JP2003246954A - Ink for ink-jet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain ink for ink-jet recording, which has excellent prevention of nozzle clogging, excellent dispersion stability, provides stable discharge even during continuous operation for many hours and after a stop for many hours and excellent redispersibility while keeping performances such as storage stability, high-quality recorded image, etc. <P>SOLUTION: The ink for ink-jet recording is obtained by atomizing a mixture comprising 20 parts of a red disperse dye technical product (C.I. Disperse Red 60), 12 parts of dispersant Na salt of β-naphthalenesulfonic acid formalin condensate, 5 parts of a compound represented by chemical formula (I) R-O-(CH<SB>2</SB>CH<SB>2</SB>O)<SB>n</SB>-H (R is a 31-32C straight-chain alkyl group; n is about 40; HLB is 16) and 123 parts of water by a sand mill by wet grinding to give a dispersion, mixing the dispersion with 5 parts of the compound (I), 120 parts of glycerol and 2.0 parts of a polyether-modified polydimethylsiloxane ('BYK-348' (R) made by BYK-Chemie/Japan (KK)) as a surface adjuster and water and adjusting a dye concentration to 5%. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inkjet recording ink in an inkjet recording system. More specifically, the present invention relates to an inkjet recording ink that uses a water-insoluble coloring material used in a piezo type inkjet method as a coloring material component, which is excellent in preventing clogging of nozzles of a recording head and in storage stability of the ink.

[0002]

2. Description of the Related Art A water-based ink jet recording ink is
It is generally in the form of a solution of a water-soluble dye or a water-insoluble coloring material dispersed in water or an aqueous solution containing a water-soluble organic solvent, but when water resistance is required or hydrophobic fiber is used. Inkjet printing using a water-insoluble dye when dyeing with water-soluble dye, or when dyeing by sublimation transfer to hydrophobic fiber or resin film products after inkjet printing on a medium such as paper Ink is being used.

Items required for the performance of ink jet recording inks using these water-insoluble coloring materials are:
(1) Prevention of nozzle clogging, ejection stability, (2) ink storage stability, (3) high-quality recorded image in which ink ejection directionality, ejection amount and dot shape are constant, (4)
Ink dryness, fixability (5) high print density, and the like are included.

In the ink jet recording system, since it is necessary to eject the ink as a small droplet of the ink from a thin nozzle, the above item (1) is particularly important. Particularly, in the on-demand type system, since the ejection of ink from the nozzle is temporarily stopped even during continuous operation, there is a problem that ejection failure occurs during continuous operation for a long time.

Further, in the case of a water-insoluble coloring material, unlike the case where a water-soluble dye is used, clogging occurs due to the formation of precipitates (aggregates) due to deterioration of dispersion stability, evaporation of the solvent in the nozzle, etc. Easy to cause. In particular, when the operation of the apparatus is left for a long time, clogging due to evaporation of the solvent is likely to occur.

Therefore, in order to suppress the evaporation of the solvent, a low-volatile solvent or a moisturizer is added, and even if a part of the solvent is lost due to the evaporation, the ink newly supplied from the ink reservoir can be re-dispersed. To this end, a hydrotrope agent has been added. The moisturizers include glycols such as glycerin and polyethylene glycol, and the hydrotropes include urea and ureas.

However, in the case of using these additives, the effect cannot be obtained by adding a small amount, and when used in a large amount, the viscosity of the ink increases, the surface tension changes remarkably, and the dryness of the printed matter is deteriorated. It causes problems such as

In order to solve these problems, for example,
It is disclosed that by using a solvent composed of water, glycerin and propylene glycol, it is possible to prevent both nozzle clogging and early drying on a recording medium after recording (see, for example, Patent Document 1). . However, regarding the evaluation of the dry state at the nozzle,
Recording is possible even if left unattended for 0 seconds or more ", and the redispersibility and the ejection performance after a long-time operation such as standing overnight is insufficient. It remained unresolved.

