenesulfonate And anionic surfactants such as polyoxyethylene alkyl ether sulfates, and cationic surfactants such as octyltrimethylammonium bromide, dioctyldimethylammonium chloride, and dodecylpyridinium chloride. These surfactants can be used alone or in combination of two or more. The surfactant may be used by being dissolved or dispersed in a solution of the organic solvent as the component (A), or may be used by dissolving or dispersing in water. The usage-amount of the said surfactant is 10 mass parts or less normally with respect to 100 mass parts of (A) component, Preferably it is 5 mass parts or less. If it exceeds 10 parts by mass, the purity of the sulfonated emulsion (re-emulsified product) is lowered.

  In order to adjust the pH of the system, alkali compounds such as sodium hydroxide and lithium hydroxide, amines, inorganic acids such as hydrochloric acid and sulfuric acid can also be added. A preferred pH is 5-12. Moreover, if it is a small quantity, organic solvents other than water can also be used together.

  The concentration of the component (A) in the aqueous carbon black dispersion according to the present invention is preferably 1 to 20% by mass, and more preferably 5 to 15% by mass. When the concentration of the component (A) is less than 1% by mass, sufficient dispersibility of the carbon black cannot be obtained, and when the concentration exceeds 20% by mass, the viscosity of the aqueous carbon black dispersion increases, and the carbon black may not be obtained. It cannot be dispersed sufficiently and is not preferable.

(B-1) component, (B-2) component:
The aqueous carbon black dispersion of the present invention includes (B-1) component (carbon black having a DBP absorption of 250 ml / 100 g or more) and (B-2) component (carbon black having a DBP absorption of less than 250 ml / 100 g). ) And are contained. The component (B-1) can increase the printing density when the obtained water-based ink is used as a printed matter. However, the viscosity, storage stability (redispersibility) and marker resistance of the water-based ink can be increased. It was something to lower. On the other hand, the component (B-2) can reduce the viscosity of the obtained water-based ink and improve the storage stability and marker resistance, but printing when the water-based ink is used as a printed matter. The concentration could not be increased. In addition, in the above, DBP absorption amount means the dibutyl phthalate capacity | capacitance adsorb | sucked by carbon black, and is measured according to JISK6221.

  Therefore, in order to make use of the above-mentioned advantages of the component (B-1) and the component (B-2) and to compensate for the disadvantages, the aqueous carbon black dispersion of the present invention is used in combination. As a result, the viscosity of the obtained water-based ink can be reduced, storage stability and marker resistance can be improved, and furthermore, the print density can be increased when the water-based ink is used as a printed matter.

The component (B-1) has a DBP absorption amount of 250 ml / 100 g or more, preferably 250 to 500 ml / 100 g, and more preferably 300 to 400 ml / 100 g. If it is less than 250 ml / 100 g, the print density cannot be increased when the obtained aqueous ink is used as a printed matter. Further, (B-1) component is preferably a specific surface area of 300~2000m ² / g, and further preferably from 500 to 1500 ² / g. When the specific surface area is less than 300 m ² / g, the print density is not increased, and when it exceeds 2000 m ² / g, the viscosity of the slurry and the ink is unfavorably increased.

Component (B-2) has a DBP absorption of less than 250 ml / 100 g, preferably 130 to 230 ml / 100 g, and more preferably 150 to 230 ml / 100 g. When it is 250 ml / 100 g or more, the viscosity of the obtained water-based ink is lowered, and the storage stability and the marker resistance cannot be improved. The component (B-2) preferably has a specific surface area of 200 to 600 m ² / g, and more preferably 230 to 350 m ² / g. When the specific surface area is less than 200 m ² / g, the print density does not increase, and when it exceeds 600 m ² / g, the viscosity of the slurry and ink increases, which is not preferable.

