JP4603756B2 - Ink composition for inkjet recording - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink composition for ink jet recording, and relates to an aqueous ink used in ink jet recording in which recording is performed on a recording material by ejecting and flying the ink using mechanical and thermal energy.
[0002]
[Prior art]
A so-called inkjet printer that discharges liquid ink from a nozzle, slit, porous film, etc., and records on paper, cloth, film, etc. has various advantages such as small size, low cost, and quietness. Many single-color or full-color printers are commercially available. Among them, the so-called piezo ink-jet method using a piezoelectric element and the so-called thermal ink-jet method in which droplets are formed by applying thermal energy to perform recording have many advantages such as high-speed printing and high resolution. Yes.
[0003]
Conventionally, inks using water-soluble dyes generally used in ink jet recording systems have problems in water resistance and light resistance. In contrast, pigment-based inks are very promising because they are excellent in water resistance and light resistance, and can obtain high-density and no-bleed image quality. In recent years, many proposals have been made and put into practical use. Has been.
[0004]
For example, Japanese Patent Application Laid-Open No. 56-147871 proposes a recording liquid comprising an aqueous medium containing a pigment, a polymer dispersant and a nonionic surfactant. In US Pat. Nos. 5,085,698 and 5,221,334, it is proposed to use a block copolymer as a pigment dispersant. Furthermore, in the said 5172133, using a specific pigment, water-soluble resin, and a solvent is proposed.
[0005]
Japanese Patent Application Laid-Open No. 6-92008 proposes to use an ink containing at least acetylene glycol having a contact angle of 40 degrees or less after 5 seconds of dropping with respect to sized paper.
[0006]
Japanese Patent Application Laid-Open No. 2000-144028 proposes a pigment ink having a dynamic contact angle change rate with time of 0.5 to 3.5 degrees / second on plain paper.
[0007]
[Problems to be solved by the invention]
According to an actual study by the inventors, when the pigment ink composition is printed on a paper having a low sizing degree, that is, a highly penetrating paper among uncoated papers, the print density is low or the density uniformity is impaired. That is, it has become clear that the problem of density unevenness occurs.
[0008]
The present invention solves the problems of the prior art, and has a high optical density when printed on plain paper, does not cause density unevenness and blurring, and contains an ink composition for inkjet recording that has excellent ejection stability. The purpose is to provide goods.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the inventors have intensively studied and found the present invention.The present invention comprises at least a pigment, a water-soluble organic solvent, a surfactant, and water.
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
c ) The nonionic surfactant is a fluorosurfactant, and the surface tension is 25 mN / m or more,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. And an ink composition for ink jet recording, wherein a plurality of these are mixed and used.
[0010]
Thereby, a high density and uniform printed matter can be obtained.
[0015]
Using ion-based surfactant when affecting the dispersion state of the pigment, while it may occur the aggregation and sedimentation, the present invention use a nonionic surfactant, and maintained the dispersion state of the pigment The surface tension can be adjusted.
[0017]
The fluorosurfactant has a high ability to lower the surface tension, but it tends to bleed when it is less than 25 mN / m. According to the present invention, it is possible to reduce the occurrence of bleeding.
[0018]
And this invention consists of at least a pigment, a water-soluble organic solvent, a surfactant and water,
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
d ) The nonionic surfactant is an acetylene glycol surfactant, and the surface tension is 35 to 45 mN / m,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. And an ink composition for ink jet recording, wherein a plurality of these are mixed and used.
[0019]
When an acetylene glycol-based surfactant is used, bleeding occurs when the surface tension is less than 35 mN / m, and ejection properties deteriorate when the surface tension is greater than 45 mN / m. In the present invention, it is difficult to cause such a phenomenon. be able to.
[0020]
Furthermore, the present invention comprises at least a pigment, a water-soluble organic solvent, a surfactant and water,
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
e ) The nonionic surfactant is a polyoxyalkylene ether surfactant, and the surface tension is 30 to 50 mN / m ,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. And an ink composition for ink jet recording, wherein a plurality of these are mixed and used.
