JPH0564665B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a recording ink, and more particularly to an inkjet recording ink suitable for an inkjet method in which recording is performed by ejecting droplets from an orifice of a recording head, and particularly to a magenta inkjet recording ink. . [Prior Art] Traditionally, writing instruments (signature pens, water-based ballpoint pens, etc.) for recording on recording materials such as paper have been made by dissolving or dispersing various dyes and pigments in water or other organic solvents as ink. are used. In addition, various dyes and pigments are used in the so-called inkjet recording method, in which ink in the head is ejected from minute nozzles using the pressure generated by the vibration and heat of a piezoelectric vibrator or the electrostatic attraction caused by the application of high voltage. Dissolved or dispersed in water or other organic solvents are used. However, compared to stationery inks such as general felt-tip pens and water-based ballpoint pens, the inject recording method generates ink droplets from an extremely small nozzle for recording, so the ink has many characteristics and is subject to stricter conditions. is required. That is, the ink used for inkjet recording must satisfy the following conditions. 1. It must have appropriate physical property values depending on the droplet generation method and droplet flight direction control method. 2. Stable for long-term storage, with no solid matter adhering to the vicinity of the nozzle. 3. The printed image must have sufficiently high contrast and clarity. 4. The printed image has excellent water resistance and light resistance. 5. Dry quickly after printing. etc. are listed as conditions. However, it is extremely difficult to satisfy all of these conditions, and conventional techniques have been unsatisfactory. In addition, dyes and pigments used for color recording using the four primary colors of cyan, magenta, yellow, and black are, for example, Japanese Patent Publication No. 52-13126, Japanese Patent Application Laid-open No. 49-1986.
No. 89534, JP-A-50-95008, JP-A-53-77706
No. 51-90624 and other publications. However, dye-type inks are generally insufficient in terms of water resistance and light resistance of recorded images. Although pigments have excellent water resistance and light resistance, they require a good dispersion medium for the particles, especially when applied to inkjet recording methods.
The pigment particles must not only be stably dispersed, but also be stable against rapid changes in the environment, which is not the case with conventional dispersion systems. Because such advanced technology is required, nothing that satisfies all requirements has yet been obtained. [Problems to be solved by the invention] 1. The first purpose of the present invention is to solve the problems for long-term storage.
To obtain a magenta ink for inkjet recording which has high dispersion stability and dissolution stability and is less likely to cause clogging in nozzles. 2 A second object of the present invention is to obtain a magenta ink for inkjet recording that provides images with excellent water resistance, light resistance, etc. 3. A third object of the present invention is to obtain a magenta ink for inkjet recording that provides images with high optical density and clear color tone. [Means for Solving the Problems] That is, the present invention provides a red pigment and a compound having the following structural formula ().
A water-soluble red dye represented by, a polymer dispersant,
The gist of the present invention is a recording ink containing at least a surfactant having a polyoxyethylene group with an HLB of 11 or more and an aqueous medium. Structural formula() (

[Effect]

The recording ink of the present invention has excellent permeability to recording materials and dries in a short time, making it suitable for high-speed recording, and the recorded image has a high optical density and a clear magenta color tone. Furthermore, the image has excellent water resistance and light resistance. Furthermore, the inks of the present invention exhibit many excellent properties. That is, although the reason is not clear, by using the polymeric dispersant and surfactant used in the present invention in combination, the dispersion stability of the pigment is significantly improved compared to when each is used alone. When the red dye represented by the structural formula () used in the invention is used in combination with the pigment used in the invention, a synergistic effect is seen in that water resistance and light resistance are improved compared to when used alone. . In this way, the ink of the present invention not only has excellent ejection stability, ejection response, droplet uniformity, and continuous recording performance, but also has excellent image quality, storage stability, maintainability of equipment, and selection of constituent components. It also exhibits excellent properties in terms of degrees of freedom. [Structure of the Invention] Each component of the present invention will be explained below. Red pigments are used as colorants, and those used in the present invention are CIPigment Red 5, 11,
12, 13, 14, 16, 23, 26, 29, 31, 32, 34, 39,
40, 49, 54, 56, 57, 58, 61, 62, 67, 73, 74,
75, 78, 80, 84, 87, 114, 122, 133, 142, 147,
154, 155, 156, 157, 159, 165, 170, 175, 176,
183, 184, 185, 187, 192, 193, 196, 199, 200,
CIVat Red 1, 2, 3, 10, 11, 12, 13, 16,
At least one of 19, 24, 30, 31, 34, 38, 41, 49. A water-soluble red dye is also used as a coloring material, and the dye used in the present invention is represented by the above structural formula (). The usage ratio of the above red pigment and water-soluble red dye is 1 part water-soluble red dye per 100% by weight of red pigment.
