JP2021138884A - Amphiphilic polymer, colorant dispersant and water-based inkjet ink composition - Google Patents

Abstract

To provide an amphiphilic polymer that allows a dispersion colorant to be stably dispersed in an aqueous medium, and can improve the fastness of the dispersion colorant attached to an attachment target.SOLUTION: An amphiphilic polymer has an amphiphilic unit having a hydrophilic group and a hydrophobic group, and a reactive unit having a reactive group.SELECTED DRAWING: None

Description

The present invention relates to amphipathic polymers, colorant dispersions and water-based inkjet ink compositions.

Color material dispersion is an important process in the production of paints and inks. The quality of color material dispersion depends on the optical properties such as gloss, coloring power, and hiding power of the product, the rheological properties such as viscosity, fluidity, leveling property, and flow property, and the stability over time such as sedimentation and the generation of agglomerates. Affects sex, etc.

Therefore, a technique has been proposed in which a color material contained in a paint or ink is coated with a dispersant. For example, Patent Document 1 discloses an inkjet recording ink in which pigment particles are dispersed with a styrene-acrylic acid-based resin.

JP-A-2017-002096

However, with the resin described in the prior art, the dispersion of the coloring material is still unstable, and it is not always sufficient to fix the coloring material to the adhesion target. Therefore, there is a demand for an amphipathic polymer capable of stably dispersing a dispersible color material in an aqueous medium and improving the fastness of the dispersed color material adhering to the adhesion target.

One aspect of the amphipathic polymer according to the present invention is
An amphipathic unit containing hydrophilic and hydrophobic groups,
Reactive units containing reactive groups and
Have.

One aspect of the color material dispersion liquid according to the present invention is
With the amphipathic polymer of the above aspect,
Dispersible color material and
including.

One aspect of the water-based inkjet ink composition according to the present invention is
The color material dispersion liquid of the above aspect is contained.

An embodiment of the present invention will be described below. The embodiments described below describe examples of the present invention. The present invention is not limited to the following embodiments, and includes various modifications implemented without changing the gist of the present invention. It should be noted that not all of the configurations described below are essential configurations of the present invention.

In the present specification, "(meth) acrylic" means acrylic or methacryl, and "(meth) acrylate" means acrylate or methacrylate.

1. 1. Amphiphile Polymer The amphipathic polymer according to one embodiment of the present invention has an amphipathic unit containing a hydrophilic group and a hydrophobic group, and a reactive unit containing a reactive group.

1.1. Structure of amphipathic polymer The amphipathic polymer has an amphipathic unit and a reactive unit. Here, the unit refers to a structural unit derived from a monomer of an amphipathic polymer. Therefore, the amphipathic unit and the reactive unit may be arranged regularly or irregularly (randomly) in the amphipathic polymer, respectively. In the present specification, the term amphipathic unit or reactive unit refers to one or a set of each of the amphipathic unit or reactive unit contained in the amphipathic polymer.

1.1.1. Amphiphilic unit The amphipathic unit contains hydrophilic and hydrophobic groups.

(A) Hydrophilic group The hydrophilic group of the amphipathic unit is a site having a higher affinity for an aqueous medium than the hydrophobic group. In other words, a hydrophilic group is a group that has a lower affinity for a coloring material than a hydrophobic group.

Here, the term hydrophilic group does not mean that only the group expresses the hydrophilicity of the amphipathic polymer, and a part or all of the hydrophilicity of the amphipathic polymer is hydrophilic. It means that the group is responsible. Therefore, the hydrophobic group described later may have a hydrophilic moiety, and the hydrophilic group may have a hydrophobic moiety. However, hydrophilic groups are responsible for much of the hydrophilicity of amphipathic polymers.

The hydrophilic group may be arranged in the main chain of the amphipathic polymer, or may be arranged as a side chain or a substituent.

Examples of the hydrophilic group include an oligooxyethylene chain, a carboxyl group, a hydroxyalkyl group, a sulfonic acid group, a phosphoric acid group, an alkyl carboxylate group, and a group containing a structure selected from an ester group of a carboxylic acid and an alkylene diol. It can be exemplified. The structure of the hydrophilic group may be the same or different among multiple amphipathic units. Further, the number of hydrophilic groups contained in one amphipathic unit may be one or more.

