JPH10158562A - Ink composition for ink jet recording and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pigment type ink composition for ink jet printing capable of finely dispersing a pigment, good in preservation stability and hardly providing both coagulation of the pigment and plugging of an ejecting orifice by including the pigment, a specific acrylic resin, a specified compound, a basic compound and an aqueous medium under a specific condition. SOLUTION: The objective ink composition for ink jet printing consists essentially of (A) a pigment, (B) an acrylic resin obtained by copolymerizing monomer components comprising 5-30 pts.wt. (meth)acrylic acid alkyl ester compound having an 8-20C long chain alkyl group, 5-30 pts.wt. monoethylenic α,β-unsaturated carboxylic acid monomer, and 40-90 pts.wt. other copolymerizable and radically polymerizable monomer, (C) a compound of the formula [R<1> is a 6-20C monovalent hydrocarbon having benzene ring, naphthalene ring or anthracene ring; R<2> is a 2-4C divalent hydrocarbon; (n) is 1-30], (D) a basic compound and (E) an aqueous medium, and obtained by regulating the weight ratio of components B/C to be (20/80) to (80/20) and the content of the total amount of components B and C to be 8-300 pts.wt.% based on 100 pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink composition for ink jet recording and a method for producing the same. More specifically, by preparing a circulating bead mill using ceramic beads having a diameter of 0.2 to 3.0 mm as a pulverizing medium, the pigment can be finely dispersed, and the obtained ink composition for inkjet recording can be stored stably. Good quality,
The present invention relates to a pigment type ink jet recording ink composition free from pigment aggregation and clogging of an ejection orifice, and a method for producing the same.

[0002]

2. Description of the Related Art Dyes have been widely used as colorants for ink compositions used in ink-jet recording systems. However, it is difficult to solve the problems of poor water resistance and poor light fastness. It has always been requested.

[0003] However, the pigment type ink composition at present has many problems to be overcome practically.
Among them, in particular, a technique of dispersing a pigment into fine particles, and a solution of aggregation of the pigment and clogging of an ejection orifice are major issues.

The mechanism by which aggregation of the pigment and clogging of the discharge orifice occur is considered as follows.

[0005] Since the pigment itself is insoluble in the ink medium, in order to use it as a colorant for the ink, it must be formed into fine particles and dispersed in the ink medium. However, as the pigment particles become finer, the specific surface area increases, and if the pigment surface is not sufficiently wetted, the dispersion stability is reduced and aggregation tends to occur.

[0006] In particular, in the ink composition used in the ink jet recording system, since a low viscosity and a high color density are required, it is necessary to make the pigment into finer particles, and the pigment tends to aggregate during storage.

[0007] In addition, the pigment type violently thickens when the solvent is dried as compared with the dye type, and when the pigment is agglomerated, the resolubility and redispersibility are reduced, and the pigment is discharged from the discharge orifice. Droplets easily form.

Therefore, in order to improve the wettability or thickening of the pigment surface, the re-dissolution and re-dispersibility of the dried ink,
A method using a polymer having a hydrophilic part and a hydrophobic part (for example, JP-A-56-147863) or a method using a surfactant (for example, JP-A-62-274)
No. 76) has been proposed, but the present situation is that sufficient performance has not yet been obtained.

[0009]

SUMMARY OF THE INVENTION The present invention provides a pigment type ink jet recording ink composition which can easily disperse a pigment into fine particles and which does not cause aggregation of the pigment or clogging of an ejection orifice, and a method for producing the same. The task is to provide.

[0010]

Means for Solving the Problems The present invention provides (1) a pigment,
An acrylic resin obtained by copolymerizing the following monomer components a to c, a compound represented by the general formula (1), a basic compound, and an aqueous medium are mainly constituted. ) Is the ratio of the acrylic resin / the compound represented by the general formula (1) = 20/80 to 80 /
20 (weight ratio) and contains the acrylic resin and the compound represented by the general formula (1) in a total amount of 8 to 300 parts by weight with respect to 100 parts by weight of the pigment. It relates to an ink composition.