It is preferable to use it in the range of ~50% by weight. or,
The total amount of the colorant, which is a combination of red pigment and water-soluble red dye, is determined as desired, but is usually 0.1 to 20% by weight, preferably 0.5 to 15% by weight, based on the total amount of ink. Preferably it is 1 to 10% by weight. If it is less than 1% by weight, the print density will be low and difficult to see, making it impractical; if it is more than 10% by weight, the solid content concentration in the ink will become too high, and the ink will dry easily at the nozzle, causing problems such as scratches. . Polymer dispersants have the ability to improve dispersion stability through effects such as reducing interfacial free energy through adsorption onto the pigment surface, and steric hindrance protection through the formation of adsorption and solvation layers on the polymer itself. There is no particular limitation if it is, and specifically proteins such as gelatin, albumin, casein, etc.
Natural rubbers such as gum arabic and gum tragacanth,
Glucosides such as saponin, methylcellulose,
Cellulose derivatives such as carboxymethylcellulose and hydroxymethylcellulose, lignin sulfonates, natural polymers such as shellac, polyacrylates, amine salts of styrene-acrylic acid copolymers, amine salts of vinylnaphthalene-acrylic acid copolymers, Anionic polymers such as styrene-maleic acid copolymer, amine salt of vinylnaphthalene-maleic acid copolymer, sodium salt of formalin condensate of β-naphthalenesulfonic acid, phosphate, polyvinyl alcohol, Examples include synthetic polymers such as non-ionic polymers such as polyvinylpyrrolidone and polyethylene glycol, and these can be used alone or in combination, and the amount used is 0.01 to 15% by weight based on the total amount of ink. preferable. Surfactants are used to improve wetting of the surface of hydrophobic pigments due to their strong penetrating power, and to stabilize the dispersion of pigments in aqueous systems.
When used in combination with the above-mentioned polymeric dispersant, the effect is further exhibited, and the one used in the present invention is
At least one of the activator group consisting of polyoxyethylene alkyl ether with HLB of 11 or higher, polyoxyethylene polyoxypropylene alkyl ether with HLB of 11 or higher, and polyoxyethylene alkyl ether sulfate, and specific examples thereof are listed below. NITSUKOL BL-4.2 is a polyoxyethylene alkyl ether with an HLB of 11 or higher.
(HLB: 11.5), same BL-9EX (HLB: 14.5), same
BL-21 (HLB: 19.0), BL-25 (HLB: 19.5)
(all manufactured by Nikko Chemicals Co., Ltd.), Pegnol L-6
(HLB: 11.7), L-12 (HLB: 14.8) (above,
Toho Chemical Industry Co., Ltd.), Emulgen 108 (HLB:
12.1), 109-P (HLB: 13.8), 120 (HLB:
15.3), 147 (HLB: 17.1) (manufactured by Kao Atlas Co., Ltd.), Emulsin L-90-S (HLB: 13.6),
Same L-230 (HLB: 16.9), Same L-380 (HLB:
17.7) (manufactured by Sanyo Chemical Industries, Ltd.) and other polyoxyethylene lauryl ethers, and Nitsukor BC.