[0021]
When a polyoxyalkylene ether-based surfactant is used, bleeding occurs when the surface tension is less than 30 mN / m, and when the surface tension is greater than 50 mN / m, the discharge property is deteriorated. Can be difficult.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
The ink composition for ink jet recording according to the present invention contains pigment, water-soluble organic solvent, surfactant and water as essential components, and 10 μl when 2 μl (micron liter) is dropped on plain paper having a Steechst size of 30 seconds or less. The dynamic contact angle after 2 seconds is 50.0 ° or more, and the time change rate of the subsequent dynamic contact angle is 0.8 ° / second or less. In addition, a water-soluble resin and other additives can be contained.
[0023]
Any pigment can be used as long as it has good affinity with water as the main solvent. For example, azo pigments such as carbon blacks, azo lakes, insoluble azo pigments, synthetic azo pigments, chelate azo pigments, phthalocyanine pigments, and quinacridone pigments. , Berelin, and berelin pigments, anthraquinone pigments, dioxazine pigments and other organic pigments, and aniline black. In addition, a pigment that can be self-dispersed in water can be used. A pigment that can be self-dispersed in water is a pigment that has a large number of hydrophilic groups on the surface of the pigment and can be stably dispersed even in the absence of a polymer dispersant. Specifically, by applying surface modification treatments such as acid / base treatment, coupling agent treatment, polymer graft treatment, plasma treatment, oxidation / reduction treatment, etc. to ordinary so-called pigments, self-dispersion in water Possible pigments can be obtained. As pigments that can be self-dispersed in water, in addition to pigments that have been surface-modified as described above, Cab-o-jet-200, Cab-o-jet-300, and IJX manufactured by Cabot Corporation. Commercially available pigments such as -55, Bonjet Black CW-1 and Bonjet Black CW-2 manufactured by Orient Chemical Co., Ltd., and pigments sold by Nippon Shokubai Co., Ltd. can be used.
[0024]
The solubilizing group present on the surface of the pigment self-dispersible in water may be any of nonionic, cationic or anionic, but is preferably sulfonic acid, carboxylic acid, hydroxyl group or phosphoric acid. In the case of sulfonic acid, carboxylic acid, and phosphoric acid, it can be used as it is in the free acid state, but it is preferably used in the form of a salt with a basic substance in order to enhance water solubility. Examples of basic substances that form salts with these polymers include alkali metals such as sodium, potassium and lithium, aliphatic amines such as monomethylamine, dimethylamine and triethylamine, monomethanolamine, monoethanolamine, diethanolamine, Examples thereof include alcohol amines such as triethanolamine and diisopropanolamine, and ammonia. Among these, basic compounds of alkali metals such as sodium, potassium and lithium are preferably used. This is presumably because the alkali metal basic compound is a strong electrolyte and has a large effect of promoting dissociation of acidic groups.
[0025]
The colorant used in the inkjet recording liquid of the present invention is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the weight of the inkjet recording liquid. If the amount of the coloring material is less than 0.5% by weight, sufficient image density cannot be obtained, and if it exceeds 10% by weight, the ink ejection property may be deteriorated.
[0026]
Next, the ink according to the present invention is mixed with a plurality of the following water-soluble organic solvents for the purpose of making the ink have desired physical properties, preventing drying of the ink, and improving dissolution stability. May be used. That is, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2 Polyhydric alcohols such as 1,4-butanetriol, 1,2,3-butanetriol, petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, Polyhydric alcohol alkyl ethers such as tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, ethylene glycol Polyhydric alcohol aryl ethers such as ethylene monophenyl ether, ethylene glycol monobenzyl ether, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε -Nitrogen-containing heterocyclic compounds such as caprolactam, amides such as formamide, N-methylformamide, formamide, N, N-dimethylformamide, amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine , Dimethyl sulfoxide, sulfolane, thiodiethanol, ethylene urea, urea and other sulfur-containing compounds, propylene carbonate, ethylene carbonate, γ-butyrolactone, etc. can be used alone or in combination. That.