  The mass ratio of the component (B-1) and the component (B-2) contained in the aqueous carbon black dispersion of the present invention is (B-1) / (B-2) = 5/95 to 40/60. It is preferable that the ratio is 10/90 to 30/70. By setting the mass ratio of the component (B-1) to the component (B-2) in such a range, the characteristics of the component (B-1) and the component (B-2) can be expressed in a balanced manner. It becomes possible.

  It is preferable that the number average particle diameter of all the carbon blacks including the component (B-1) and the component (B-2) contained in the aqueous carbon black dispersion of the present invention is 50 to 250 nm. More preferably, it is 100 to 200 nm. If it is smaller than 50 nm, the printing density does not increase, and if it exceeds 250 nm, the storage stability becomes poor.

  The carbon black (the sum of the (B-1) component and the (B-2) component) contained in the aqueous carbon black dispersion of the present invention is preferably 2 to 30% by mass, and 5 to 20% by mass. More preferably. If the concentration of carbon black is less than 2% by mass, productivity is lowered, which is not preferable. If it exceeds 30% by mass, the viscosity increases, and the pigment cannot be sufficiently dispersed.

  Specific examples of the carbon black (components (B-1) and (B-2)) are as follows.

  (B-1): Printex XE2B (Degussa), Blackpearls 2000 (Cabot), Ketjen Black EC, Ketjen Black EC-300J, Ketjen Black EC-600JD (above, Ketjen Black International) )

  (B-2): Raven 7000, Rayvan 5750, Rayvan 5250, Rayvan 5000 ULTRA, Rayvan 3500, Rayvan 2000, Rayvan 1500, Rayvan 1250, Rayvan 1200, Rayvan 1190ULTRA-II, Rayvan 1170, Rayvan 1255 (and above, Colombia) ), BlackpearlsL, Regal 400R, Regal 330R, Legal 660R, Moguul L, Monarch 700, Monak 800, Monak 880, Monak 900, Monak 1000, Monak 1100, Monak 1300, Monak 1400 , Vulcan XC-72 (above, manufactured by Cabot Corporation), Color Black (Color Bl) ck) FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U , Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (above, manufactured by Degussa), No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, no. 3030, no. 3050, no. 3230, no. 3350, MCF-88, MA600, MA7, MA8, MA100 (above, manufactured by Mitsubishi Chemical Corporation)

(D) component:
The aqueous carbon black dispersion of the present invention contains acetylene glycol (component (D)) represented by the general formula (1). The water-based carbon black dispersion liquid of the present invention contains the component (D), so that when it is used as a water-based (water-based) ink, printing is performed on a recording medium that is rough and easily penetrates liquid such as plain paper. The ink can be prevented from penetrating into the recording medium. Therefore, the print density of the printed matter can be increased. Further, by containing the component (D), the viscosity of the water-based ink can be lowered and the ejection stability can be improved. Examples of the component (D) include 3-methyl-1-pentyn-3-ol, 3-methyl-1-hexyn-3-ol, 3-methyl-1-butyn-3-ol, and 3-methyl-1. -Heptin-3-ol, 3,5-dimethyl-1-hexyn-3-ol, etc. can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, 3-methyl-1-pentyn-3-ol and 3,5-dimethyl-1-hexyn-3-ol are preferable from the viewpoint of printing density.

(E) Water-soluble organic solvent:
The aqueous carbon black dispersion of the present invention may further contain (E) a water-soluble organic solvent (component (E)). Examples of the component (E) include alcohol compounds such as methanol, ethanol, n-propanol, isopropanol, and glycerin; ketone compounds such as acetone, methyl ethyl ketone, methyl isopropyl ketone, and methyl-n-propyl ketone; isopropyl acetate, n-acetate Ester compounds such as propyl and ethyl acetate; glycol compounds such as ethylene glycol, propylene glycol and diethylene glycol; glycol ether compounds such as diethylene glycol monobutyl ether and triethylene glycol monobutyl ether; and N-methyl-2-pyrrolidone and triethanolamine. Nitrogen compounds; other tetrahydrofuran, dioxane, propylene carbonate, dimethyl sulfoxide, dimethylformamide, acetate, etc. Thiodiglycol, although it is generally used include a water-soluble organic solvent thiols like, preferably an alcohol compound, or glycol ether compounds. More preferably, it is an alcohol compound of the following 1) or 2) or a glycol ether compound of the following 3). In addition, the alkyl group of the following 1) and the alkyl group and alkylene group of the following 2) may be linear or branched.