-7 (HLB: 11.5), BC-10TX (HLB: 13.5),
BC-15TX (HLB: 15.5), BC-20TX
(HLB: 17.0), BC-23 (HLB: 18.0), BC
-25TX (HLB: 18.5), BC-30TX (HLB:
19.5), BC-40TX (HLB: 20.0) (manufactured by Nikko Chemicals Co., Ltd.), Pegnol C-14 (HLB:
14.4), polyoxyethylene cetyl ether such as C-18 (HLB: 15.3) (manufactured by Toho Chemical Industry Co., Ltd.), Emulgen 220 (HLB: 14.2) (manufactured by Kao Atlas Co., Ltd.), and Nitsukol BS. -20 (HLB: 18.0) (manufactured by Nikko Chemicals Co., Ltd.), Pegnol 14-S (HLB:
11.5) (manufactured by Toho Chemical Industry Co., Ltd.), Emulgen 320
Polyoxyethylene stearyl ether such as (HLB: 13.9) (manufactured by Kao Atlas Co., Ltd.) and Nitsukol
BO-10TX (HLB: 14.0), BO-15TX
(HLB:16.0), same BO-20 (HLB:17.0), same BO
-50 (HLB: 18.0) (Nikko Chemicals Co., Ltd.)
), Pegnol O-20 (HLB: 15.3) (manufactured by Toho Chemical Industry Co., Ltd.), Emulgen 409P (HLB: 12.1),
420 (HLB: 13.6), 430 (HLB: 16.2) (or higher,
Polyoxyethylene oleyl ether (manufactured by Kao Atlas Co., Ltd.), Nitsukor BB-20 (HLB:
16.5), polyoxyethylene behenyl ether such as BB-30 (HLB: 18.0) (manufactured by Nikko Chemicals Co., Ltd.), and Nikkor BEG-1630 (HLB: 15.5)
Polyoxyethylene hexyldecyl ether (manufactured by Nikko Chemicals Co., Ltd.), Nitsukol BEG-
Examples include polyoxyethylene decyl tetradecyl ether such as 2430 (HLB: 15.5) (manufactured by Nikko Chemicals Co., Ltd.). In addition, as polyoxyethylene polyoxypropyrealkyl ethers with HLB of 11 or higher, Nitsukol PBC-34 (HLB: 16.5) and Nitsukol PBC-44 (HLB:
12.5) (manufactured by Nikko Chemicals Co., Ltd.), polyoxyethylene polyoxypropylene cetyl ether, Nikkor PEN-4620 (HLB: 11.0), etc.
Examples include polyoxyethylene polyoxypropylene decyl tetradecyl ether such as PEN-4630 (HLB: 12.0) (manufactured by Nikko Chemicals Co., Ltd.). In addition, as the polyoxyethylene alkyl ether sulfate, Nikkor SBL-4N, Nikkol SBL-
4T, NES-203, NES-303, SNP-4N
(manufactured by Nikko Chemicals Co., Ltd.), Emar 20C,
NC (manufactured by Kao Atlas Co., Ltd.), etc. The above-mentioned activators can be used alone or in combination, and the amount used is based on the total amount of ink.
0.01-10% by weight is preferred. As the aqueous medium, water alone or a mixture of water and a water-soluble organic solvent can be used. Specific examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, ethylene glycol monomethyl ether, and ethylene glycol. Glycols and their derivatives such as glycol monoethyl ether, ethylene glycol monobutyl ether, glycerin,
Monoethanolamine, diethanolamine, isopropanolamine, N-methyldiethanolamine, NN-dimethylethanolamine, 2
N-alkanolamines such as -(2-aminoethylamino)ethanol, alcohols such as 2-chloroethanol and tetrahydrofurfuryl alcohol, acetamide, formamide,
There are amides such as N-methylacetamide, N-methylformamide, N-methylpropylamide, and NN-dimethylamide, as well as sulfolane, 2-pyrrolidone, and N-methyl-2-pyrrolidone, which can be used alone or in combination. The amount used is preferably 1 to 50% by weight based on the total amount of the ink. Also, the amount of water used is 30% of the total amount of ink.