A. (Meth) acrylic acid alkyl ester compound having a long-chain alkyl group having 8 to 20 carbon atoms, 5 to 30 parts by weight b. α, β-monoethylenically unsaturated carboxylic acid monomer 5 to 30 parts by weight c. Other copolymerizable radical polymerizable monomers 40 to 90 parts by weight However, the total of the above monomer components a + b + c is 100 parts by weight.

[0012]

Embedded image

(Wherein, R ¹ is a carbon atom having at least one of a benzene ring, a naphthalene ring and an anthracene ring)
20 monovalent hydrocarbon group, R ² is 2 C2-4
Valent hydrocarbon group, n represents an integer of 1 to 30).

Further, the present invention provides (2) the above general formula (1)
Wherein the compound represented by the formula (1) is a compound represented by the formula (2).

[0015]

Embedded image

(Wherein, R ³ is a monovalent hydrocarbon group having 12 to 15 carbon atoms having a biphenyl skeleton, and m is 10 to 20)
Represents an integer).

Further, the present invention provides (3) the aqueous medium,
The present invention relates to the ink composition for inkjet recording according to the above (1) or (2), comprising a compound obtained by adding 5 to 90 mol of ethylene oxide per 1 mol of polyglycerin.

Further, the present invention provides (4) the above (1) to
(3) An ink for ink-jet recording, which is prepared by a circulation type bead mill using ceramic beads having a diameter of 0.2 to 3.0 mm as a crushing medium. The present invention relates to a method for producing the composition.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of repeated studies to solve the above-mentioned problems, the present inventors have found that a pigment is obtained by using a circulating bead mill using ceramic beads having a diameter of 0.2 to 3.0 mm as a grinding medium. Can be easily dispersed into fine particles,
And a (meth) acrylic acid alkyl ester compound having an alkyl group having 8 to 20 carbon atoms, an α, β-monoethylenically unsaturated carboxylic acid monomer, and other copolymerizable radically polymerizable monomers. It has been found that by using the acrylic resin obtained by polymerization and the compound represented by the general formula (1) in a specific ratio in combination, it is possible to solve the aggregation of the pigment and the clogging of the discharge orifice. It has been reached.

Hereinafter, the present invention will be described in more detail.

First, as the pigment used in the ink composition for ink jet recording of the present invention, known inorganic and organic pigments that can be dispersed in an aqueous medium can be used. preferable.

The inorganic pigments usable herein include titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, navy blue, ultramarine, carbon black, graphite, etc., and the organic pigments include soluble azo pigments, insoluble Examples include azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, and the like. These pigments can be used alone or in combination of two or more.

The amount of the pigment used is about 1 to 30% by weight, preferably 2 to 10% by weight, based on the whole ink composition for ink jet recording. If the amount of the pigment used is less than the above range, the color density decreases, while if it is more than the above range, it becomes difficult to use the ink in terms of ink viscosity and fluidity.

Next, the acrylic resin used for dispersing the pigment in the ink composition for ink jet recording of the present invention is an acrylic resin obtained by copolymerizing the following monomer components a to c.

A. (Meth) acrylic acid alkyl ester compound having a long-chain alkyl group having 8 to 20 carbon atoms, 5 to 30 parts by weight b. α, β-monoethylenically unsaturated carboxylic acid monomer 5 to 30 parts by weight c. Other copolymerizable radical polymerizable monomers 40 to 90 parts by weight However, the total of the above monomer components a + b + c is 100 parts by weight.

The (meth) acrylic acid alkyl ester compound having an alkyl group having 8 to 20 carbon atoms as the component a includes, specifically, octyl (meth) acrylate and 2- (meth) acrylic acid 2-ester. Ethylhexyl ester, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate,
Tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and the like, and particularly long chains having 12 to 18 carbon atoms from the viewpoint of pigment dispersibility. Those having an alkyl group are preferred.

These alkyl (meth) acrylate compounds having a long-chain alkyl group having 8 to 20 carbon atoms include:
One type may be used alone, or two or more types may be used in combination.

The amount of the (meth) acrylic acid alkyl ester compound having a long-chain alkyl group having 8 to 20 carbon atoms is 5 to 30% by weight of the total monomers of the acrylic resin. When the amount of the compound is less than 5% by weight, the dispersibility of the pigment is reduced. On the other hand, when the amount is more than 30% by weight, the film becomes soft, so that the drying property and the film strength are reduced.