Further, there is disclosed a technique for preventing clogging by using an ethylene glycol lower fatty acid ester compound which enhances the solubility of the dye of the ink and also has the effect of a wetting agent (for example, Patent Document 2).
However, although it is possible to avoid clogging when a water-soluble dye is used as the colorant, it cannot be dealt with when a water-insoluble dye is used as the colorant.

Further, as a technique for preventing the evaporation of the solvent, when a polyoxyethylene alkyl ether compound having an alkyl group having 14 to 23 carbon atoms is added, the liquid crystal structure is formed at the gas-liquid interface to evaporate the solvent. It is disclosed that the above can be prevented (for example, refer to Patent Document 3).
However, as described in [0016], "It is preferable to use a water-soluble dye." In this case as well, when applied to a water-insoluble coloring material, there is a problem in dispersion stability and redispersibility of the coloring material. Remains.

As an example of a water-insoluble coloring material, an ink technique containing a pigment, a humectant, and a long-chain polyethylene oxide-containing dispersant is disclosed (see, for example, Patent Document 4). However, even with this technique, the precipitation of the solid matter composed of the pigment and the dispersant cannot be avoided, and an excessive cleaning operation is required to wash the precipitated solid matter.

[0012]

[Patent Document 1] JP-A-8-41396

[0013]

[Patent Document 2] Japanese Patent Laid-Open No. 10-251579

[0014]

[Patent Document 3] Japanese Patent Laid-Open No. 2000-265098

[0015]

[Patent Document 4] Japanese Patent Laid-Open No. 10-95944

[0016]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional ink for ink jet recording as described above,
Even when a water-insoluble coloring material is used as the coloring material component,
While maintaining the originally required storage stability and high-quality recorded image performance, it has excellent nozzle clogging prevention properties, good dispersion stability, and long device operation even during continuous operation. The present invention provides an inkjet recording ink having a good redispersibility, which enables stable ejection even after a pause.

[0017]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that an ink composition having excellent reliability in which the nozzles of an inkjet head are less likely to be clogged up when a small amount of water is added even after the ink is dried. It is thought that the above object can be achieved with an ink composition having good redispersibility that is easily redispersed without performing the above, and as a result of intensive studies, the above object can be achieved by using a specific compound. The inventors of the present invention have found out what can be done and have reached the present invention.

That is, the ink jet recording ink of the present invention is as follows.

(1) Water, a water-soluble organic solvent, a water-insoluble coloring material, a dispersant, and the following chemical formula (I)

[0020]

Embedded image R—O— (CH ₂ CH ₂ O) _n —H (I) (In the formula, R represents an alkyl group having 25 to 150 carbon atoms,
n represents 2 to 100. ) An ink for inkjet recording comprising a compound represented by

(2) The compound represented by the chemical formula (I) is
The ink for inkjet recording according to item (1), wherein R represents a 30-50 alkyl group and n is a compound represented by 10-50.

(3) The compound represented by the chemical formula (I) is
The ink for inkjet recording according to any one of the items (1) and (2), wherein the HLB is a compound of 10 or more.

(4) The water-insoluble coloring material is a water-insoluble coloring material selected from disperse dyes and oil-soluble dyes.
The inkjet recording ink according to any one of (3).

(5) The ink for ink jet recording according to any one of (1) to (3) above, wherein the water-insoluble coloring material is a disperse dye.

(6) The dispersant is an anionic surfactant,
(1) which is at least one selected from the group consisting of nonionic surfactants and polymer surfactants
The inkjet recording ink according to any one of items (5).

(7) The ink jet recording according to any one of the above items (1) to (6), wherein the content of the compound represented by the chemical formula (I) is 0.1 to 8% by weight based on the total weight of the ink. Ink.

(8) The content of the water-soluble organic solvent, the water-insoluble coloring material, the dispersant, and the compound represented by the chemical formula (I) is
5 to 50% by weight of the water-soluble organic solvent, based on the total weight of the ink,
Water-insoluble coloring material 0.5 to 15% by weight, dispersant 0.5 to 20
%, And the compound of formula (I) 0.1-8
The ink for inkjet recording according to any one of the items (1) to (7), which is contained in a weight percentage.