1) A monoalcohol compound having an alkyl group having 3 to 6 carbon atoms.
2) A polyhydric alcohol compound having an alkyl group having 3 to 6 carbon atoms or an alkylene group having 3 to 6 carbon atoms.
3) A glycol ether compound of the above alcohol.

  1) Examples of the monoalcohol compound having an alkyl group having 3 to 6 carbon atoms include n-propanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, pentanol, hexanol and the like.

  2) Examples of polyhydric alcohol compounds having an alkyl group having 3 to 6 carbon atoms or an alkylene group having 3 to 6 carbon atoms include 1,2-pentanediol, 2,5-hexanediol, 1,5-pentanediol, , 2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol, 1,2-butanediol, 1,4-butanediol, 1,3-butanediol, 2,4-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, trimethylolpropane, 1,2,6-hexanetriol 1,2,5-pentanetriol, 3-methyl-1,5-pentanediol, Examples include 3-hexene-2,5-diol.

  3) The glycol ether compound of the alcohol is a glycol ether of the alcohol, and the glycol is mono, di, tri or tetraethylene glycol or mono, di, tri or tetrapropylene glycol, for example, ethylene glycol monohexyl ether. , Diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, tetraethylene glycol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, tetraethylene glycol monohexyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, Triethylene glycol monoisobutyl ether, Raethylene glycol monoisobutyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, triethylene glycol monopropyl ether, tetraethylene glycol monopropyl ether, propylene glycol monohexyl ether, dipropylene glycol monohexyl ether, tripropylene glycol monohexyl Ether, tetrapropylene glycol, tripropylene glycol monobutyl ether, dipropylene glycol monobutyl ether, propylene glycol monobutyl ether, tetrapropylene glycol monohexyl ether, propylene glycol monoisobutyl ether, dipropylene glycol monoisobutyl ether, tripropylene glycol Bruno isobutyl ether, tetrapropylene glycol monoisobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monopropyl ether, tetrapropylene glycol monopropyl ether, and the like.

  Among these, particularly preferred component (E) is 1,2-hexanediol and triethylene glycol monobutyl ether. These alcohol compounds can be used alone or in combination of two or more.

  The component (E) contained in the aqueous carbon black dispersion of the present invention is preferably 200 parts by mass or less and more preferably 100 parts by mass or less with respect to 100 parts by mass of the component (A). When the component (E) exceeds 200 parts by mass, the viscosity of the aqueous carbon black dispersion increases, and the dispersion of carbon black may not be good.

  The content ratio of the component (A), the component (B-1), the component (B-2), the component (C), and the component (D) in the aqueous carbon black dispersion of the present invention is 100 parts by mass in total. In this case, the component (A) is 3 to 15 parts by mass, the component (B-1) is 1 to 5 parts by mass, the component (B-2) is 8 to 20 parts by mass, the component (C) is 50 to 87 parts by mass, And (D) component is preferably 1 to 10 parts by mass, (A) component is 2 to 14 parts by mass, (B-1) component is 2 to 4 parts by mass, and (B-2) component is 10 to 18 parts by mass. The component (C) is more preferably 56 to 84 parts by mass, and the component (D) is more preferably 2 to 8 parts by mass.