As the α, β-monoethylenically unsaturated carboxylic acid monomer as the component b, specifically, (meth) acrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic anhydride, maleic acid And maleic acid monoester. One of these α, β-monoethylenically unsaturated carboxylic acid monomers may be used alone, or two or more thereof may be used in combination.

The amount of the α, β-monoethylenically unsaturated carboxylic acid monomer used is 5% of the total monomers of the acrylic resin.
３０30% by weight. If the amount of the monomer is less than 5% by weight, good solubility in an aqueous medium cannot be obtained, while
If it exceeds 0% by weight, the water resistance of the printed image is undesirably reduced.

Examples of the other copolymerizable radical polymerizable monomers of the component c include methyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (meth) acrylate. , (Meth) acrylic acid butyl ester, (meth) acrylic acid isobutyl ester, (meth) acrylic acid t-butyl ester and other (meth) acrylic acid alkyl esters having 1 to 7 carbon atoms, (meth) acrylic acid 2- Examples thereof include hydroxyalkyl esters of (meth) acrylic acid having 2 to 8 carbon atoms, such as hydroxyethyl ester and hydroxypropyl (meth) acrylate. One of these other copolymerizable radically polymerizable monomers may be used alone, or two or more thereof may be used in combination.
The amount of the monomer used is 40% of the total monomer of the entire acrylic resin.
~ 90% by weight.

In order to obtain an acrylic resin using the above-mentioned monomer components, a boiling point of 50% is obtained in an atmosphere of an inert gas such as nitrogen.
Organic solvent at a temperature of up to 200 ° C., for example, a mono- or polyalkylene glycol or a water-miscible solvent such as an ether or ester solvent thereof, an acetate ester solvent or the like, or a water-immiscible solvent such as an aromatic hydrocarbon solvent or a ketone solvent A monomer is added and mixed therein, and a reaction initiator such as ditertiary butyl peroxide, benzoyl peroxide, azobisisobutyronitrile, and the like are added.
After copolymerization for a period of time, preferably 4 to 8 hours, a method of removing the organic solvent as necessary can be used.

Usually, the acrylic resin is used as an aqueous resin varnish dissolved in an aqueous medium in the presence of a basic compound.

The acrylic resin used in the present invention is:
In order to make the ink viscosity appropriate, the weight average molecular weight is 5,
000-100,000, preferably 8,000-3
In the case where the resistance of the ink film is required, the glass transition temperature (Tg)
Is preferably room temperature or higher.

Next, the compound represented by the general formula (1) used for dispersing the pigment in the ink composition for ink jet recording of the present invention will be described.

[0036]

Embedded image

(In the formula, R ¹ represents a benzene ring, a naphthalene ring, or an anthracene ring having at least one carbon atom having 6 to 6 carbon atoms.
20 is a monovalent hydrocarbon group, and R ² has 2 to 4 carbon atoms.
Wherein n is an integer of 1 to 30, preferably 8 to 20 from the viewpoint of water-solubility of the compound represented by the general formula (1) and viscosity of the obtained ink composition for inkjet recording. Is an integer).

Specific examples of the compound represented by the general formula (1) include phenol, alkylphenol, benzyl alcohol, naphthol, hydroxybiphenyl, biphenylalkanol, hydroxyanthracene and the like, to which an alkylene oxide having 2 to 4 carbon atoms is added. Can be exemplified.

As the alkylene oxide to be added,
Ethylene oxide, propylene oxide, butylene oxide and the like can be mentioned, but ethylene oxide is preferred from the viewpoint of solubilizing the compound represented by the general formula (1).

In the present invention, it is preferable to use the compound represented by the general formula (2) among the compounds represented by the general formula (1) from the viewpoint of the effect of dispersing the pigment.

[0041]

Embedded image

(Wherein R ³ is a monovalent hydrocarbon group having a biphenyl skeleton and having 12 to 15 carbon atoms, m is 10 to 20)
Is an integer).