(B) Hydrophobic group The hydrophobic group of the amphipathic unit is a site having a lower affinity for an aqueous medium than the hydrophilic group. The hydrophobic group is a site that shows more affinity for the dispersible color material as compared with the hydrophilic group when the amphipathic polymer is used for the dispersion of the dispersible color material.

Here, the term hydrophobic group does not mean that only the group expresses the hydrophobicity of the amphipathic polymer, and a part or all of the hydrophobicity of the amphipathic polymer is hydrophobic. It means that the group is responsible. However, hydrophobic groups are responsible for much of the hydrophobicity of amphipathic polymers.

The hydrophobic group may be arranged in the main chain of the amphipathic polymer, or may be arranged as a side chain or a substituent.

The structure of the hydrophobic group is not particularly limited, but is a carboxylic acid ester group derived from a carboxyl group of (meth) acrylic acid such as a carboxylic acid alkyl ester group, a carboxylic acid cycloalkyl ester group, and a carboxylic acid aryl ester group. Examples thereof include a group having an aromatic ring such as a phenyl group, a benzyl group, a pyridinyl group, and an imidazolyl group, a group selected from a cyclohexyl group, a phenoxy group, and a phenoxymethyl group. The number of carbon atoms of alkyl, cycloalkyl, and aryl in the exemplified ester group is preferably 1 or more and 10 or less, and more preferably 1 or more and 6 or less.

Further, the hydrophobic group is more preferably selected from a cyclohexyl group, a phenoxy group, and a phenoxymethyl group.

The structure of the hydrophobic group may be the same or different among multiple amphipathic units. Further, the number of hydrophobic groups contained in one amphipathic unit may be one or more.

The amphipathic unit may contain a structure derived from the monomer unit represented by the following formula (1).

（式（１）中、Ｘは、直鎖状、分岐状若しくは環構造を含む炭素数３以上のアルキル基、直鎖状、分岐状若しくは環構造を含む炭素数３以上のアルコキシ基、フェニル基、フェノキシ基、又は、フェノキシメチル基を表し、Ｙは、−ＯＲ、−Ｏ（ＣＨ_２ＣＨ_２Ｏ）_ｐ−ＣＨ_２ＣＨ_３、−（ＯＣＨ_２ＣＨ_２）_ｐＳＯ_３Ｈ、−（ＯＣＨ_２ＣＨ_２）_ｐＣＯ_２Ｈ、−（ＯＣＨ_２ＣＨ_２）_ｐＰＯ_４Ｈ_２、−Ｏ（ＣＨ_２ＣＨ_２Ｏ）_ｐＨ、−Ｏ（ＣＨ_２）_ｑＯＨで表されるいずれかの基を表し、Ｒは、水素、又は、直鎖状、分岐状若しくは環状の炭素数１以上６以下のアルキル基を表し、ｐは１以上６以下の整数を表し、ｑは２以上８以下の整数を表す。）

(In the formula (1), X is an alkyl group having 3 or more carbon atoms including a linear, branched or ring structure, an alkoxy group having 3 or more carbon atoms including a linear, branched or ring structure, and a phenyl group. , Phenoxy group, or phenoxymethyl group, where Y is -OR, -O (CH ₂ CH ₂ O) _p -CH ₂ CH ₃ ,-(OCH ₂ CH ₂ ) _p SO ₃ H,-(OCH ₂₎ CH ₂ ) _p CO ₂ H,-(OCH ₂ CH ₂ ) _p PO ₄ H ₂ , -O (CH ₂ CH ₂ O) _p H, -O (CH ₂ ) _q OH R represents hydrogen or a linear, branched or cyclic alkyl group having 1 or more and 6 or less carbon atoms, p represents an integer of 1 or more and 6 or less, and q represents an integer of 2 or more and 8 or less. show.)

