JP3223550B2 - Aqueous ink composition for inkjet recording - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink composition for ink-jet recording, and more particularly, to an ink-jet ink composition which imparts conductivity without impairing the dissolution stability of a dye and has an excellent drying prevention effect. The present invention relates to a recording aqueous ink composition.

[0002]

2. Description of the Related Art Generally, aqueous inks using water as a main solvent and oil-based inks using an organic solvent as a main solvent are used as inks for ink jet recording. Printed images using water-based inks are generally poor in water resistance, but are excellent in safety because the main solvent is water, and can provide printed images of excellent quality. It has become mainstream.

On the other hand, the disadvantages of the ink jet recording system are as follows.
Clogging of nozzles, changes in ink properties (eg, viscosity, electrical conductivity) over time, and the likelihood of abnormal ink ejection due to various other factors are the biggest factors preventing the spread of inkjet recording. Has become.

[0004] As an ink jet recording system, a so-called electric field control system in which ink is ejected using electrostatic attraction; a so-called drop-on-demand system (pressure pulse) in which ink is ejected using vibration pressure of a piezo element. Method); ink is ejected using pressure generated by forming and growing bubbles by high heat, a so-called bubble jet method; pressure is applied by a pump after a nozzle, and at the same time high frequency vibration is applied by a piezo element. Charge control method (continuous method) in which ink is charged with a charging electrode to the ink droplets and the ink droplets charged with the control electrode are further controlled (continuous method); a spark is generated in the ink under a high voltage applied state Various types of ink jets, such as the so-called spark jet method, which ejects ink with its explosive power DOO recording method has been proposed, these methods, it is possible to obtain an image of extremely high definition.

[0005] Among these ink jet recording systems,
Ink used in the so-called charge control method, which controls ink particles by an electric field, and in the so-called spark jet method, in which an electric current is applied to the ink and the ink is ejected using the heat generation / boiling phenomenon, etc. Conductivity must be controlled within an appropriate range. In other ink jet systems, control of the conductivity may be required to detect the remaining amount of ink.

Conventionally, a dye has been used as a coloring agent for aqueous inks, and since the dye itself is an electrolyte, it exhibits a certain degree of conductivity due to ionization. However, in a charge control method, a spark jet method, or the like, conductivity by a dye alone is not sufficient, and it is necessary to impart higher conductivity. In addition, in the case of an ink using a pigment as a coloring agent, conductivity due to the pigment itself is hardly obtained.

When conductivity is required, the addition of a conductivity-imparting agent has been proposed. Examples of the conductivity-imparting agent include inorganic salts such as lithium chloride, ammonium chloride and sodium chloride (Japanese Patent Publication No. 2-5785). Is known.

[0008]

However, the addition of such inorganic salts often impairs the dissolution stability of the dye, so that the amount of addition is limited and the desired conductivity may not be obtained. . Further, the aqueous ink containing inorganic salts and the like,
Dyes and inorganic salts precipitated due to evaporation of water, and the nozzles were easily clogged. SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous ink composition for ink-jet recording that can obtain desired conductivity without impairing the dissolution stability of the ink and without causing nozzle clogging.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, the present invention relates to an aqueous ink composition for ink-jet recording containing water and a colorant, wherein an alkanolamine or an ethylene oxide and / or propylene oxide adduct thereof and a salt comprising hydrogen halide are used as a conductivity-imparting agent. The present invention relates to an aqueous ink composition for inkjet recording characterized by containing

Further, the present invention relates to an aqueous ink composition for ink-jet recording, which contains diethanolamine as an alkanolamine and diethanolamine hydrochloride as a hydrogen halide as hydrochloric acid having excellent conductivity-imparting effects.

The addition of ethylene oxide and / or propylene oxide to the alkanolamine is effective in increasing the hygroscopicity of the ink, and the addition of propylene oxide is effective in suppressing the bubbling of the ink. Triethanolamine and diethanolamine are also ethylene oxide adducts to ethanolamine. The preferred number of moles of these ethylene oxide and propylene oxide is not particularly limited, but from the viewpoint of the ability to impart conductivity and the solubility,
More preferably, it is 12 mol or less for ethylene oxide and 3 mol or less for propylene oxide.

