JP2001214089A - Carbon black for ink-jet recording liquid and ink-jet recording liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording liquid excellent in storage stability, jetting stability and inking density and also excellent in the resistance to scratching of printed matter. SOLUTION: This ink-jet recording liquid is prepared by using carbon black subjected to resin coating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon black for an ink jet recording liquid and an ink jet recording liquid, and more particularly, to a printed matter having extremely excellent scratch resistance while maintaining excellent print density and dischargeability. The present invention relates to carbon black for an inkjet recording liquid and an inkjet recording liquid that can be obtained.

[0002]

2. Description of the Related Art Conventionally, as a recording liquid for ink jet recording, an aqueous ink in which an acidic dye or a direct dye is dissolved in an aqueous medium, or a solvent-based ink in which an oil-soluble dye is dissolved in an organic solvent has been used. . Since the solvent-based ink uses a solvent, it has a problem in terms of environmental safety, and its use is limited because it is not suitable for use in offices and homes. A common water-based ink uses a water-soluble dye (dye), and has a problem that the printed matter has insufficient water resistance and light resistance.

In order to solve this problem, a pigment having excellent water resistance and light resistance is used as a coloring material, and an aqueous dispersion ink in which the pigment is dispersed in an aqueous medium is used. The aqueous pigment-dispersed ink for ink-jet recording has a problem in that the amount of the dispersant resin added is extremely small as compared with other pigment inks in order to ensure ejection stability and storage stability, and the abrasion resistance is poor. If a large amount of a water-soluble resin such as a polymer dispersant is added to the ink, the abrasion resistance can be improved, but there is a problem that the ejection stability, which is a necessary condition for the ink for inkjet recording, is impaired. Heretofore, an ink satisfying all of these characteristics has not been obtained.

Further, it is known that the primary particle diameter of carbon black is preferably smaller in order to ensure the storage stability of the ink jet recording liquid. Since the surface area of such carbon black increases at the same time, the amount of the dispersant required for dispersing also inevitably increases,
As a result, there is a problem that the ejection stability and the storage stability deteriorate.

[0005]

SUMMARY OF THE INVENTION The present invention provides storage stability,
It is an object of the present invention to provide a carbon black which provides an inkjet recording liquid having excellent ejection stability and excellent scratch resistance of a printed matter, and an inkjet recording liquid using the carbon black.

[0006]

The present inventors have conducted various studies on carbon black for an ink jet recording liquid and an ink jet recording liquid containing the carbon black.
By using surface-treated carbon black with the surface of carbon black coated with a resin, excellent ejection stability, storage stability, and recording density can be ensured, and the scratch resistance of the printed matter surface recorded by the inkjet method can be improved. It has been found that an extremely excellent recording liquid can be obtained. In other words, fine irregularities existing on the surface of the carbon black are covered with the resin, and the surface area of the carbon black is reduced. As a result, the amount of the dispersant required for dispersion is relatively reduced, resulting in storage stability and ejection stability. At the same time, the ink-jet recording liquid prepared using this carbon black has excellent abrasion resistance because it can form a resin coating film in the process of drying on paper by including a resin component. Reached the present invention. That is, the gist of the present invention is to provide a carbon black for an ink jet recording liquid characterized by coating carbon black with a resin, and an ink jet recording liquid containing the carbon black.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the carbon black used in the present invention, carbon black such as acetylene black, channel black, and furnace black can be used, but channel black and furnace black are preferable, and furnace black is particularly preferable. The carbon black used in the present invention preferably contains a large amount of volatile matter because it has a high affinity for the resin to be coated, and the content of the volatile matter per nitrogen adsorption specific surface area of the carbon black is preferably 0.01%.
% By weight / g / m ² or more, more preferably 0.02% by weight / g / m ² or more. When the content of volatile matter per nitrogen adsorption specific surface area of carbon black is less than 0.01% by weight / g / m ² , the number of reactive adsorption points of the resin present on the carbon black surface decreases, and Tends to be unable to be covered tightly with resin, and the resulting recording liquid may have insufficient scratch resistance on the printed surface.