Here, examples of the alkyl group having 3 or more carbon atoms including the linear, branched or ring structure of X include n-propyl, i-propyl, cyclopropyl, n-butyl, sec-butyl, tret-butyl and pentyl. , Hexyl, cyclohexyl, heptyl, octyl and the like. Examples of the alkoxy group having 3 or more carbon atoms including a linear, branched or ring structure of X include propoxy, butoxy, pentyloxy, and hexyloxy. Examples of the linear, branched or cyclic alkyl group having 1 or more and 6 or less carbon atoms of R include methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, sec-butyl and tret-. Butyl, pentyl, hexyl, cyclohexyl and the like can be mentioned.

When the amphipathic unit is formed by polymerizing the monomer unit represented by the above formula (1), both a hydrophilic group and a hydrophobic group are added to one of the carbons in the main chain of the amphipathic polymer. Is an amphipathic unit with a structure that binds to. By adopting such a structure in the amphipathic unit, hydrophilic groups and hydrophobic groups can be arranged spatially close to each other. As a result, when the dispersible coloring material is dispersed in an aqueous medium using an amphipathic polymer, as compared with the case where the spatial distance between the aqueous group and the hydrophobic group is long as in the case of a block copolymer, for example. Therefore, the site that adsorbs to the dispersible coloring material of the amphipathic polymer and the site that is compatible with the aqueous medium become close to each other. Therefore, the dispersible color material can be dispersed more efficiently, and more stable dispersion can be obtained.

The ratio of the hydrophobic group to the hydrophilic group in the amphipathic unit is not particularly limited and can be determined in consideration of the balance between hydrophobicity and hydrophilicity. On the other hand, the proportion of the hydrophobic group is preferably 20.0 mol% or more and 60.0 mol% or less, more preferably 30.0 mol% or more and 50.0 mol% or less, and further preferably 35.0 mol% or more and 45.0 mol% or less.

The ratio of the amphipathic unit to all the units constituting the amphipathic polymer according to the present embodiment is preferably 10.0 mol% or more and 80.0 mol% or less, and more preferably 20.0 mol% or more and 70. It is 0 mol% or less, more preferably 30.0 mol% or more and 70.0 mol% or less. When the ratio of the amphipathic units is within the above range, the dispersion stability in the case of a color material dispersion liquid becomes better.

1.1.2. Reactive Units Amphiphilic macromolecules contain reactive units. The reactive unit contains a reactive group. Examples of the reactive group include a blocked isocyanate group. A blocked isocyanate group is an isocyanate group protected by a protecting group.

Since the reactive unit has a blocked isocyanate group, a color material dispersion using a dispersible color material for dispersing the amphoteric polymer in an aqueous medium is attached to an object having a hydroxyl group such as cellulose. When the hydroxyl group is deprotected, the hydroxyl group can be reacted with the regenerated isocyanate group. As a result, the dispersible coloring material can be prevented from falling off from the adhesion target. For example, when a cotton fabric is printed, the frictional fastness of the printed material can be improved.

The isocyanate group is a highly reactive group and easily reacts with water in an aqueous medium and is unstable. However, by using a blocked isocyanate group protected by a protecting group, the isocyanate group can be stably used even in an aqueous medium. In other words, by masking (protecting) a highly reactive isocyanate group with a blocking agent, it is stably present as a blocked isocyanate group in an aqueous medium. Then, the blocking agent is dissociated (deprotected) by heat treatment, and the isocyanate group is regenerated in an aqueous medium, thereby exhibiting good reactivity with a substance having active hydrogen such as cellulose.

Examples of the blocking agent capable of forming a protecting group include ε-caprolactam, methylethylketoxim, 1,2,4-triazole, 3,5-dimethylpyrazole and the like. The structure of each blocking agent is shown below, and the bonds involved in the protection of the isocyanate group are shown by broken lines.

The reactive unit may contain, for example, a structure derived from the monomer unit represented by the following formula (2).

(In the formula (2), R is represented by any of the following formulas (3), (4), formula (5) and formula (6). Formula (3), formula (4), formula ( In 5) and formula (6), the asterisk "*" represents the binding site.)

Since the reactive unit contains a structure derived from the monomer represented by the above formula (2), the blocked isocyanate group can be introduced into the amphipathic polymer, and the amphipathic polymer is stably present in the aqueous medium. Can be made to. Then, by heating, an isocyanate group is generated, and the isocyanate group can react with a hydroxyl group, an amino group, or the like. When cellulose is contained in the target to which the amphipathic polymer is attached, the isocyanate group of the amphipathic polymer reacts with the hydroxyl group of the cellulose to form a urethane bond, and both can be chemically bonded. ..