Specifically, there are the following compound examples. Compound Examples Compound 1 Diethanolamine hydrochloride Compound 2 Diethanolamine hydrofluoride Compound 3 Diethanolamine hydrobromide Compound 4 Diethanolamine hydroiodide hydrochloride Compound 5 Triethanolamine hydrochloride Compound 6 Ethanolamine hydrobromide Compound 7 N -Methyldiethanolamine hydrochloride Compound 8 Hydrofluoric acid of ethylene oxide 2 mol adduct of N-methyldiethanolamine Compound 9 Hydrochloride of ethylene oxide 3 mol of triethanolamine and 2 mol of propylene oxide adduct The alkanolamine of the present invention described above The conductivity-imparting agent comprising a salt of hydrogen halide and a salt other than those described above can be used in combination other than the above. Salts can be easily formed even if they are separately compounded in the ink. But not
A range of 0.01 to 30% by weight is more preferable. The ratio is alkaline when the alkanolamine is equal to or greater than an equivalent, and acidic when the alkanolamine is equal to or less than the equivalent, so that the pH may be set to an arbitrary value according to the dissolution stability of the colorant. It may be neutralized and set to an arbitrary pH with a pH adjuster such as another organic acid or inorganic acid. Also, a plurality of alkanolamines and hydrogen halides may be used in combination.

The amount of the conductivity-imparting agent used in the present invention cannot be specified unconditionally depending on the desired value of the electric conductivity and the kind of the coloring agent to be combined, but it is 0.01 to 30% by weight in the ink composition. A range is preferred.

As the colorant, a water-soluble dye is preferable.
Any water-soluble one can be used, and it can be selected from acid dyes, basic dyes, direct dyes, reactive dyes, disperse dyes, food dyes, fluorescent brighteners and the like.

Examples of the acid dye include C.I. I. Acid Black 1, 2, 7, 16, 17, 24, 26,
28, 31, 41, 48, 52, 58, 60, 63, 9
4,107,109,112,118,119,12
1,122,131,155,156; C.I. I. Acid Yellow 1,3,4,7,11,12,13,1
4,17,18,19,23,25,29,34,3
6,38,40,41,42,44,49,53,5
5,59,61,71,72,76,78,79,9
9,111,114,116,122,135,14
2,161,172; C.I. I. Acid Orange 7,
8, 10, 19, 20, 24, 28, 33, 41, 4
5, 51, 56, 64; I. Acid Red 1,
4,6,8,13,14,15,18,19,21,2
6,27,30,32,34,35,37,40,4
2,51,52,54,57,80,82,83,8
5,87,88,89,92,94,97,106,1
08, 110, 111, 114, 115, 119, 12
9,131,133,134,135,143,14
4,152,154,155,172,176,18
0,184,186,187,249,254,25
6,289,317,318; C.I. I. Acid Violet 7, 11, 15, 34, 35, 41, 43, 4
9, 51, 75; I. Acid Blue 1,7,
9, 15, 22, 23, 25, 27, 29, 40, 4
1,43,45,49,51,53,55,56,5
9,62,78,80,81,83,90,92,9
3,102,104,111,113,117,12
0, 124, 126, 138, 145, 167, 17
1,175,183,229,234,236,24
9; I. Acid Green 3,9,12,16,1
9, 20, 25, 27, 41, 44; I. Acid Brown 4, 14 and the like.

Examples of the basic dye include C.I. I. Basic black 2, 8; I. Basic yellow 1, 2, 11, 12, 14, 21, 32, 36;
I. Basic orange 2,15,21,22; C.I.
I. Basic Red 1,2,9,12,13,3
7; I. Basic Violet 1,3,7,1
0, 14; I. Basic Blue 1,3,5
7, 9, 24, 25, 26, 28, 29; I. Basic green 1, 4; I. Basic Brown 1, 12 and the like.