[0027]
Polymeric dispersants or binders that can be used in the present invention include proteins such as gelatin, albumin, and casein, natural rubbers such as gum arabic, glucosides such as saponin, lignin sulfonates, shellac and other natural high polymers. Molecule, polyacrylate, polymethacrylate, styrene-acrylic acid copolymer and salt thereof, vinylnaphthalene-acrylic acid copolymer and salt thereof, and salt thereof, styrene-maleic acid-acrylic acid alkyl ester copolymer Polymers and salts thereof, vinyl naphthalene-maleic acid copolymers and salts thereof, styrene-methacrylic acid-acrylic acid alkyl ester copolymers and salts thereof, sodium salts of β-naphthalenesulfonic acid formalin condensates, phosphates, etc. Nonionics such as anionic polymers, polyvinyl alcohol, polyvinyl pororidone Polymer, more, acrylonitrile, vinyl acetate, acrylamide, vinyl chloride, vinylidene chloride, ethylene, hydroxyethyl acrylate, monomers such as glycidyl methacrylate may be copolymerized. These may be added singly or in combination.
[0028]
It is also possible to contain additives such as preservatives such as proxel, fungicides, pH adjusters, dissolution aids and antioxidants.
[0029]
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples unless the gist thereof is exceeded.
[0030]
Preparation of the pigment dispersion will be described.
(A) Preparation of pigment dispersion 1 Styrene-acrylic acid copolymer resin 4.0 parts by weight (weight average molecular weight = 7500, acid value = 200)
Triethanolamine 2.7 parts by weight Isopropyl alcohol 0.4 parts by weight Ion exchange water 72.9 parts by weight The above components were completely dissolved under heating at 70 ° C. Next, 20 parts by weight of carbon black (MA100, manufactured by Mitsubishi Chemical) was added to the above solution, and after premixing, the average particle size of carbon black was measured with a ball mill (zirconium bead filling ratio = 50%, bead diameter = 0.5 mm). Dispersion was performed until the diameter reached 150 nm, and a 1.2 μm filter was passed through to obtain Pigment Dispersion Liquid 1. Microtrac UPA (manufactured by Nikkiso Co., Ltd.) was used for measurement of the particle size.
[0031]
(B) Preparation of Pigment Dispersion Liquid 2 Dispersion was performed under the same composition and conditions as in the preparation of Pigment Dispersion Liquid 1 to obtain Pigment Dispersion Liquid 2 having an average particle diameter of carbon black of 65 nm.
[0032]
(C) Preparation of Pigment Dispersion 3 Dispersion was performed under the same composition and conditions as in the preparation of Pigment Dispersion 1 to obtain Pigment Dispersion 3 having an average particle size of carbon black of 300 nm.
[0033]
(D) Preparation of Pigment Dispersion 4 Dispersion was performed under the same composition and conditions as in the preparation of Pigment Dispersion 1 to obtain Pigment Dispersion 4 having an average particle size of carbon black of 50 nm.
[0034]
Example 1 will be described. The ink composition for ink jet recording of Example 1 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight Nonionic surfactant 0.1 part by weight (manufactured by Air Products) Surfinol 104E)
Polyethylene glycol 400 5.0 parts by weight Ion-exchanged water The remainder [0035]
A second embodiment will be described. An ink composition for ink jet recording of Example 2 was prepared by adding the following components.
Pigment dispersion 2 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight Nonionic surfactant 0.1 part by weight (manufactured by Air Products) Surfinol 104E)
Polyethylene glycol 400 5.0 parts by weight Ion-exchanged water The remainder [0036]
A third embodiment will be described.
An ink composition for ink jet recording of Example 3 was prepared by adding the following components.