Other dispersants:
The aqueous carbon black dispersion of the present invention can further contain other dispersants. Other dispersants include polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer Polymer, styrene-methacrylic acid copolymer, styrene-acrylic acid-alkyl acrylate copolymer, styrene-methacrylic acid-alkyl acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene -Α-methylstyrene-acrylic acid-alkyl acrylate ester copolymer, styrene-maleic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer Coalesced vinyl acetate-maleic acid ester copolymer, Examples thereof include vinyl acetate-crotonic acid copolymer and vinyl acetate-acrylic acid copolymer. The aqueous carbon black dispersion of the present invention may further contain the surfactant, pH adjuster and the like.

Aqueous carbon black dispersion:
The aqueous carbon black dispersion of the present invention comprises (C) an aqueous medium containing water, and the above component (A), component (B-1), component (B-2) and component (D) are mixed with a disperser. Although it is preferable that it was manufactured by dispersion treatment, it may be produced by dispersion treatment in the presence of component (E). The aqueous carbon black dispersion of the present invention is obtained by dispersing the above components (A), (B-1) and (B-2) with a disperser in an aqueous medium containing (C) water. It is also preferable that the carbon black dispersion be prepared and the carbon black dispersion obtained is blended with the component (D). Thus, by carrying out the dispersion treatment in the presence of the component (A), an aqueous carbon black dispersion in which the component (A) functions as a dispersant and carbon black is uniformly dispersed can be obtained. Moreover, you may disperse | distribute in presence of another additive. Water is preferred as the aqueous medium. In the present invention, “dispersing” means to uniformly disperse the predetermined liquid mixture using a disperser. Therefore, simply “stirring with a normal stirrer or the like does not mean“ dispersion treatment ”. Dispersing machines used are sand mills, homogenizers, attritors, ball mills, paint shakers, fluidizers, high speed mixers, ultrasonic dispersing machines, etc. Good or not. The dispersion time is 5 minutes to 24 hours, preferably 30 minutes to 8 hours. More specifically, there is a method of dispersing ink with a planetary ball mill or a sand mill using ceramic beads having a particle diameter of 0.01 to 1.0 mm. In this case, it is preferable to perform the acceleration at a peripheral speed of 5 to 20 m / s at an acceleration of 5 to 50 G for a planetary ball mill and a filling rate of ceramic beads of 50 to 90% for a sand mill. Also, a dispersion prepared in the same manner as the component (B-1) carbon black alone (without the component (B-2)), and the component (B-2) carbon black alone ((B -1) A dispersion prepared in the same manner without adding any component may be mixed.

  The viscosity of the aqueous carbon black dispersion of the present invention is 2 to 20 mPa · s, although it depends on the concentrations of the component (A), the component (B-1), the component (B-2), the component (D), and the like. It is preferably 5 to 10 mPa · s, and more preferably.

Water-based ink:
The water-based ink of the present invention includes the above-described water-based carbon black dispersion of the present invention, water, a water-soluble organic solvent such as the component (D) or the component (E), a pH adjuster, a penetrant, It can be obtained by adding a known additive such as a surfactant and mixing. The aqueous ink of the present invention preferably contains 1 to 15% by mass of carbon black solid content in the aqueous carbon black dispersion. The viscosity of the aqueous ink of the present invention is preferably 2 to 10 mPa · s, and more preferably 3 to 7 mPa · s. The water-based ink obtained in the present invention can be preferably used as an ink for inkjet recording. The ink for inkjet recording using the water-based ink of the present invention is excellent in print quality, that is, print density and marker resistance when printed on media such as paper and OHP.

Method for producing aqueous carbon black dispersion:
The method for producing an aqueous carbon black dispersion of the present invention comprises (A) a (co) polymer containing a structural unit derived from a diene monomer or a (co) heavy containing a structural unit derived from a diene monomer. (B-1) carbon black having DBP absorption of 250 ml / 100 g or more, (B-2) DBP absorption of 250 ml / 100 g. Less than the carbon black is dispersed in the presence of (C) water and (D) acetylene alcohol to produce an aqueous carbon black dispersion.