Examples of the direct dye include C.I. I. Direct Black 2,4,9,11,14,17,1
9, 22, 27, 32, 36, 38, 41, 48, 4
9,51,56,62,71,74,75,77,7
8, 80, 105, 106, 107, 108, 112,
113, 117, 132, 146, 154, 168, 1
71, 194; I. Direct yellow 1,2,
4, 8, 11, 12, 24, 26, 27, 28, 33,
34, 39, 41, 42, 44, 48, 502, 51,
58, 72, 85, 86, 87, 88, 98, 100,
110, 127, 135, 141, 142, 144;
C. I. Direct orange 6,8,10,26,2
9, 41, 49, 51, 102; I. direct
Red 1, 2, 4, 8, 9, 11, 13, 152, 1
7, 20, 23, 24, 28, 31, 33, 37, 3
9,44,46,47,48,51,59,62,6
3,73,75,77,80,81,83,84,8
5,87,89,90,94,95,99,101,1
08,110,145,189,197,220,22
4,2252,226,227,230,250,25
4,256,257; C.I. I. Direct violet 1,7,9,12,35,48,51,90,94;
C. I. Direct Blue 1,2,6,8,15,2
2,25,34,69,70,71,72,75,7
6,78,80,81,82,83,86,90,9
8, 106, 108, 110, 120, 123, 15
8,163,165,192,193,194,19
5,196,199,200,201,202,20
3,207,218,236,237,239,24
6,258,287; C.I. I. Direct green 1, 6, 8, 28, 33, 37, 63, 64; I.
Direct Brown 1A, 2, 6, 25, 27, 4
4,58,95,100,101,106,112,1
73, 194, 195, 209, 210, 211 and the like.

As the reactive dye, for example, C.I. I. Reactive Black 1,3,5,6,8,12,1
4; I. Reactive Yellow 1,2,3,1
3, 14, 15, 17; I. Reactive orange 2,5,7,16,20,24; C.I. I. Reactive Red 6,7,11,12,15,17,21,2
3,24,35,36,42,63,66,84,18
4; I. Reactive Violet 2,4,5
8, 9; I. Reactive Blue 2,5,7,1
2,13,14,15,17,18,19,20,2
1, 25, 27, 28, 37, 38, 40, 41;
I. Reactive green 5, 7; I. Reactive Brown 1, 7, 16 and the like.

Food colors include, for example, C.I. I. Food black 1, 2; I. Food yellow 2,
4,5; C.I. I. Food Red 2,3,7,9,1
4,52,87,92,94,102,104,10
5,106; I. Food Violet 2: C.I.
I. Food blue 1, 2; I. Food Green 2, 3 and the like.

Other water-soluble dyes include, for example, "Kayaset Black Nine A", "Direct Deep Black XA" and "Direct Special Black AXN" manufactured by Nippon Kayaku Co., Ltd .; Special Black SP Liquid "," Biscript "
"Black SP Liquid", "Rebasel Turquoise Blue KS-6GLL", "Pyramine";"JI.BK-2","JI.BK-3" manufactured by Sumitomo Chemical Co., Ltd .; "JP-K81L" manufactured by Orient Chemical Co., Ltd. "," JP-K127
L "," JPK-139 "; I. Florescent
Brightening Agent 14, 22, 24, 3
2,84,85,86,87,90,134,166,
167, 169, 175, 176, 177 and the like. These colorants are not limited to the above.

When the electric conductivity is to be extremely increased, it is preferable to select a dye having excellent dissolution stability of the dye itself such as an acid dye among the above dyes. Pigments can also be used as the colorant, and can be selected from inorganic pigments, organic pigments, and the like. However, from the viewpoint of dispersion stability, the use of the electric conductivity imparting agent of the present invention in a small amount is preferred. .

These coloring agents can be used alone or in combination of two or more. The amount used in the ink composition is 0.1 to 10%.
A range of weight percent is desirable. Water-soluble organic solvents are used to prevent solidification of the ink due to evaporation of water at low humidity, to ensure resolubility in water and ink even after solidification, and to reduce the time for ink to penetrate plain paper. Can be done. Specifically, glycols such as ethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; glycol ethers such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and ethylene glycol monophenyl ether;
Pyrrolidones such as N-methyl-2-pyrrolidone; alkanolamines such as triethanolamine; alcohols such as methanol, ethanol and isopropyl alcohol; dimethyl sulfoxide; and the like, but are not limited thereto.

These water-soluble organic solvents may be used singly or in combination of two or more in consideration of the solvent's hygroscopicity and moisture retention, dye solubility, pigment dispersibility, ink viscosity and penetration time into plain paper. When used, the amount used in the ink composition is preferably in the range of 0.1 to 90% by weight.