CAB-O-JET300 33.3 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight Nonionic surfactant 0.1 parts by weight (Air Products Co., Ltd.) Manufactured by Surfinol 104E)
Polyethylene glycol 400 5.0 parts by weight Ion-exchanged water The remainder [0037]
Example 4 will be described. An ink composition for ink jet recording of Example 4 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight fluorinated surfactant 0.01 part by weight (manufactured by Asahi Glass Co., Ltd.) Surflon S-111)
The balance of ion-exchanged water [0038]
Example 5 will be described. An ink composition for inkjet recording of Example 5 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight fluorinated surfactant 0.03 parts by weight (manufactured by Asahi Glass Co., Ltd.) Surflon S-111)
The balance of ion-exchanged water [0039]
Example 6 will be described. An ink composition for inkjet recording of Example 6 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight acetylene glycol-based surfactant 0.1 part by weight (air products (Surfinol 104E)
The balance of ion-exchanged water [0040]
Example 7 will be described. An ink composition for ink jet recording of Example 7 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight polyethylene glycol 400 5.0 parts by weight acetylene glycol surfactant 0 .1 part by weight (Surfinol 440 manufactured by Air Products)
The balance of ion-exchanged water 【0041】
Reference Example 8 will be described. An ink composition for ink jet recording of Reference Example 8 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight Propylene glycol 4.0 parts by weight Polyethylene glycol 400 5.0 parts by weight Polyoxyalkylene ether surfactant 0.3 parts by weight ( Union Carbide Tergitol 15-S-30)
The balance of ion-exchanged water [0042]
Example 9 will be described. An ink composition for inkjet recording of Example 9 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight polyoxyalkylene ether surfactant 0.3 parts by weight ( Union Carbide Tergitol 15-S-20)
Ion exchange water balance [0043]
Comparative Example 1 will be described. An ink composition for inkjet recording of Comparative Example 1 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 8.0 parts by weight propylene glycol 6.0 parts by weight isopropyl alcohol 2.0 parts by weight polyethylene glycol 400 5.0 parts by weight Nonionic surfactant 0. 1 part by weight (Surfinol 104E manufactured by Air Products)
The remaining ion exchange water [0044]
Comparative example 2 will be described. An ink composition for inkjet recording of Comparative Example 2 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 10.0 parts by weight propylene glycol 6.0 parts by weight isopropyl alcohol 0.5 parts by weight polyethylene glycol 400 5.0 parts by weight Nonionic surfactant 0. 1 part by weight (Surfinol 104E manufactured by Air Products)
The remaining ion exchange water [0045]
Comparative Example 3 will be described. An ink composition for ink jet recording of Comparative Example 3 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyvinyl pyrrolidone 3.0 parts by weight Nonionic surfactant 0.1 part by weight (manufactured by Air Products) Surfinol 104E)
The remaining ion exchange water [0046]
Comparative example 4 will be described. An ink composition for ink jet recording of Comparative Example 4 was prepared by adding the following components.
Pigment dispersion 3 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight Nonionic surfactant 0.1 part by weight (manufactured by Air Products) Surfinol 104E)
Polyethylene glycol 400 5.0 parts by weight Ion-exchanged water The remainder [0047]
Comparative Example 5 will be described. An ink composition for ink jet recording of Comparative Example 5 was prepared by adding the following components.
Pigment dispersion 4 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight isopropyl alcohol 0.5 parts by weight Nonionic surfactant 0.1 part by weight (manufactured by Air Products) Surfinol 104E)
Polyethylene glycol 400 5.0 parts by weight Ion-exchanged water The remainder [0048]
Comparative Example 6 will be described. An ink composition for inkjet recording of Comparative Example 6 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight Fluorosurfactant 0.05 parts by weight (manufactured by Asahi Glass Co., Ltd.) Surflon S-111)
The balance of ion-exchanged water [0049]
Comparative Example 7 will be described. An ink composition for inkjet recording of Comparative Example 7 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight acetylene glycol surfactant 0.02 parts by weight (air product (Surfinol 104E)
The balance of ion-exchanged water [0050]
Comparative Example 8 will be described. An ink composition for ink jet recording of Comparative Example 8 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight Acetylene glycol surfactant 0.7 parts by weight (air product Surfynol 465 manufactured by the company)
The remaining ion exchange water [0051]
Comparative Example 9 will be described. An ink composition for inkjet recording of Comparative Example 9 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight polyoxyalkylene ether surfactant 0.2 parts by weight ( Union Carbide Tergitol 15-S-40)
The remaining ion-exchanged water [0052]
Comparative Example 10 will be described. An ink composition for inkjet recording of Comparative Example 10 was prepared by adding the following components.
Pigment dispersion 1 25.0 parts by weight N-methyl-2-pyrrolidone 6.0 parts by weight propylene glycol 4.0 parts by weight polyethylene glycol 400 5.0 parts by weight polyoxyalkylene ether surfactant 0.3 parts by weight ( Union Carbide Tergitol 15-S-15)
The balance of ion-exchanged water [0053]
The characteristics and evaluation of the ink compositions for inkjet recording of Examples 1 to 7, Reference Example 8, Example 9, and Comparative Examples 1 to 10 were performed as follows, and the results are shown in FIG. The characteristics were measured as follows.