The so-called acidic carbon black having a pH of 6 or less has a high density of reactive adsorption sites of the resin present on the surface of the carbon black. It is preferably used because the dispersed particle diameter (agglomerate diameter) becomes fine and the resin can be coated over a fine structure of carbon black. Such a carbon black having a high volatile content per unit specific surface area or an acidic carbon black having a pH of 6 or less can be obtained by manufacturing in an oxygen atmosphere, or a neutral carbon black obtained by manufacturing in an inert atmosphere. Can also be obtained by subsequent oxidation using an oxidizing agent such as hydrogen peroxide or ozone.

Preferably, the ash content of the carbon black is 1.0% by weight or less. The composition of the ash is an alkali (earth) metal salt such as sodium, potassium, calcium and the like. As a method for reducing these, as a raw material oil or a fuel oil (or gas) and a reaction stopping water for producing carbon black. As examples, it is possible to select those having the smallest possible content, and to minimize the addition amount of the alkali substance for adjusting the structure. As another method, there is a method in which carbon black produced from a furnace is washed with water, hydrochloric acid, or the like, and alkali (earth) metal ions such as sodium and potassium are dissolved and removed. Specifically, after mixing and dispersing carbon black in water or hydrochloric acid, hydrogen peroxide water, when a solvent that is hardly soluble in water is added, the carbon black moves to the solvent side and is completely separated from water. At the same time, most of the alkali (earth) metal ions present in carbon black are dissolved in water and acids,
Removed. The ash content can be reduced by selecting raw materials in the carbon black production step and washing with water or an acid, and can be more easily achieved by using both together. If the ash content exceeds 1.0% by weight, the storage stability of the obtained inkjet recording liquid tends to deteriorate. The primary particle size of carbon black is 2
The thickness is preferably 0 nm or less, preferably 16 nm or less, and more preferably 15 nm or less. Primary particle size is 20nm
When it exceeds, the storage stability of the obtained inkjet recording liquid tends to deteriorate.

In the present invention, the ash content of carbon black is 1.
It is particularly preferred that the content is 0% by weight or less and the primary particle size is 20 nm or less. The volatile matter, nitrogen adsorption specific surface area, and ash content of carbon black referred to in the present invention are JIS K622.
The primary particle size refers to the arithmetic mean size (number average) measured by an electron microscope, and the pH refers to the pH value of a slurry obtained by boiling a carbon black aqueous suspension and then cooling.

As specific examples of the above carbon black, Mitsubishi Carbon Black # 2700, # 265
0, # 2450B, # 2400B, # 2350, # 22
00, # 1000, # 970, MA77, MA7, MA
8, MA11, MA100, MA100R, MA100
S, MA230, MA200, MA200RB, MA1
4 (Mitsubishi Chemical Corporation), ColorBlack F
W1, FW2, FW2V, FW18, FW200, S1
70, SpecialBlack6 (products of Degussa), CONDUCTEX 975 ULTRA (Colombian products), and the like.

The carbon black used in the recording liquid of the present invention may be obtained by chemically treating the above-described carbon black (oxidation treatment, fluorination treatment, etc.), dispersing agent, surfactant and the like. Alternatively, those chemically bonded (grafting treatment, one in which a dispersant is previously adsorbed before dispersion, or the like) may be used. The type of resin used for coating the carbon black is not particularly limited, but may be any one that does not dissolve in a dispersion medium described below, and may be a thermoplastic resin or a thermosetting resin. It may be.

Representative examples of the thermoplastic resin include polyvinyl chloride resins such as polyvinyl chloride, polyvinylidene chloride, and vinyl chloride-vinyl acetate copolymer; polyvinyl acetate resins such as polyvinyl acetate; polystyrene Polystyrene resins such as polyethylene, polypropylene and ethylene-vinyl acetate copolymer; polyamide resins such as nylon-6 and nylon-6,6; polymethyl (meth) acrylate;
Acrylic resins such as silicone acrylic resins; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonates, cellulose resins, polyacetals, polyphenylene oxides,
Examples include a noryl resin, a polysulfone, a fluorine-based resin, a silicon-based resin, an ABS resin, polyphenylene sulfide, polyimide, polyimide amide, and polydiphenyl ether. These can be used alone or in combination of two or more. Among them, fluorine-based resin, silicon-based resin, silicone acrylic resin, polyimide, polyimide amide, polydiphenyl ether, and the like are preferable.