A urethane bond is formed by the reaction between the isocyanate group and the hydroxyl group. However, the target with which the isocyanate group reacts is not limited to the hydroxyl group, and the reaction partner may be changed according to various chemical structures contained in the target. For example, when an isocyanate group and an amino group react with each other, a urea bond (urea bond) is formed, a plurality of isocyanate bonds react with water to form a urea bond, and a reaction between the urea bond and the isocyanate group causes a bullet bond. , An alphanate bond is formed by the reaction between the urethane bond and the isocyanate group. Since these bonds can be positively generated or not generated depending on the reaction temperature or the like, the bonds may be generated according to the chemical structure existing in the attachment target of the amphipathic polymer. can.

The proportion of the reactive unit in all the units constituting the amphipathic polymer according to the present embodiment is preferably 1.0 mol% or more and 30.0 mol% or less, and more preferably 3.0 mol% or more and 20.0 mol. % Or less, more preferably 5.0 mol% or more and 15.0 mol% or less. When the proportion of the reactive unit is within the above range, sufficient frictional fastness can be obtained in the adhesion target when the color material dispersion liquid or the water-based inkjet ink composition is used.

11.3. Branched structure The amphipathic polymer may have a branched structure. Since the amphipathic polymer has a branched structure, when it is used for dispersing the dispersible coloring material in an aqueous medium, it is easily adsorbed to the dispersible coloring material in a mesh pattern, and the dispersion stability can be further improved. .. Further, the viscosity of the color material dispersion liquid or the water-based inkjet ink composition can be further lowered.

The method for introducing the branched structure into the amphipathic polymer is not particularly limited, but for example, it can be introduced using a branched agent. As the branching agent, for example, a compound represented by the following formula (7) can be used.

When introducing a branched structure into an amphipathic polymer, the frequency and generation of branching are not particularly limited. The branching generation is, for example, 2 or more and 10 or less, preferably 3 or more and 5 or less.

1.1.4. Third unit The amphipathic polymer according to the present embodiment may have a third unit in addition to the amphipathic unit and the reactive unit. The third unit may be hydrophilic or hydrophobic. The third unit may be arranged regularly or randomly in the amphipathic polymer. In the present specification, the term "third unit" refers to one or a set of the third units contained in the amphipathic polymer.

When the third unit contains a hydrophilic moiety, the hydrophilic moiety may include an oxyethylene group, an oligooxyethylene group, a carboxy group, a sulfonic acid group, a phosphoric acid group and the like. When the third unit contains a hydrophobic moiety, it may contain an alkyl group, an alkyl ether group, an aryl group and the like.

When the amphipathic polymer according to the present embodiment contains a third unit, the ratio of the third unit to all the units is preferably 0.1 mol% or more and 30.0 mol% or less, more preferably 1.0 mol. % Or more and 20.0 mol% or less, more preferably 2.0 mol% or more and 10.0 mol% or less. When the third unit is included, it may be possible to adjust the strength and balance of hydrophilicity and hydrophobicity of the amphipathic polymer.

1.2. Synthesis of amphipathic polymer The amphipathic polymer according to the present embodiment can be synthesized by polymerizing a monomer having a structure of an amphipathic unit and a monomer having a structure of a reactive unit. When the amphipathic polymer has a branched structure, it can be synthesized by appropriately using a branching agent. The polymerization method is not particularly limited, and various known methods can be used. The amphipathic polymer may be synthesized in one step by a copolymerization method, or may be synthesized by modification, modification, or the like after polymerization.

1.3. Number Average Molecular Weight and Dispersion Ratio The lower limit of the number average molecular weight (Mn) of the amphipathic polymer according to the present embodiment is preferably 8000, more preferably 9000, and particularly preferably 10000. The upper limit of the number average molecular weight (Mn) of the amphipathic polymer according to the present embodiment is preferably 20000, more preferably 18000, and particularly preferably 16000. When the number average molecular weight (Mn) of the amphipathic polymer is within the above range, the dispersion stability of the color material and the storage stability of the dispersion liquid containing the color material when the color material is dispersed in an aqueous medium are used. Can be made better. Further, when the amphipathic polymer according to the present embodiment is used in the water-based inkjet ink composition described later, the ejection stability by the inkjet method can be further improved. The number average molecular weight (Mn) of the amphipathic polymer is a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography (GPC).