Specific examples of the compound represented by the general formula (2) include compounds obtained by adding ethylene oxide to hydroxybiphenyl, biphenylmethanol, biphenylethanol, biphenylpropanol and the like.

In the present invention, as described above, it is important to use the acrylic resin specified in the present invention in combination with the compound represented by the general formula (1), and the ratio is specified in the present invention. Acrylic resin / compound represented by general formula (1) = 20/80 to 80/20, preferably 30/70
７０70/30 (weight ratio). When the ratio of the acrylic resin / the compound represented by the general formula (1) deviates from the predetermined ratio, the pigment dispersibility decreases.

In the ink jet recording ink composition of the present invention, the amount of the pigment dispersant (the sum of the acrylic resin specified in the present invention and the compound represented by the general formula (1)) for dispersing the pigment is determined. The lower limit is a necessary amount for improving the wettability of the pigment, and is 10% by weight of the amount of the pigment used.
It is about. Further, the upper limit of the amount of the pigment dispersant used in the present invention is, if all of the fixing of the inkjet recording ink composition and the re-dissolution of the dried ink are achieved by the pigment dispersant of the present invention, the amount of the pigment used Up to about 300% by weight, but usually up to 100% by weight. Further, the pigment dispersant used in the present invention is desirably contained in an amount of 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, based on the whole inkjet recording ink composition.

Further, the ink composition for ink jet recording of the present invention contains a styrene-acrylic acid resin or a styrene-maleic acid resin having a carboxyl group in the molecule for the purpose of fixing the ink and re-dissolving the dried ink. An aqueous resin such as a resin, particularly preferably a styrene-maleic acid-based resin can be used in combination.

The basic compounds used for dissolving the acrylic resin specified in the present invention in an aqueous medium include alkylamines such as butylamine and triethylamine, and alkanolamines such as monoethanolamine, diethanolamine and triethanolamine. , Morpholine, aqueous ammonia, sodium hydroxide, and the like. Among them, from the viewpoint of reducing clogging of the discharge orifice, a combination of a basic compound with high volatility and a basic compound with low volatility is used. Is desirable. Next, as the aqueous medium used in the ink composition for inkjet recording of the present invention, water and a water-miscible solvent can be used for the purpose of ejection stability, drying properties, and other purposes.

Here, examples of the water-miscible solvent include lower alcohols, polyhydric alcohols and derivatives thereof, and nitrogen-containing cyclic compounds.

Specifically, lower alcohols such as methanol, ethanol, normal propanol and isopropanol, ethylene glycol, propylene glycol,
Polyethylene glycol, polypropylene glycol,
Polyhydric alcohols such as glycerin, polyglycerin, and ethylene oxide adduct of polyglycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, etc. Polyhydric alcohol derivatives of
Nitrogen-containing cyclic compounds such as N-methylpyrrolidone and N-ethylpyrrolidone can be used. In addition to water, ethylene oxide adducts of polyglycerin (5 to 1 mol of polyglycerin) are used in addition to water in view of ejection stability and drying properties. It is preferable that 90 mol of ethylene oxide is added) and another polyhydric alcohol. In this case, it is preferable to use 1 to 20 parts by weight of an ethylene oxide adduct of polyglycerin and 1 to 20 parts by weight of other polyhydric alcohols with respect to 100 parts by weight of water.

As a water-miscible solvent, acetone, ethyl acetate and the like are not preferred because they may damage the printing device.

The ink composition for ink-jet recording of the present invention may further comprise a silicone-based surfactant, a surfactant containing fluorine, another surfactant, a viscosity modifier, a defoaming agent, if necessary. Various additives such as an agent can be added.

In the production of the ink composition for ink jet recording using the above components, first, the pigment, the specific acrylic resin of the present invention, the compound represented by the general formula (1), the basic compound, the aqueous medium, Accordingly, after mixing an aqueous resin having a carboxyl group in a molecule and various additives for the purpose of fixing and re-dissolving the dried ink, a diameter of 0.2 to 3.
This can be performed by kneading the meat using a circulation type bead mill using 0 mm ceramic beads as a grinding medium, and further adding and mixing the remaining materials. More preferably, by using a circulating bead mill using zirconia beads having a diameter of 0.2 to 1.0 mm as grinding media,
The pigment can be easily dispersed in fine particles, and filtering becomes easy.