Representative examples of the thermosetting resin include, for example, a phenol resin, a urea resin, a melamine resin, a xylene resin, a diallyl phthalate resin, an epoxy resin, a urethane resin, and a benzoguanamine resin. A mixture of more than one species can be used. Among them, epoxy resin, urethane resin and the like are particularly preferable in that they have excellent coatability.

Above all, a resin having a benzene nucleus in the structure is particularly preferably used because of its excellent affinity with carbon black. As the resin used for the coating treatment of carbon black, a resin that can react with a functional group present on the surface of carbon black is preferable because it has high affinity and a uniform coating can be easily formed. Specifically, a resin having a functional group capable of forming a bond such as a hydrogen bond, an acid-base bond, or a covalent bond with a functional group such as a carboxyl group or a phenolic hydroxyl group present as a volatile component on the carbon black surface, that is, a carboxyl group , Hydroxyl group, glycidyl group,
Urethane group, isocyanate group, amino group, amide group,
A resin having an amine oxide group, a betaine group or the like in the structure is preferable. Such a resin is preferable because desorption of the resin once adsorbed is suppressed. Particularly, an epoxy resin having a glycidyl group and a urethane resin having a urethane group or an isocyanate group are preferable, and those having the above functional groups are more preferable. Specific examples of the epoxy resin include glycylamine epoxy resin, triphenylglycidylmethane epoxy resin, tetraphenylglycidylmethane epoxy resin, aminophenol epoxy resin, diamidediphenylmethane epoxy resin, phenol novolak epoxy resin, and orthocresol epoxy resin Epoxy resin, bisphenol A novolak type epoxy resin and the like, as specific examples of urethane resin,
Examples thereof include a polyester-based urethane resin and a polyether-based urethane resin.

As the resin used for coating the carbon black, a resin containing both a hydrophilic functional group and a hydrophobic functional group as essential components in the structure can be preferably used. As such a resin, a known resin generally used as a nonionic polymer dispersant or an ionic polymer dispersant can be used. As the nonionic polymer dispersant, those having an ethylene oxide structure or a propylene oxide structure as a hydrophilic functional group are particularly preferable. Specific examples of the nonionic polymer dispersant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether,
Polyoxyethylene alkyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene alkylamine, amino polyoxyethylene, sorbitan fatty acid Ester, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan oleate, naphthol ethylene oxide adduct, acetylene glycol ethylene oxide adduct, bisphenol A ethylene oxide adduct, oxyethylene oxy Propylene block polymer, sorbitan fatty acid ester, polio Shi sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, can be exemplified polyoxyethylene alkyl amines.

Examples of the ionic polymer dispersant include a cationic polymer dispersant having a cationic functional group, an amphoteric polymer dispersant having an amphoteric group, and an anion having an anionic functional group. A system polymer dispersant can be used. Specific examples of the cationic functional group include an alkylamine (salt) group and a quaternary ammonium (salt) group.
Specific examples of the zwitterionic functional group include an alkyl betaine group and an amine oxide group. Specific examples of the anionic functional group include a carboxylic acid (salt) group, a sulfonic acid (salt) group, and a phosphoric acid (salt) group. Examples of the hydrophobic group contained in the nonionic polymer dispersant and / or the ionic polymer dispersant include a functional group having an aromatic ring such as a phenyl group, a benzyl group, and a naphthyl group, and a straight group having 4 or more carbon atoms. Examples thereof include a chain or branched optionally substituted alkyl group, alkenyl group, and alkynyl group. One of these functional groups may be contained in the structure of the resin, or two or more thereof may be contained.

As the ionic polymer dispersant, an anionic polymer having an anionic functional group selected from a carboxylic acid (salt) group, a sulfonic acid (salt) group and a phosphoric acid (salt) group is particularly preferably used. Can be. Specific examples of such an anionic polymer include styrene, α-methylstyrene, aliphatic hydrocarbon and / or aromatic hydrocarbon ester of (meth) acrylic acid, and aliphatic hydrocarbon and / or aromatic hydrocarbon of maleic acid. A hydrophobic vinyl monomer unit such as an aromatic hydrocarbon ester and (meth) acrylic acid, maleic acid,
Water-based acrylic resin containing an anionic vinyl monomer unit such as acrylamide-2-methylpropanesulfonic acid and / or a salt thereof as a constituent, anionic polyester-based urethane resin, anionic polyether-based urethane resin, and the like A preferred example is an aqueous urethane resin. These polymer dispersants may be used alone or in combination of two or more. Further, other additives such as a surface tension adjuster and a preservative may be used in the recording liquid of the present invention.