The compound represented by the chemical formula (I) used in the present invention has an alkyl group having 25 or more carbon atoms, unlike the polyoxyethylene higher alkyl ethers conventionally used in ink jet recording inks. The upper limit of the carbon number of the alkyl group is usually 150 or less. As a conventional example, a natural alcohol-based compound or a synthetic alcohol-based compound is commercially available, but the number of carbon atoms of these alkyl groups is generally about 12 to 18. Further, the above-mentioned Patent Document 3 describes a polyoxyethylene alkyl ether-based compound having an alkyl group having 14 to 23 carbon atoms.

However, even if these polyoxyethylene higher alkyl ethers having less than 25 carbon atoms are used, an ink composition having good redispersibility cannot be obtained when a water-insoluble coloring material is used as the coloring material.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. In the compound represented by the following chemical formula (I) used in the present invention, R represents an alkyl group having 25 to 150 carbon atoms, and by using a compound in which R has 25 or more carbon atoms, good redispersibility for inkjet recording is obtained. It can be an ink composition. Further, from the viewpoint of solubility in the water-based ink composition, R having a carbon number of 150 or less is suitable. The carbon number of R is preferably 30 to 50 carbon atoms, and particularly preferably an alkyl group having 30 to 35 carbon atoms. n
Is 2 to 100, preferably 10 to 50, particularly preferably 20 to 50. The alkyl group may be linear or branched, but a linear alkyl group is preferable.

HLB is 4 or more from the viewpoint of solubility in water,
It is preferably 10 or more, and particularly preferably 14 to 18.

[0032]

## STR3 ## _{R-O- (CH 2 CH 2} O) n -H (I) Compound of Formula (I), based on the total amount of the ink 0.1
-8% by weight is preferably used, more preferably 0.1-6% by weight, and particularly preferably 0.2-4% by weight. By using it in the range of 0.1 to 8% by weight, there is no problem that the viscosity of the ink becomes too high due to the excessive addition amount, and the desired effect can be exhibited, which is preferable.

Examples of the compound of the above formula (I) include:
"Unitox 420" manufactured by Petrolite Inc. (R is a linear alkyl group having 31 to 32 carbon atoms, n is about 3, HL
B = 4), "Unitox 450" (R is carbon number 31 to 31)
32 linear alkyl groups, n is about 10, HLB = 1
0), "Unitox 480" (R is carbon number 31-32
A linear alkyl group of n, about 40, HLB = 16),
"Unitox 520" (R is a linear alkyl group having 38 carbon atoms, n is about 3, HLB = 4), "Unitox 55"
0 "(R is a linear alkyl group having 38 carbon atoms, n is about 1
2, HLB = 10), "Unitox 720" (R is a linear alkyl group having 48 to 49 carbon atoms, n is about 4, HLB
= 4), “Unitox 750” (R is a carbon number of 48 to 4)
9 is a linear alkyl group, n is about 16, HLB = 10), and the like.

Examples of the water-soluble organic solvent used in the present invention include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol and glycerin. Polyhydric alcohols, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and other glycol ethers, isopropyl alcohol, methanol, ethanol, benzyl alcohol, and other alcohols, N- Bases such as methyl-2-pyrrolidone and triethanolamine Solvents.

Of the above water-soluble organic solvents, glycerin,
Diethylene glycol, polyethylene glycol 30
0, 400, propylene glycol are preferred. In particular,
Glycerin is preferred as a moisturizer.

These may be used alone or in admixture of two or more.

The content of these water-soluble organic solvents is preferably 5 to 50% by weight based on the total weight of the ink from the viewpoint of adjusting the viscosity of the ink and preventing clogging due to the moisturizing effect. It is more preferably 10 to 45% by weight, and particularly preferably 15 to 40% by weight.