~80% by weight is preferred. In addition to the above ingredients, if necessary, urea and/or its derivatives may be used as auxiliary agents for moisturizing agents, formalin, phenol, pentachlorophenol sodium, dehydrochloride, etc. to prevent ink flow inhibition due to mold growth and ink decay. sodium acetate,
A small amount of an antiseptic and fungicidal agent such as 1,2-benzisothiazolin-3-one may be added as appropriate. Furthermore, when the ink comes into contact with metal parts, benzotriazole may be added as necessary to prevent metal corrosion. Corrosion and rust preventive agents such as ethylenediaminetetraacetate and the like can also be added as appropriate. Although the ink of the present invention, which has the above-mentioned components as its basic constituents, has excellent properties in itself, various additives may be added in order to provide even more remarkable recording properties. Various methods can be adopted as a method for manufacturing the recording ink of the present invention, and one example is as follows.
It is obtained by blending the above-mentioned components and mixing and grinding the mixture using a conventionally known dispersing machine such as a ball mill, homomixer, sand grinder, speed line mill, or roll mill. [Example] The present invention will be explained in more detail based on the following examples, where "parts" in the examples indicate "parts by weight." Example 1 CIPigment Red 5 5.0 parts Red dye represented by the structural formula () (n=2)
0.5 parts styrene-maleic acid copolymer amine salt
4.5 parts Nitskol BL-21 (manufactured by Nikko Chemicals Co., Ltd.)
1.0 parts urea 9.0 parts glycerin 13.0 parts ethylene glycol monobutyl ether
1.0 part ethylene glycol 1.2 parts Proxel XL-2 (preservative and fungicide, 1,2-benzisothiazolin-3-one, manufactured by ICI Japan Co., Ltd.) 0.2 parts ion-exchanged water 64.6 parts Disperse each of the above ingredients using a ball mill. The resulting dispersion was centrifuged, and coarse particles were removed using a filter to obtain magenta ink. Example 2 CIPigment Red 11 5.0 parts Red dye represented by the structural formula () (n=2)
0.5 parts styrene-maleic acid copolymer amine salt
4.5 parts Nitsukol PBC-34 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 64.6 parts Example 3 CIPigment Red 61 5.0 parts Shown by structural formula () red dye (n=2)
0.5 parts styrene-maleic acid copolymer amine salt
4.5 parts Nitsukol PBC-34 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether
1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 64.6 parts Example 4 CIPigment Red 114 5.0 parts Red dye represented by the structural formula () (n=2)
0.5 parts styrene-acrylic acid copolymer amine salt
4.0 parts Nitsukol BL-21 1.0 parts urea 9.0 parts glycerin 13.0 parts ethylene glycol monobutyl ether
1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 65.1 parts Example 5 CIPigment Red 155 5.0 parts Red dye represented by the structural formula () (n=2)
0.5 parts Polyvinyl alcohol 2.5 parts Emal 20C 1.2 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether
1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 66.4 parts Example 6 CIPigment Red 157 5.0 parts Red dye represented by the structural formula () (n=2)
0.5 parts Polyvinyl alcohol 2.5 parts Emal 20C 1.2 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 66.4 parts Example 7 CIPigment Red 170 5.0 parts Structural formula () Red dye represented by (n=2)
0.5 parts Polyvinylpyrrolidone 5.0 parts Emulgen 147 0.9 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 64.2 parts Example 8 CIPigment Red 192 5.0 parts Structural formula () Red dye represented by (n=2)
0.5 parts styrene-acrylic acid copolymer amine salt
4.0 parts Nitsukol BL-21 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 65.1 parts Example 9 CIPigment Red 200 5.0 parts Shown by structural formula () red dye (n=2)
0.5 parts Polyvinylpyrrolidone 5.0 parts Emulgen 147 0.9 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 64.2 parts Example 10 CIVat Red 1 5.0 parts Structural formula () Red dye represented by (n=2)
0.5 parts styrene-acrylic acid copolymer amine salt
4.0 parts Nitsukol NBS-203 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 65.1 parts Example 11 CIVat Red 30 5.0 parts Shown by structural formula () red dye (n=2)