  The components (A), (B), (C) and (D) used in the method for producing an aqueous carbon black dispersion of the present invention constitute the aqueous carbon black dispersion of the present invention described above (A ) Component, (B) component, (C) component, and (D) component, respectively, and it is preferable to manufacture by the same method. Moreover, it is preferable to use the method demonstrated in the aqueous | water-based carbon black dispersion liquid of this invention mentioned above also about the method of disperse | distributing each component.

  The aqueous carbon black dispersion obtained by the production method of the present invention is particularly useful for inkjet recording, but can also be used as other inks, for example, as ink for writing instruments such as general fountain pens, ballpoint pens, and sign pens. It is.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an Example and a comparative example are mass references | standards. Moreover, the various components used for an Example and a comparative example and various measurements were based on the following method.

(Example 1)
As shown in Table 1, polymer A8 parts by mass, carbon black B-1 (a) 2 parts by mass, carbon black B-2 (a) 13 parts by mass, 3-methyl-1-pentyne-3-ol 3 parts by mass and 74 parts by mass of water were premixed at room temperature and 500 rpm for 10 minutes using a three-one motor. 60 ml of premixed dispersion and 70 ml of 0.3 mm zirconia beads are charged into a diamond fine mill MD-1 type dispersing machine manufactured by Mitsubishi Heavy Industries, Ltd., and dispersed for 30 minutes at an internal temperature of 15 ° C. to 40 ° C. and a peripheral speed of 11 m / s. An aqueous carbon black dispersion was obtained. The viscosity and particle size of the aqueous carbon black dispersion were measured by the following methods. The results are shown in Table 2. On the other hand, 40 g of the resulting aqueous carbon black dispersion was mixed with 1 g of 3,5-dimethyl-1-hexyne-3-ol, 9 g of 3-methyl-1-pentyne-3-ol, and 50 g of water. A water-based ink (inkjet recording ink) was prepared. The obtained water-based ink was printed on commercially available plain paper XEROX 4200 (manufactured by XEROX) using an IJ printer MC2000 (manufactured by Seiko Epson), and the print quality was evaluated as follows. The results are shown in Table 3.

(Example 2)
4 parts by mass of B-1 (a), 11 parts by mass of B-2 (b) are used instead of B-2 (a), and instead of 3-methyl-1-pentyne-3-ol A water-based ink was obtained in the same manner as in Example 1, except that 3-methyl-1-butyne-3-ol was used to obtain a water-based carbon black dispersion. Then, the print quality was evaluated in the same manner as in Example 1.

(Example 3)
Polymer B is used instead of Polymer A, B-1 (b) is used instead of B-1 (a), and 3-methyl-1-pentyne-3-ol is used instead of 3-methyl-1-pent-3-ol. A water-based ink was obtained in the same manner as in Example 1 except that methyl-1-butyne-3-ol was used to obtain a water-based carbon black dispersion. Then, the print quality was evaluated in the same manner as in Example 1.

Example 4
A water-based ink was obtained in the same manner as in Example 1 except that the polymer C was used instead of the polymer A, and B-1 (b) was used instead of B-1 (a). Then, the print quality was evaluated in the same manner as in Example 1.

(Example 5)
A water-based ink was obtained in the same manner as in Example 1 except that a water-based carbon black dispersion was obtained without using 3-methyl-1-pentyne-3-ol. Then, the print quality was evaluated in the same manner as in Example 1.

(Comparative Example 1)
A water-based ink was obtained in the same manner as in Example 1 except that the polymer D was used instead of the polymer A. Then, the print quality was evaluated in the same manner as in Example 1.

(Comparative Example 2)
A water-based ink was obtained in the same manner as in Example 1 except that B-1 (a) was not used and 15 parts by mass of B-2 (a) was used. Then, the print quality was evaluated in the same manner as in Example 1.

(Comparative Example 3)
A water-based ink was obtained in the same manner as in Example 1 except that 15 parts by mass of B-1 (a) was used and B-2 (a) was not used. Then, the print quality was evaluated in the same manner as in Example 1.