(A) Measurement of dynamic contact angle The dynamic contact angle was measured by using DAT 1100 (manufactured by FIBRO system ab) and dropping 2 μl of ink onto a bright white paper (manufactured by Hewlett Packard). went.
(B) Measurement of surface tension The surface tension was measured at 25 ° C. using CBVP-A3 (manufactured by Kyowa Interface Science).
[0054]
Using each ink composition for ink jet recording obtained as described above, recording was performed on a Bright White Paper using a DeskJet 815C (manufactured by Hewlett Packard) ink jet printer.
(1) Measurement of print density A solid image of 2 cm x 2 cm was formed using each ink jet recording ink, and after standing for 2 hours, the optical density at the center of the solid image was measured using a spectrocolorimetric densitometer X-Rite 938 (Japan) Measured with a lithographic equipment) “○” when the density is 1.25 or more, “△” when the density is 1.15 or more and less than 1.25, “×”.
(2) Density uniformity A solid image of 2 cm x 2 cm was formed using each ink for ink jet recording, and after standing for 2 hours, the density uniformity of the solid image was visually evaluated. Those which can be judged to be uniform visually are indicated by “◯”, and those which have density unevenness in the solid image are indicated by “x”.
(3) Bleeding A solid image of 2 cm × 2 cm was formed using each ink for ink jet recording, and after standing for 2 hours, the edge portion of the solid image was visually evaluated using a 10 × magnifier. A sharp edge portion is indicated by “◯”, and a blurring portion is indicated by “×”.
(4) Ejection stability Ten solid images having a printing rate of 60% were continuously printed using each ink-jet recording ink composition, and banding and blurring of printing were evaluated visually. The case where no banding or fading occurred was indicated by “◯”, and the case where fading of banding or printing was observed was indicated by “X”.
[0055]
When the measurement and evaluation result of FIG. 1 is seen, the ink composition for inkjet recording of Examples 1-7 , Reference Example 8, and Example 9 is compared with Comparative Examples 1-10, printing density, uniformity, and blur. It can also be seen that the discharge stability is excellent. This Example 1-7, Reference Example 8, the inkjet recording ink composition of Example 9, a dynamic contact after 10 seconds when the Stockigt sizing degree is 2μl dropwise to 30 seconds on plain paper This is because the angle is 50.0 ° or more and the time change rate of the dynamic contact angle thereafter is 0.8 ° / second or less.
[0056]
【The invention's effect】
According to the present invention, it is possible to obtain an ink composition for ink jet recording containing a pigment having a high optical density when printed on plain paper, causing no density unevenness and blurring, and having excellent ejection stability.
[Brief description of the drawings]
FIG. 1 is a table for explaining the characteristics and evaluation of ink compositions for ink jet recording in Examples and Comparative Examples.

Claims (3)

At least a pigment, a water-soluble organic solvent, a surfactant and water,
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
c ) The nonionic surfactant is a fluorosurfactant, and the surface tension is 25 mN / m or more,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle Is 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. An ink composition for ink-jet recording, wherein a plurality of these are used in combination. At least a pigment, a water-soluble organic solvent, a surfactant and water,
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
d ) The nonionic surfactant is an acetylene glycol surfactant, and the surface tension is 35 to 45 mN / m,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle Is 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. An ink composition for ink-jet recording, wherein a plurality of these are used in combination. At least a pigment, a water-soluble organic solvent, a surfactant and water,
a ) a self-dispersing pigment in which the surface of the pigment is modified with a hydrophilic group;
b ) The surfactant is a nonionic surfactant,
e ) The nonionic surfactant is a polyoxyalkylene ether surfactant, and the surface tension is 30 to 50 mN / m ,
A dynamic contact angle after 10 seconds 50.0 ° ~71.1 ° when Stockigt sizing degree was 2μl dropped below the plain paper 30 seconds, and the time rate of change of the subsequent dynamic contact angle Is 0.17 ° / second to 0.8 ° / second, and the colorant used in the ink jet recording liquid is 0.5 to 10% by weight based on the weight of the ink jet recording liquid, and is a water-soluble organic solvent. An ink composition for ink-jet recording, wherein a plurality of these are used in combination.

Images