0.5 parts Carboxymethyl cellulose 4.0 parts Nitsukol NBS-203 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 65.1 parts Comparative example 1 Shown by structural formula () Red dye (n=2)
5.5 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 70.1 parts Comparative example 2 CIPigment Red 5 5.5 parts Amine salt of styrene-maleic acid copolymer
4.5 parts Nitsukol BL-21 1.0 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion exchange water 64.6 parts Comparative example 3 CIPigment Red 5 5.0 parts Shown by structural formula () red dye (n=2)
0.5 parts styrene-maleic acid copolymer amine salt
4.5 parts Urea 9.0 parts Glycerin 13.0 parts Ethylene glycol monobutyl ether 1.0 parts Ethylene glycol 1.2 parts Proxel XL-2 0.2 parts Ion-exchange water 65.6 parts A magenta ink was obtained in the same manner. (Effects of the Invention) As described above, _T1 was studied using the inks of Examples 1 to 11 and Comparative Examples 1 to 3, and an on-demand recording head (discharge orifice diameter 5 μm) that discharges ink using a piezo vibrator T ₂ to T ₆ were investigated using a recording device having the following. (T ₁ ) Storage stability of ink: The ink was sealed in a glass container and stored at -5°C and 50°C for one year, and changes were examined. (T ₂ ) Ejection stability: Continuous ejection was performed in an atmosphere at a room temperature of 5° C. and 40° C. to examine recording stability. (T ₃ ) Color tone and density of recorded images: Test pieces were printed on inkjet paper (ST-704A, manufactured by Jujo Paper Co., Ltd.) and visually evaluated. (T ₄ ) Water resistance of recorded images: The test piece used for color tone evaluation was immersed in water for 1 hour, air-dried indoors, and visually evaluated. (T ₅ ) Light resistance of recorded images: The test piece used for color tone evaluation was irradiated for 3 hours with a fade-o-meter, and the color difference from before irradiation was measured. (T ₆ ) Drying properties of recorded images: After printing on the above inkjet paper, paper (Toyo Paper, No. 5C)
The paper was rubbed several times and evaluated based on the presence or absence of color transfer to the paper. In all of the inks obtained in Examples 1 to 11, no precipitation of insoluble matter or change in ink physical properties or color tone was observed even after long-term storage, and stable ejection was possible during actual printing. Furthermore, the recorded images had excellent water resistance and light resistance, were bright in color, had high density, and had good drying properties after printing. Similar studies were conducted on the inks obtained in Comparative Examples 1 to 3. In all cases, the inks were inferior to the inks of Examples in terms of long-term storage stability, density, and sharpness of recorded images. As described above, the recording ink of the present invention not only has excellent ejection stability, ejection response, and storage stability, but also
The recorded images are excellent in color tone, density, water resistance, light resistance, and print drying properties, making them ideal as jet recording inks. The recording ink of the present invention is also suitable for other recording methods such as wire dot printers other than inkjet recording.

Claims (1)

[Scope of Claims] 1. A red pigment, a water-soluble red dye represented by the following structural formula (), a polymer dispersant, a surfactant having a polyoxyethylene group with an HLB of 11 or more, and an aqueous medium. Recording ink containing at least Structural formula() ([Formula] R ₁ : aliphatic hydrocarbon having 18 carbon atoms n = 2 or 3) 2 The red pigment is CIPigment Red 5, 11,
12, 13, 14, 16, 23, 26, 29, 31, 32, 34, 39,
40, 49, 54, 56, 57, 58, 61, 62, 67, 73, 74,
75, 78, 80, 84, 87, 114, 122, 133, 142, 147,
154, 155, 156, 157, 159, 165, 170, 175, 176,
183, 184, 185, 187, 192, 193, 196, 199, 200,
CIVat Red 1, 2, 3, 10, 11, 12, 13, 16,
19, 24, 30, 31, 34, 38, 41, and 49. 3 Claims in which the surfactant having a polyoxyethylene group with an HLB of 11 or more is at least one of polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, and polyoxyethylene alkyl ether sulfate. The recording ink described in item 1.