Examples of commercially available polymer dispersants, polymer dispersant solutions or polymer dispersant emulsions as described above include Joncryl 67, 678, 680 and
682, 690 and / or a salt thereof, Joncryl 5
2, 57, 60, 62, 63, 70, 354, 501,
Specific examples include 6610 (all manufactured by Johnson Polymer), Hydran HW series, and Hydran AP series (all manufactured by Dainippon Ink and Chemicals). The amount of the resin coated on the carbon black is preferably 1 to 30% by weight based on the total amount of the carbon black and the resin. If the amount is less than 1% by weight, the abrasion resistance of the ink jet recording liquid obtained will be insufficient, and if it exceeds 30% by weight, the resins will fuse together, making it difficult to disperse the carbon black during the production of the ink jet recording liquid. There is.

The method of coating the carbon black with the resin is not particularly limited. For example, after appropriately adjusting the compounding amounts of the carbon black and the resin, (1) mixing the resin with a solvent such as cyclohexanone, toluene and xylene; The resin solution dissolved by heating and the suspension obtained by mixing carbon black and water are mixed and stirred, and after separating the carbon black and water, the water is removed and the composition obtained by heating and kneading is mixed. (2) mixing and stirring the resin solution and the suspension prepared in the same manner as above to granulate the carbon black and the resin, and then forming the granules into a sheet; (3) dissolving a carboxylic acid such as maleic acid or fumaric acid in the solvent exemplified above; Bonn black is added, mixed and dried, and the solvent is removed to obtain a carboxylic acid-impregnated carbon black, and then a resin is added thereto for dry blending; (4) a reactive group containing the resin to be coated A monomer component and water are stirred at high speed to prepare a suspension, and after polymerization, the mixture is cooled and a reactive group-containing resin is obtained from the polymer suspension. And a reactive group (grafting carbon black), followed by cooling and pulverization.

Above all, the coating method (2) is preferable since the particle size of the carbon black can be made uniform and the particle size can be reduced. The carbon black coated with the resin according to the present invention can be used as an inkjet recording liquid by dispersing it in an aqueous medium by an ordinary method. For dispersion, a known dispersant may be appropriately added to the recording liquid. Dispersants preferably used in the present invention include various anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants,
And a polymeric dispersant. The use of a polymeric dispersant is particularly preferred, since the printed matter formed by the obtained recording liquid has extremely good scratch resistance.

Specific examples of the anionic surfactant include:
Fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl aryl sulfate salts Salts, alkanesulfonic acid salts, naphthalenesulfonic acid formalin condensates, polyoxyethylene alkyl phosphates,
N-methyl-N-oleoyl taurate, α-olefin sulfonates and the like. Specific examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts, and examples of the amphoteric surfactant include alkylbetaines and amine oxides.

As the nonionic surfactant, those similar to the nonionic polymer dispersants exemplified as the resin used for coating the carbon black can be preferably used. Among them, a nonionic additive having an ethylene oxide structure or a propylene oxide structure is preferable in terms of storage stability and print density, and among them, those having an HLB of 9 to 17 are more preferable. Among them, those having an HLB of 10 to 16 are particularly preferable.

The ionic polymer dispersant used in the present invention is not particularly limited, but copolymer polymers such as block copolymers, graft copolymers, and random copolymers are preferably used. Copolymers, random copolymers are more preferred,
Random copolymers are particularly preferably used. The weight average molecular weight of these polymers is preferably 50,000 or less, and those having 15,000 or less are more preferably used. When the weight average molecular weight exceeds 50,000, the ejection stability of the obtained recording liquid may be deteriorated.