As the water-insoluble coloring material, pigments, disperse dyes,
Examples include oil-soluble dyes.

The content of these water-insoluble coloring materials is generally 0.5 to 15% by weight based on the total weight of the ink, because dispersion stability is maintained and the required printing density is obtained.
Is preferred. It is more preferably 1 to 10% by weight.

Examples of the pigment include azo-based, phthalocyanine-based, quinacridone-based, perinone-based, perylene-based organic pigments, and inorganic pigments such as carbon black.

As disperse dyes and oil-soluble dyes, azo-based dyes,
Examples thereof include anthraquinone type, quinoline type, quinophthalone type, nitro type, coumarin type, styryl type, methine type, azomethine type, xanthene type, perinone type, perylene type, indoaniline type and phthalocyanine type dyes.

Of these, when dyeing polyester fibers or film products by sublimation dyeing after printing on paper, disperse dyes and oil-soluble dyes are preferable, and polyester fibers are dyed by direct ink jet printing. In this case, disperse dyes are particularly preferably used because of their great affinity to fibers and good dyeability.

The dispersant used in the present invention disperses a water-insoluble coloring material in an aqueous medium and is not particularly limited, but may be one suitable for combination with the compound represented by the above formula (I). It is sufficient to use an anionic surfactant, a nonionic surfactant, a polymer surfactant and the like. In particular, an anionic surfactant or a nonionic surfactant is preferable for dispersing the disperse dye or the oil-soluble dye, and an anionic surfactant is particularly preferable. A polymeric activator is preferably used for dispersing the pigment.

As the anionic surfactant, a formalin condensate of naphthalene sulfonate, a lignin sulfonate, a formalin condensate of a special aromatic sulfonate,
Formalin condensate of creosote oil sulfonate, polyoxyethylene alkyl ether sulfate, etc. may be mentioned.

Examples of the nonionic surfactant include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene derivative, oxyethylene / oxypropylene block copolymer and the like.

Further, as the polymer type surfactant, polyacrylic acid partial alkyl ester, polyalkylene polyamine, polyacrylic acid salt, styrene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, polyphosphoric acid, Examples thereof include polyvinyl alcohol, carboxyalkyl cellulose, polyvinylpyrrolidone, and methacrylic acid derivative.

The content of these dispersants is preferably 0.5 to 20% by weight based on the total weight of the ink for the purpose of maintaining good dispersion stability of the water-insoluble coloring material. It is more preferably 0.5 to 10% by weight, and particularly preferably 0.5 to 5%.
% By weight.

Various other additives may be added to the ink of the present invention, if necessary, within a range not hindering the achievement of the object of the present invention. For example, surface modifiers, hydrotropes, pH modifiers, viscosity modifiers, preservatives, fungicides, light stabilizers, chelating agents, defoamers, anti-curl agents and the like.

When the pigment is used as the water-insoluble coloring material, it may further contain a binder.

Among the above additives, the surface conditioner includes
Fluorine-based surfactants, polyether denatured formed polydimethylsiloxanes, including but an acrylic polymer, in the present invention, in particular polyether denatured polydimethylsiloxane or an acrylic polymer is preferred. These surface modifiers are effective in adjusting the surface tension of the ink and making the ink easily wet with the ink flow path system material, but 0.05 to 1% by weight, preferably, of the total weight of the ink, 0.1-
Used in the range of 0.5% by weight. If it is less than 0.05% by weight, the effect is small, and if it is used in excess of 1% by weight, the effect is hardly improved.

The method for adjusting the ink jet recording ink of the present invention is not particularly limited, but it is preferably adjusted by the method described below. That is, first, (1) a water-insoluble coloring material, the compound of the chemical formula (I), a dispersant, water, and, if necessary, a water-soluble organic solvent and the additive are mixed and stirred to prepare a preliminary dispersion liquid. After adjustment, (2) the preliminary dispersion liquid is dispersed by a wet medium mill such as a sand mill to obtain a color material dispersion liquid. (3) After adjusting the concentration by adding water, a water-soluble organic solvent and, if necessary, the additive to the color material dispersion liquid,
Use after filtering with filter paper.