(Comparative Example 4)
As shown in Table 1, polymer A8 parts by mass, carbon black B-1 (a) 2 parts by mass, carbon black B-2 (a) 13 parts by mass, 1,2-hexanediol 3 parts by mass, and water 74 Mass parts were premixed at room temperature and 500 rpm for 10 minutes using a three-one motor. 60 ml of premixed dispersion and 70 ml of 0.3 mm zirconia beads were charged into a diamond fine mill MD-1 type dispersing machine manufactured by Mitsubishi Heavy Industries, Ltd., and dispersed for 30 minutes at an internal temperature of 15 to 40 ° C. and a peripheral speed of 11 m / s. An aqueous carbon black dispersion was obtained. The viscosity and particle size of the aqueous carbon black dispersion were measured by the following methods. The results are shown in Table 2. On the other hand, 10 g of triethylene glycol monobutyl ether and 50 g of water were mixed with 40 g of the obtained aqueous carbon black dispersion to prepare an aqueous ink (ink jet recording ink). The obtained water-based ink was printed on commercially available plain paper XEROX 4200 (manufactured by XEROX) using an IJ printer MC2000 (manufactured by Seiko Epson), and the print quality was evaluated as follows.

1. Polymer (dispersant (component A))
Polymer A: Isoprene (IP) / styrene (ST) (50/50 molar ratio) sulfonated block copolymer (sulfonated isoprene unit), sulfonic acid (salt) group content 1.5 mmol / g, Mw 10 , 000

  Polymer B: IP / ST / IP / ST / IP (30/15/10/15/30 molar ratio) sulfonated product of quaternary block copolymer (sulfonated isoprene unit), sulfonic acid (salt) group content 1.1 mmol / g, Mw 20,000

  Polymer C: 15 mol% sulfonated product (sulfonated styrene unit) of hydrogenated IP / ST (50/50 molar ratio) block copolymer, sulfonic acid (salt) group content 1.2 mmol / g, Mw 6,000, hydrogenation rate 99%

  Polymer D: Bremmer-PE200 (manufactured by NOF Corporation, polyethylene glycol monomethacrylate) / acrylic acid / styrene (25/30/45 molar ratio) random copolymer, Mw 10,000, acid value 140

2. Carbon black (B-1 component, B-2 component)
B-1 (a): Printex XE2B (manufactured by Degussa), DBP absorption amount: 380 ml / 100 g, specific surface area: 950 m ² / g

B-1 (b): Blackpearls 2000 (manufactured by Cabot), DBP absorption amount: 330 ml / 100 g, specific surface area: 1475 m ² / g

B-2 (a): Color Black FW18 (manufactured by Degussa), DBP absorption amount: 160 ml / 100 g, specific surface area: 260 m ² / g

B-2 (b): Vulcan XC72 (manufactured by Cabot), DBP absorption amount: 174 ml / 100 g, specific surface area: 254 m ² / g

3. Measurement Carbon black particle size;
The number average particle size of carbon black contained in each of the obtained aqueous carbon black dispersion and aqueous ink was measured using Photo PAR-III manufactured by Otsuka Electronics Co., Ltd.

viscosity;
Using the Toki Sangyo E-type viscometer, RE-80L, the viscosity of the obtained aqueous carbon black dispersion and aqueous ink was measured.

Storage stability of water-based inks;
The obtained ink was sealed and stored in a glass container with a stopper at 70 ° C. for 2 weeks. The viscosity at 25 ° C. before and after storage was measured with the above viscometer, and the following determination was made.
○: The difference in viscosity before and after storage is less than 0.5 mPa · s Δ: The difference in viscosity before and after storage is 0.5 to 1 mPa · s
×: The difference in viscosity before and after storage exceeds 1 mPa · s

Print density;
The optical density (OD value) of the printed matter was measured with a Macbeth densitometer.