As the polymer dispersant, carboxylic acid (salt)
Group, an anionic polymer having an anionic functional group selected from a sulfonic acid (salt) group and a phosphoric acid (salt) group can be preferably used, and a hydrophobic group and / or an anionic functional group having a pKa of 3 or less can be used. Is particularly preferably used because the storage stability and ejection stability of the obtained recording liquid are improved. A polymer having a carboxylic acid (salt) group and / or a sulfonic acid (salt) group as the anionic functional group is particularly preferred because both the dispersibility of carbon black and the ejection stability of the obtained recording liquid are improved. Specific examples of the anionic polymer dispersant that can be used in the present invention include the same types as those exemplified as the anionic polymer dispersant used for coating the carbon black. These dispersants may be used alone or in combination of two or more. Further, other additives such as a surface tension adjuster and a preservative may be used in the recording liquid of the present invention. The aqueous medium used for the recording liquid of the present invention is mainly composed of water, but it is preferable to add a water-soluble organic solvent to water before use. Examples of the water-soluble organic solvent include ethylene glycol, propylene glycol, 1,3-propanediol, butylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol (# 20).
0, # 300, # 400, # 4000, # 6000),
Glycerin, ethylene glycol adducts of glycerin (specific examples: Liponic EG-1 manufactured by Lipochemical Co., Ltd.), alkyl ethers of the above glycols (diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, diethylene glycol monopropyl ether, triethylene Glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether, polyethylene glycol monostearyl ether, etc.), N-methylpyrrolidone, 1,3
-Dimethylimidazolinone, thiodiglycol, 2-pyrrolidone, sulfolane, dimethylsulfoxide, diethanolamine, triethanolamine, methanol, ethanol, isopropanol, neopentyl alcohol, trimethylolpropane, 2,2-dimethylpropanol and the like. One of these water-soluble organic solvents may be used alone, or two or more thereof may be used.

In addition to the above-mentioned components, a water-soluble resin, a fungicide, a bactericide, a pH adjuster, urea, and the like may be added to the recording liquid of the present invention as needed. As a dispersing machine for preparing the recording liquid of the present invention, in addition to a ball mill, a roll mill, and a sand grind mill, a jet mill such as a nanomizer that can be pulverized without using a medium and an optimizer is used. Alternatively, a jet mill with less contamination from media is preferred. After this grinding and dispersion treatment, coarse particles are removed using a filter or a centrifuge. Also, milling and dispersion can be performed efficiently by preparing at a high concentration,
The processing liquid prepared at a high concentration may be diluted with an aqueous medium to adjust the concentration of the recording liquid.

The average particle size of the water-insoluble coloring material in the recording liquid is preferably adjusted to a range of 0.01 to 0.4 μm from the viewpoint of dispersion stability and ejection stability. .
3 μm is more preferable, and 0.1 to 0.3 μm is particularly preferable. Further, the maximum particle size of the water-insoluble coloring material is preferably 5 μm or less from the viewpoint of dispersion stability and ejection stability. The amount of carbon black used in the recording liquid is preferably in the range of 1 to 20% by weight based on the total weight of the recording liquid, and is preferably 3 to 20% by weight.
To 15% by weight, more preferably 3 to 10% by weight.
The amount of the dispersant is usually in the range of 2 to 100% by weight based on the weight of carbon black, and preferably 3 to 5%.
0% by weight, more preferably 10 to 20% by weight. The amount of the polymer used as the dispersant and the abrasion resistance improver is preferably in the range of 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, based on the total weight of the recording liquid.

The amount of the water-soluble organic solvent used in the recording liquid is 5 to 5.
Although it is in the range of 30% by weight, 5 to 20% by weight is preferable in terms of storage stability, and 8 to 20% by weight is particularly preferable. One type of these carbon blacks, resins, dispersants, additives, and organic solvents may be used alone, or two or more types may be used in some cases.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the following examples, “parts” and “%” are based on weight.

[Example 1] (Production of resin-coated carbon black) Carbon black was prepared in the usual manner except that a raw material oil containing little Na, Ca and S was used, and water treated with an ion-exchange resin was used as a reaction stopping water. It was manufactured in accordance with the oil furnace method. 100 g of the obtained carbon black A is 10 cm in inner diameter and 10 c in length.
m, and contacted with a mixed gas of air and ozone (6000 ppm of ozone) for a certain period of time so as to have a volatile content of 4.6% by weight while rotating at 9 rpm to obtain carbon black B. Table 1 shows the physical properties of carbon black. 120 g of carbon black B is added to pure water 5000
g together with a homomixer to obtain a slurry. Transfer this slurry to a container with a screw type stirrer,
While stirring, a solution in which 14 g of an epoxy resin “Epicoat 828” (product of Yuka Shell Epoxy Co., Ltd.) was dissolved in 400 mL of toluene was added little by little. In about 15 minutes, all the carbon black dispersed in the water migrated to the toluene side,
A granular mass about 1 mm in diameter was formed. Next, after draining with a 60-mesh wire net, it was placed in a vacuum dryer and dried at 70 ° C. for 7 hours to remove toluene and water, thereby obtaining resin-coated carbon black C. (Adjustment of recording liquid)