In the above method, the compound of the chemical formula (I) may be added at the time of forming fine particles, at the time of adjusting the concentration, or may be added in divided portions.

In addition, when the compound of the above chemical formula (I) is added, from the viewpoint of workability, 10 to 1 prepared in advance is prepared.
It is preferable to use an aqueous solution of about 5% by weight. In this case, the amount of water added at the same time may be reduced accordingly.

The average particle size of the water-insoluble coloring material obtained by the above method is preferably 1 μm or less, more preferably 0.02.
Is about 0.2 μm.

Although the solvent, coloring material, dispersant and other components have been exemplified above, the present invention is not limited to these examples.

[0056]

The present invention will be described in more detail with reference to the following examples, but the embodiments of the present invention are not limited thereto. In the following Examples, "parts" means "parts by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

[Example 1] Red disperse dye base (C.I.
I. Disperse Red 60) 20 parts, sodium salt of β-naphthalene sulfonic acid formalin condensate of anionic surfactant as a dispersant (Demol N manufactured by Kao Corporation) 12 parts, "Unitox 480" (Chemical formula manufactured by Petrolite Co., USA) In the compound of (I), R has 31 carbon atoms
~ 32 straight chain alkyl groups, n about 40, HLB 16
(Corresponding to 5 parts) and 123 parts of water were used, and 330 parts of zircon beads having a diameter of 0.4 mm were used, and the mixture was atomized in a sand mill for 35 hours to obtain a dispersion liquid.

In this dispersion, 5 parts of "Unitox 480", 120 parts of glycerin as a water-soluble organic solvent, and polyether-modified polydimethylsiloxane as a surface modifier ("BYK-34" manufactured by BYK Japan KK) were used.
8 ") and 2.0 parts of water were further added to prepare an ink having a dye concentration adjusted to 5%. The average particle size of the dye was 0.10 μm.
Met.

Example 2 Instead of the red disperse dye base, a yellow disperse dye base (CI Disperse) was used.
Yellow 54) Example 1 except using 20 parts
In the same manner as in (1) above, the dispersion liquid was treated with 25 units of "Unitox 480" as the compound of the chemical formula (I).
Parts, 300 parts of glycerin as a water-soluble organic solvent, 2.5 parts of "BYK-348" as a surface conditioner, and further water to adjust the dye concentration to 2% to prepare an ink. The average particle size of the dye was 0.12 μm.

[Example 3] Blue disperse dye base (C.I.
I. Disperse Blue 72) 20 parts, sodium salt of a special aromatic sulfonic acid formalin condensate of anionic surfactant as a dispersant ("Demol SNB" manufactured by Kao Corporation) 12 parts, and the compound of the chemical formula (I) is " Using a mixture of 5 parts of Unitox 480 ″ and 123 parts of water and 330 parts of zircon beads having a diameter of 0.4 mm, atomization was carried out in the same manner as in Example 1, and 15 units of “Unitox 480” were added to this dispersion. Part, 180 parts of glycerin as a water-soluble organic solvent, an acrylic polymer as a surface conditioner (“BYK manufactured by BYK Japan KK”)
-381 ″) and 2.4 parts of water to adjust the dye concentration to 3.3% to prepare an ink. The average particle size of the dye was 0.08 μm.

Example 4 In the same manner as in Example 1, 40 parts of the dispersion obtained by forming fine particles was added with 10 parts of "Unitox 480" as the compound of the chemical formula (I) and 120 parts of glycerin as the water-soluble organic solvent. , As a surface conditioner "BY
An ink was prepared by adding 0.4 part of K-348 ″ and further water to adjust the dye concentration to 1.25%.