[0053]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

<Synthesis Example of Acrylic Resin>
A four-necked flask equipped with a nitrogen gas inlet tube was charged with 350 parts of ethyl acetate, heated to 75 to 85 ° C., and then, while introducing nitrogen gas, 250 parts of a monomer mixture having a composition ratio in Table 1; A mixture of 2.5 parts of di-tert-butyl peroxide as a reaction initiator was added dropwise over 2 hours. After further polymerizing for 2 hours while maintaining the same temperature,
The solvent was distilled off under reduced pressure, and each acrylic resin 1
~ 4.

[0055]

[Table 1]

<Preparation of Acrylic Resin Varnish> Each of the acrylic resins 1 to 4 obtained by the above synthesis examples was 40
After crushing 0 parts, the mixture was stirred and mixed in 600 parts of water in which a neutralized amount of triethanolamine was dissolved, and heated and dissolved at 80 ° C. to obtain acrylic resin varnishes 1 to 4 having a solid content of 40%.

<Examples and Comparative Examples of Inkjet Recording Ink Compositions> Examples 1 to 5 and Comparative Examples 1 to 4 The ink jet recording ink compositions of Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 2. Was prepared.

Next, a specific preparation method will be described.

Carbon black (Prntex 35, manufactured by Texa Co.), acrylic resin varnishes 1-4, a compound obtained by adding an average of 14 moles of ethylene oxide to p-hydroxybiphenyl, and ion-exchanged water were stirred and mixed to give a diameter of 0.3.
After kneading using a circulating bead mill using zirconia beads of 0.2 mm in diameter as a crushing medium, a compound obtained by adding 20 mol of ethylene oxide to ion-exchanged water, diethylene glycol, and polyglycerin (degree of polymerization: 4) is added, followed by stirring and mixing. The ink compositions for inkjet recording of Examples 1 to 5 and Comparative Examples 1 to 3 were obtained.

Further, carbon black (Prtex 3)
5, manufactured by Tegusa Co., Ltd.), acrylic resin varnish 1, BYK-1
90 (ethylene oxide modified product of styrene-maleic acid copolymer, manufactured by BYK Chemical Co., Ltd.) and ion-exchanged water with stirring and using a circulating bead mill using zirconia beads having a diameter of 0.3 mm as a grinding media. After kneading,
A compound in which 20 mol of ethylene oxide was added to ion-exchanged water, diethylene glycol, and polyglycerin (degree of polymerization: 4) was added and mixed by stirring. Thus, an ink composition for inkjet recording of Comparative Example 4 was obtained.

<Evaluation Test> Examples 1 to 5 and Comparative Example 1
Test evaluation of storage stability and clogging of the discharge orifice of Nos. To 4 were performed by the following methods. The results are shown in Table 2.

[Storage Stability] The test ink was sealed in a glass container and stored for one month at an ambient temperature of 50 ° C., and the storage stability was evaluated from the change in state. A: No change is observed in the state. B: Separation of the pigment was observed but no sedimentation was observed. C: Separation and sedimentation of the pigment are present, but both are eliminated immediately if shaken gently. D: Separation and sedimentation of the pigment occur, and sedimentation does not disappear even if shaken gently.

[Clogging of Discharge Orifice] A test ink is filled in a head of a recording apparatus having an on-demand type multi-head which performs recording by applying thermal energy to ink in the recording head to generate droplets and perform capping. Was left for 3 days at an ambient temperature of 20 ° C., and clogging of the discharge orifice was evaluated under conditions enabling printing.

A: Printing can be performed by cleaning the ejection orifice 0 times. B: Printing can be performed by cleaning the ejection orifice once or twice. C: Printing can be performed by cleaning the ejection orifice 3 to 5 times. D: Cleaning of the ejection orifice is performed 6 times or more. Printing is possible E: Printing is impossible even if the ejection orifice is cleaned many times <Examples and Comparative Examples of Production Method of Ink Composition for Inkjet Recording> Examples 1 to 5 and Comparative Examples 5 to 9 Examples 1 to 5 The composition and production method of the ink composition for ink jet recording are the same as described above.