[0031]

Table 1 Composition of recording liquid Amount used (parts) Resin-coated carbon black C 4.6 Styrene / acrylamide-2-methylsulfonic acid / acrylic acid copolymer (random copolymer, monomer weight ratio = 50/30/20) Ammonium salt of sodium salt having a weight average molecular weight of 8000) 0.4 1,3-dimethyl-2-imidazolidinone 4.0 ion-exchanged water 35 total 44

Each of the above components was placed in a cylindrical stainless steel container, and subjected to a dispersion treatment for 3 hours using a sand grinder together with 67 parts of zirconia beads having an average diameter of 0.5 mm. 4 parts of glycerin, 3 parts of ethanol and 49 parts of ion-exchanged water were further added to the obtained liquid. This solution was
Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid.

(Printing test) The recording liquid obtained by the method described in the above embodiment was applied to a printer manufactured by NEC "Picty 70".
No. 0 "ink cartridge, and the printer was used to print electrophotographic paper" Xerox 4024 "(US X
(Erox product). As a result, a stable and good ejection property without clogging or the like was exhibited, and a printed matter having good print quality was obtained. Separate glossy film for inkjet "MJA4SP6" for evaluation of coating film adhesion
(Seiko Epson) was also prepared.

(Evaluation of print density) X obtained in the above print test
The density (OD value) of the printed matter on erox 4024 paper was measured using a Macbeth reflection densitometer (RD914). If the OD value is 1.2 or more, it can be determined that the print density is good. The results are shown in Table 2 below.

(Line Marker Test) As an index of scratch resistance, the printed surface of the printed matter on Xerox 4024 paper obtained in the above printing test was rubbed with a yellow line marker, and the presence or absence of character stain was visually evaluated. The results were classified as follows and are shown in Table 2 below. : There is almost no character stain, and the scratch resistance is excellent. Δ: Although there is a slight character stain, there is no practical problem and the scratch resistance is good. X: Practically problematic, character stain was severe to some extent, and scratch resistance was poor.

(Coating film adhesion test) As an index of abrasion resistance, the printed surface of the "MJA4SP6" printed material obtained in the above printing test was rubbed with a metallic spatula, and the presence or absence of peeling of the printed surface was visually evaluated. . The results were classified as follows and shown in Table 2 below. : The printed surface is not peeled off, and the scratch resistance is excellent. Δ: The printed surface hardly peeled off, and the scratch resistance was good. ×: The printed surface peeled off, causing a practical problem, and the scratch resistance was poor.

(Measurement of Dispersion Particle Size) The obtained recording liquid is diluted with ion-exchanged water, and then the particle size is measured using a particle size analyzer (particle analyzer N).
4S (Coulter's product)).

[0038]

[Table 2] Measurement conditions Temperature = 25 degree Viscosity = 0.894 cP Refractive Index = 1.333 Angle = 90.0 degrees Sample Time = 13.5 micro-sec Pre-scale = 2 Run Time = 60 seconds

The average of three measurements under the above measurement conditions was taken as the average dispersed particle diameter of the recording liquid. The average dispersion particle diameter of the recording liquid obtained in Example 1 was 0.156 μm.
m.

(Storage stability test)
C. for 1 week, and after returning to room temperature after storage, use a particle size analyzer (particle analyzer N4S (Cou
lter product))) and the particle size was measured in the same manner as described above. The obtained result was compared with the result of the particle diameter measurement test to calculate the difference in the average particle diameter. If the difference is 10% or less, it is considered that the storage stability is good.

Example 2 (Production of Resin-Coated Carbon Black) An aqueous dispersion of an aqueous urethane resin “Hydran HW140” (manufactured by Dainippon Ink and Chemicals, Inc.) was added to 120 g of carbon black B while stirring, in an amount of 14 g in terms of solid content. The mixture was dropped and sufficiently stirred using a household juicer mixer. The obtained carbon black was placed in a vacuum dryer and dried at 70 ° C. for 7 hours, and water was distilled off to obtain a resin-coated carbon black D.