Example 5 Red disperse dye raw material (C.
I. Disperse Red 60) 20 parts, sodium salt of a special aromatic sulfonic acid formalin condensate of anionic surfactant as a dispersant ("Demol SNB" manufactured by Kao Corporation) 12 parts, "Unitox 480" 3 parts,
330 parts of zircon beads having a diameter of 0.4 mm was used in a mixture of 125 parts of water, and the mixture was atomized for 35 hours in a sand mill to obtain a dispersion liquid.

120 parts of glycerin as a water-soluble organic solvent and polyether-modified polydimethylsiloxane as a surface modifier (manufactured by BYK Japan KK)
"BYK-348") (2.0 parts), and water was further added to prepare an ink having a dye concentration adjusted to 5%. The average particle size of the dye was 0.10 μm.

Example 6 A yellow disperse dye base (CI Disperse) was used in place of the red disperse dye base.
Yellow 54) 20 copies, "Unitox 480"
Was microparticulated in the same manner as in Example 5 except that 4 parts of water and 124 parts of water were used, and 300 parts of glycerin as a water-soluble organic solvent and "BYK-34" as a surface conditioner were added to the dispersion.
An ink was prepared by adding 2.5 parts of 8 ″ and water to adjust the dye concentration to 2%. The average particle size of the dye is 0.12 μm.
Met.

Example 7 In the same manner as in Example 5, 40 parts of the dispersion obtained by forming fine particles was added with 3.3 parts of "Unitox 480" as the compound of the chemical formula (I) and glycerin as the water-soluble organic solvent. 120 parts, as a surface conditioner "B
An ink was prepared by adding 0.4 part of YK-348 ″ and water to adjust the dye concentration to 1.25%.

[Comparative Example 1] "Unitox 4" of Example 1
An ink was prepared in the same manner as in Example 1 except that the same amount of sodium salt of a β-naphthalenesulfonic acid formalin condensate (“Demol N” manufactured by Kao Corporation) which is an anionic surfactant was used instead of 80 ″. did.

[Comparative Example 2] "Unitox 4" of Example 1
Polyoxyethylene higher alkyl ether (“Emulgen 70” manufactured by Kao Corporation, which is a nonionic surfactant made of an alcohol having a carbon number of less than 25 as a raw material instead of “80”.
An ink was prepared in the same manner as in Example 1 except that the same amount of 7 ″) was used.

[Comparative Example 3] "Unitox 4" of Example 1
A polyoxyethylene higher alkyl ether (“Emulgen MS-110” manufactured by Kao Co., Ltd.), which is a nonionic surfactant made of natural alcohol (having 18 or less carbon atoms) as a raw material, was used in the same amount instead of 80 ″. An ink was prepared in the same manner as in Example 1.

[Comparative Example 4] An ink was prepared in the same manner as in Example 1 except that the same amount of "Unitox 480" was used instead of "Demol N" in Example 1. The particle size of the dye was 1 μm or more. When the ink obtained was left to stand, the dyes gradually aggregated to form a precipitate.
Therefore, when the dispersant was not used, the ink was inferior in storage stability and could not be used as an ink for inkjet recording.

Table 1 shows the proportions of components other than water in the ink compositions of Examples 1 to 7 and Comparative Examples 1 to 3.

[0071]

[Table 1]

The following tests were conducted on the inks of Examples 1 to 7 and Comparative Examples 1 to 3 above. The test results are shown in Table 2.

(1) Redispersibility test 0.5 g of the ink composition was thinly spread on the surface of a watch glass (φ90 mm), and then placed in a dryer kept at 60 ° C. and left to stand. After 1 hour, remove the watch glass from the dryer,
Observe the condition when the ink is gently rinsed with a small amount of water from the outside of the peripheral area where the ink has become dry.

Evaluation Criteria: (◯) Rapidly redispersion without aggregation. (A) A small thin film-like aggregate is observed, but it does not adhere to the glass surface. (X) A considerable amount of aggregates were observed and remained attached to the glass surface.