Marker resistance;
The printed matter was marked using a commercially available water-based marker (cocktail line (yellow) (Pentel Co., Ltd.). The same part was marked three times with the same strength, and whether or not the black color of carbon black was transferred to the water-based marker. The marker resistance was judged.
○: Marker does not get black and dirty even after 3 markings △: Marker does not get dirty with 1st marking, but marker becomes black with 2nd marking × × Marker becomes black with 1st marking

Discharge stability:
The obtained water-based ink was continuously printed on 20 sheets of plain paper XEROX 4200 (manufactured by XEROX) using IJ printer MC2000 (manufactured by Seiko Epson). The printed state of 20 printed sheets was visually observed, and the ejection stability was evaluated by whether or not there was a blur (portion where ink was not placed) having a width of 0.5 mm or more.
○: “Blurred” does not occur on all 20 sheets Δ: “Blurred” occurs on 1 to 2 out of 20 sheets ×: 3 or more “blured” out of 20 sheets

  As shown in Table 3, aqueous inks using the aqueous carbon black dispersions of Examples 1 to 5 have low viscosity, high print density of printed matter on plain paper, excellent marker resistance, and storage stability. It is found that the ink jet ink is excellent in ejection stability and exhibits excellent characteristics as an inkjet ink. On the other hand, the water-based ink of Comparative Example 1 is inferior in storage stability, ejection stability, printing density of plain paper, and marker resistance of printed matter because the polymer D is used as the dispersion polymer. Met. Since the water-based ink of Comparative Example 2 did not use (B-1) carbon black, the print density of the printed matter was low. Since the water-based ink of Comparative Example 3 did not use (B-2) carbon black, the viscosity was high and the storage stability and the marker resistance of the printed matter were poor. Since the water-based ink of Comparative Example 4 did not use acetylene alcohol, the ink viscosity, print density, and ejection stability were inferior.

  With the aqueous carbon black dispersion of the present invention, the aqueous ink of the present invention having a small particle diameter, low viscosity, good storage stability, and good ejection stability can be obtained. The water-based ink of the present invention can be suitably used as an ink for ink jet recording because it has excellent printing characteristics when printed on plain paper.

Claims (7)

(A) A (co) polymer containing a structural unit derived from a diene monomer or a hydrogenated product of a (co) polymer containing a structural unit derived from a diene monomer and having a sulfonic acid group Or a polymer having a salt thereof,
(B-1) Carbon black having a DBP absorption of 250 ml / 100 g or more,
(B-2) Carbon black having a DBP absorption of less than 250 ml / 100 g,
An aqueous carbon black dispersion containing (C) water and (D) an acetylene alcohol represented by the following general formula (1).

(R ¹ and R ² are hydrogen or an alkyl group having 1 to 10 carbon atoms. R ¹ and R ² may be the same or different.)   The (B-1) carbon black having a DBP absorption of 250 ml / 100 g to 500 ml / 100 g, and the (B-2) carbon black having a DBP absorption of 130 ml / 100 g to 230 ml / 100 g. An aqueous carbon black dispersion described in 1.   The mass ratio between the component (B-1) and the component (B-2) is (B-1) / (B-2) = 5/95 to 40/60. An aqueous carbon black dispersion described in 1.   The aqueous carbon black dispersion according to any one of claims 1 to 3, wherein the carbon black ((B-1) and (B-2)) contained has a number average particle diameter of 50 to 250 nm.   (A) A (co) polymer containing a structural unit derived from a diene monomer or a hydrogenated product of a (co) polymer containing a structural unit derived from a diene monomer and having a sulfonic acid group Or a polymer having a salt thereof, (B-1) carbon black having a DBP absorption of 250 ml / 100 g or more, (B-2) carbon black having a DBP absorption of less than 250 ml / 100 g, (C) water and (D ) A method for producing an aqueous carbon black dispersion which is dispersed in the presence of acetylene alcohol.   An aqueous ink containing the aqueous carbon black dispersion according to any one of claims 1 to 4.   The water-based ink according to claim 6, which is used as an ink for inkjet recording.