As the water, it is preferable to use water having a purity higher than that of ion-exchanged water in order to stabilize the dissolution of the dye and prevent clogging of the nozzle due to heavy metal ions. The amount used in the ink composition is preferably in the range of 10 to 95% by weight.

Examples of the auxiliary agent include hydroxides of alkali metals, pH adjusters such as alkanolamines, antibacterial and antifungal agents, sequestering agents, pigment dispersants, surfactants, water-soluble polymers, and water-soluble polymers. You may use a conductive resin etc.

[0027]

The present invention will be described below with reference to examples. In the examples, "%" represents "% by weight".

Example 1 Compound 1 12% C.I. I. Food black 2 2% Diethylene glycol 5% Deionized water 81% After mixing the above components and dissolving them at room temperature,
Filtration was performed with a 0.45 micron membrane filter to obtain an aqueous ink for inkjet recording. 2 at this time
The viscosity of the ink at 5 ° C. is 1.5 cp, and the electric conductivity is 49.
mS / cm.

As a result of performing a printing jet test using an ink jet printer of a spark jet system, the printing quality was good, and no clogging of the nozzle occurred even after standing for 24 hours. Further, the ink was stored in an environment at 60 ° C. for one month, but there was no precipitate and the dissolution of the ink was stable.

Example 2 Compound 8 1% C.I. I. Direct Blue 199 2% Diethylene glycol 13% Ion-exchange water 84%
The solution was filtered through a 0.45 micron membrane filter to obtain an aqueous ink for inkjet recording. 2 at this time
The ink viscosity at 5 ° C. is 1.6 cp and the electric conductivity is 5 m
S / cm.

As a result of performing a printing test using a charge control type ink jet printer, the printing quality was good.
No nozzle clogging occurred even after standing for 24 hours.
Further, the ink was stored in an environment at 60 ° C. for one month, but there was no precipitate and the dissolution of the ink was stable.

COMPARATIVE EXAMPLE 1 Sodium chloride 12% C.I. I. Food black 2 2% Diethylene glycol 5% Ion-exchanged water 81% The above components were mixed, but partially dissolved, but dye agglomeration occurred, and the 0.45 micron membrane filter was often clogged, and ink could not be formed. .

Comparative Example 2 C.I. I. Direct Blue 199 2% Diethylene glycol 13% Ion-exchanged water 85% The above respective components except for the compound 8 from the composition of Example 2 were mixed, sufficiently dissolved at room temperature, and then filtered through a 0.45 micron membrane filter. Was carried out to obtain an aqueous ink for inkjet recording. At this time, the viscosity of the ink at 25 ° C. was 1.5 cp, and the electric conductivity was 1 mS / cm.

As a result of performing a printing test using an ink jet printer of a charge control system, the printing quality was not good due to insufficient control of the ink. However, nozzle clogging did not occur even after standing for 24 hours. In addition, 6
The ink was stored in an environment of 0 ° C. for one month, and there was no precipitate, and the dissolution of the ink was stable.

[0035]

According to the present invention, an ink composition having desired conductivity can be obtained by adding an electric conductivity imparting agent comprising the compound of the present invention, and an ink composition having an excellent drying prevention effect and excellent ink dissolution stability can be obtained. You can get things.

Claims (4)

(57) [Claims] An aqueous ink composition for ink jet recording containing water and a water-soluble dye, characterized in that it contains an alkanolamine or an ethylene oxide adduct and / or a propylene oxide adduct thereof, and a salt composed of hydrogen halide. Aqueous ink composition for inkjet recording. 2. The method according to claim 1, wherein the alkanolamine is diethanolamido.
Diethanolamide with hydrochloric acid as the hydrogen halide
The ink according to claim 1, further comprising:
Water-based ink composition for jet recording. 3. Alkanolamine or ethylene thereof
Oxide adduct and / or propylene oxide adduct
And a salt comprising hydrogen halide as a conductivity-imparting agent.
3. The method according to claim 1, wherein
Water-based ink composition for inkjet recording. 4. The aqueous inkjet recording ink composition, and a charge control method, according to claim 1, characterized in that is used for an ink jet printer of any type of spark jet type, either 2,3 A water-based ink composition for inkjet recording according to any one of the above.