(2) Continuous Discharge Stability Test Using a commercially available large-sized inkjet plotter "JV2-130" (Piezo method) manufactured by Mimaki Engineering Co., Ltd., a printing resolution of 720 x 720 dpi, single color, solid printing, printing Continuous printing was performed under the condition of a width of 1200 mm until defective printing such as missing dots was recognized.

Evaluation criteria: (◯) No clogging for 5 hours or more. (△) Clogging occurred in 30 minutes to 1 hour. (X)
Clogging occurred within 30 minutes.

(3) Discharge property after being left for a long time After being continuously operated for 30 minutes under the above-mentioned printing conditions, it is left as it is for 48 hours, and after normal cleaning, a printing test is again performed to see if normal printing can be performed under the same conditions. went. Evaluation Criteria: (◯) The inkjet plotter was able to print normally with one predetermined cleaning of the head. (△)
Needs to be cleaned several times. (X) Does not recover even after further cleaning.

[0078]

[Table 2]

As is clear from these test results, Examples 1 to 7 of the present invention were excellent in redispersibility, and were excellent in continuous discharge stability and discharge property after being left for a long time. Comparative Example 1 in which the compound of I) was replaced with an anionic dispersant without using the compound I) had poor redispersibility and poor continuous ejection stability and ejection after being left for a long time. Further, Comparative Examples 2 and 3 in which the nonionic dispersant was replaced tended to be slightly better than those in which the anionic dispersant in Comparative Example 1 was replaced, but they are considerably inferior to the examples of the present invention. Was there.

Further, Comparative Example 4 in which the compound of the formula (I) was used without using the dispersant, was inferior in the storage stability of the ink and therefore could not be used as an ink for ink jet recording.

[0081]

The ink for ink jet recording using the water-insoluble coloring material of the present invention as a coloring material component, while maintaining the originally required storage stability and high-quality recorded image performance,
Ink with good redispersibility, excellent nozzle clogging prevention, and stable ejection with normal cleaning can be obtained even during continuous operation for a long period of time, even after suspending operation of the device for a long time. Have.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA04 EA14 FC01                 2H086 BA56 BA59 BA60 BA62                 4J039 AB02 AD03 AD06 AD09 AD14                       AD23 AE07 BC07 BC09 BC13                       BC34 BE01 BE02 BE07 BE08                       BE12 BE22 CA06 EA41 EA44                       GA24

Claims (8)

[Claims] 1. Water, a water-soluble organic solvent, a water-insoluble coloring material, a dispersant, and the following chemical formula (I): R—O— (CH ₂ CH ₂ O) _n —H (I) (wherein , R represents an alkyl group having 25 to 150 carbon atoms,
n represents 2 to 100. ) An ink for inkjet recording comprising a compound represented by 2. The ink for inkjet recording according to claim 1, wherein the compound represented by the chemical formula (I) is a compound in which R represents an alkyl group of 30 to 50 and n represents 10 to 50. 3. The compound represented by the chemical formula (I) is HL
The ink for inkjet recording according to claim 1, wherein B is a compound of 10 or more. 4. The ink for ink jet recording according to claim 1, wherein the water-insoluble coloring material is a water-insoluble coloring material selected from disperse dyes and oil-soluble dyes. 5. The ink for inkjet recording according to claim 1, wherein the water-insoluble coloring material is a disperse dye. 6. The dispersant is at least one selected from the group consisting of anionic surfactants, nonionic surfactants, and polymer surfactants. Inkjet recording ink. 7. The inkjet recording ink according to claim 1, wherein the content of the compound represented by the chemical formula (I) is 0.1 to 8% by weight based on the total weight of the ink. 8. The content of the water-soluble organic solvent, the water-insoluble colorant, the dispersant, and the compound represented by the chemical formula (I) is 5 to 50% by weight of the water-soluble organic solvent and water-insoluble with respect to the total weight of the ink. The inkjet according to any one of claims 1 to 7, wherein the coloring material is 0.5 to 15% by weight, the dispersant is 0.5 to 20% by weight, and the compound represented by the chemical formula (I) is 0.1 to 8% by weight. Recording ink.