The compositions of the ink compositions for ink jet recording of Comparative Examples 5 to 9 were as shown in Table 2 in Examples 1 to 5, respectively.
But the manufacturing method was changed as follows.

That is, carbon black (Prnte
x35, manufactured by Tegusa Co., Ltd.), acrylic resin varnish 1, a compound obtained by adding 14 moles of ethylene oxide to p-hydroxybiphenyl, and ion-exchanged water, followed by stirring and kneading using a dyno mill, followed by ion-exchanged water, diethylene glycol, poly A compound obtained by adding 20 mol of ethylene oxide to glycerin (degree of polymerization: 4) is added, and mixed by stirring.
Ink compositions for inkjet recording of Comparative Examples 5 to 9 were produced.

<Evaluation Test> Examples 1 to 5 and Comparative Example 5
Test evaluation of filtering properties of the ink compositions for inkjet recording of Nos. To 9 was performed by the following method.

[Filtering Property] The ink compositions for ink jet recording of Examples 1 to 5 and Comparative Examples 5 to 9 were
Judgment was made by using a μm filter based on whether or not the light passed.

As a result, the ink compositions for ink jet recording of Examples 1 to 5 prepared using a circulating type bead mill passed through a 3 μm filter, while those of Comparative Examples 5 to 9 prepared using a dyno mill. The ink composition for inkjet recording hardly passed through the 3 μm filter.

[0070]

[Table 2]

[0071]

As described above, the ink composition for ink-jet recording of the present invention has the following features.
The pigment can be easily dispersed in fine particles by using a circulation type bead mill using ceramic beads having a diameter of 0.2 to 3.0 mm as a crushing medium, and an alkyl (meth) acrylate having an alkyl group having 8 to 20 carbon atoms. An acrylic resin obtained by copolymerizing an ester compound, an α, β-monoethylenically unsaturated carboxylic acid monomer, and other copolymerizable radically polymerizable monomers with a compound represented by the general formula (1) Is used together at a specific ratio, it is possible to prevent aggregation of the pigment and clogging of the discharge orifice.

Claims (4)

[Claims] 1. A pigment, an acrylic resin obtained by copolymerizing the following monomer components a to c, a compound represented by the general formula (1), a basic compound, and an aqueous medium, The ratio of the acrylic resin and the compound represented by the general formula (1) is acrylic resin / the compound represented by the general formula (1) = 20/80 to 80/20 (weight ratio), and 100 parts by weight of the pigment On the other hand, an ink composition for ink jet recording comprising a total amount of the acrylic resin and the compound represented by the general formula (1) of 8 to 300 parts by weight. a. (Meth) acrylic acid alkyl ester compound having a long-chain alkyl group having 8 to 20 carbon atoms, 5 to 30 parts by weight b. α, β-monoethylenically unsaturated carboxylic acid monomer 5 to 30 parts by weight c. Other copolymerizable radical polymerizable monomers 40 to 90 parts by weight However, the total of the above monomer components a + b + c is 100 parts by weight. Embedded image (Wherein, R ¹ is a monovalent hydrocarbon group having 6 to 20 carbon atoms having at least ^one of a benzene ring, a naphthalene ring, and an anthracene ring, and R ² is a divalent hydrocarbon having 2 to 4 carbon atoms.) And n represents an integer of 1 to 30). 2. A compound represented by the general formula (1):
The ink composition for inkjet recording according to claim 1, which is a compound represented by the general formula (2). Embedded image (Wherein, R ³ has 12 to 12 carbon atoms having a biphenyl skeleton)
A monovalent hydrocarbon group of 15 and m represents an integer of 10 to 20). 3. The ink composition for inkjet recording according to claim 1, wherein the aqueous medium contains a compound obtained by adding 5 to 90 mol of ethylene oxide per 1 mol of polyglycerin. 4. The ink composition for ink jet recording according to claim 1, which has a diameter of 0.2 to 3.0 mm.
A method for producing an ink composition for ink-jet recording, characterized in that the composition is prepared by a circulation type bead mill using the ceramic beads as a pulverizing medium.