(Preparation of Recording Liquid) A recording liquid was prepared in the same manner as in Example 1, except that the resin-coated carbon black D was used instead of the resin-coated carbon black C. The same evaluation as in the above example was performed using the obtained recording liquid. The results are shown in Table 2 below. The average dispersion particle diameter of the recording liquid measured by the same method as in Example 1 was 0.1.
It was 36 μm. [Example 3] (Production of resin-coated carbon black) Production was carried out in the same manner as in Example 1 except that water-based acrylic resin "Johncryl 450" was used instead of aqueous urethane resin "Hydran HW140" in Example 2. Was carried out to obtain a resin-coated carbon black E. (Preparation of Recording Liquid) A recording liquid was prepared in the same manner as in Example 1 except that the resin-coated carbon black E was used instead of the resin-coated carbon black C. The same evaluation as in the above example was performed using the obtained recording liquid. The results are shown in Table 2 below. The average dispersion particle diameter of the recording liquid measured by the same method as in Example 1 was 0.128 μm. [Comparative Example 1] Instead of using resin-coated carbon black C in Example 1, carbon black A without resin coating was used.
A recording liquid was prepared in the same manner as in Example 1 except that The same evaluation as in the above example was performed using the obtained recording liquid. The results are shown in Table 2 below. The average dispersion particle diameter of the recording liquid measured by the same method as in Example 1 was 0.156 μm.
m.

[0043]

[Table 3]

[0044]

[Table 4]

From Tables 1 and 2, it can be seen that the ink jet recording liquid prepared by using the resin-coated carbon black has extremely excellent abrasion resistance while maintaining excellent ejection properties, print density and storage stability. (Line marker test, coating film adhesion test) are shown (Examples 1 to 3). On the other hand, it can be seen that the inkjet recording liquid prepared using ordinary carbon black A not subjected to the surface treatment has good ejection properties, print density, storage stability, etc., but has extremely poor abrasion resistance ( Comparative example 1).

[0046]

According to the present invention, there is provided a carbon black which provides an ink jet recording liquid which is excellent in storage stability, ejection stability, print density and extremely excellent in abrasion resistance of a printed matter. The used inkjet recording liquid can be provided, and its industrial utility value is extremely high.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideyuki Hisa 1 Tohocho, Yokkaichi-shi, Mie F-term (reference) in Yokkaichi Office of Mitsubishi Chemical Corporation 4J037 AA02 CC23 CC26 DD05 DD27 EE03 EE28 EE43 EE46 FF05 FF18 FF23 FF30 4J039 AE04 AE05 BA04 BE01 CA06 EA36 GA24

Claims (9)

[Claims] 1. A carbon black for an inkjet recording liquid, wherein the carbon black is coated with a resin. 2. The carbon for an ink jet recording liquid according to claim 1, wherein the carbon black has a volatile matter content per nitrogen adsorption specific surface area of 0.01% by weight · g / m ² or more. Gluck. 3. The carbon black for an ink jet recording liquid according to claim 1, wherein the pH of the carbon black is 6 or less. 4. The carbon black for an ink jet recording liquid according to claim 1, wherein the ash content of the carbon black is 1.0% by weight or less and the primary particle diameter is 20 nm or less. 5. The carbon black for an ink jet recording liquid according to claim 1, wherein said resin is a resin containing a benzene nucleus in its structure. 6. The resin has a carboxyl group, a urethane group, an isocyanate group, a carbonyl group, a hydroxyl group,
The carbon for an inkjet recording liquid according to claim 1, wherein the resin is a resin containing at least one functional group selected from the group consisting of a glycidyl group, an amino group, an amide group, an amine oxide group, and a betaine group. black. 7. The carbon black for an ink jet recording liquid according to claim 1, wherein said resin contains a resin selected from an epoxy resin and a urethane resin. 8. The carbon black for an ink jet recording liquid according to claim 1, wherein the coating amount of the resin is 1 to 30% by weight based on the total amount of the carbon black and the resin. 9. An aqueous pigment-dispersed ink containing carbon black and water, wherein the carbon black according to claim 1 is used.