Further, the weight average molecular weight (Mw) / number average molecular weight (Mn) of the amphoteric polymer according to the present embodiment, that is, the so-called dispersion ratio is preferably 1.1 to 2.0, and 1.1 to 1 It is preferably .8, more preferably 1.1 to 1.5. Generally, the value of the dispersion ratio is considered to mean the spread of the molecular weight distribution, and the closer this value is to 1, the narrower the molecular weight distribution is. Since the amphipathic polymer according to the present embodiment has a spread of molecular weight distribution within the above range, the dispersion stability of the color material and the dispersion including the color material when the color material is dispersed in an aqueous medium. The storage stability of the liquid can be made more excellent.

1.4. Applications The amphipathic polymer according to this embodiment can be used as a dispersant for dispersing solid particles such as inorganic particles and organic particles in an aqueous medium. The inorganic particles are not particularly limited, and examples thereof include inorganic oxide particles such as silica, titania, and alumina. Examples of the organic particles include coloring materials such as pigments and dyes, as well as organic particles having a hydrophobic surface. Among these, since it is possible to suppress the increase in viscosity or gelation due to the addition of the amphipathic polymer, it is particularly preferable to use it as a dispersant for coloring materials such as pigments and dyes used in water-based inkjet inks.

1.5. Action Effect According to the amphipathic polymer of the present embodiment, since one amphipathic unit has both a hydrophilic group and a hydrophobic group, the hydrophilic monomer and the hydrophobic monomer were copolymerized. It is possible to obtain a dispersion liquid of a coloring material having higher dispersion stability as compared with a polymer. Further, according to the amphipathic polymer of the present embodiment, since it has a reactive unit, it is possible to obtain a water-based inkjet ink composition for printing having good fastness.

2. Color Material Dispersion Liquid Next, the color material dispersion liquid according to the embodiment of the present invention will be described.

The color material dispersion liquid according to the present embodiment contains a color material, an aqueous medium, and the above-mentioned amphipathic polymer. Since the color material dispersion liquid according to the present embodiment contains the above-mentioned amphipathic polymer, it is excellent in dispersion stability and storage stability of the color material, and is frictionally robust in a recording medium or the like to which the color material dispersion liquid is attached. The sex can be improved.

In the present specification, the color material dispersion liquid refers to a liquid in which the color material is dispersed in a dispersion medium, and is a concept including, for example, a stock solution used for producing an aqueous inkjet ink composition described later.

<Color material>
Examples of the coloring material include various pigments and various disperse dyes. Such a coloring material is generally highly hydrophobic, and when the above-mentioned amphipathic polymer is applied, it is excellent in adhesion to the hydrophobic group of the amphipathic unit of the amphipathic polymer. Therefore, the above-mentioned effects are exhibited.

Examples of the pigment include black pigments such as carbon black; C.I. I. Pigment Blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, C.I. I. Cyan pigments such as Bat Blue 4, 60; C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, C.I. I. Magenta pigments such as Pigment Violet 19; C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 150, 151, Yellow pigments such as 154, 155, 180, 185; C.I. I. Pigment Orange 36, 43 and other orange pigments; C.I. I. Examples thereof include green pigments such as Pigment Green 7 and 36.

Examples of the disperse dye include C.I. I. Disperse Yellow 3, 7, 8, 23, 39, 51, 54, 60, 71, 86; C.I. I. Disperse Orange 1, 1: 1, 5, 20, 25, 25: 1, 33, 56, 76; C.I. I. Disperse Brown 2; C.I. I. Disperse Red 11, 50, 53, 55, 55: 1, 59, 60, 65, 70, 75, 93, 146, 158, 190, 190: 1, 207, 239, 240; C.I. I. Bat Red 41; C.I. I. Disperse Violet 8, 17, 23, 27, 28, 29, 36, 57; C.I. I. Disperse Blue 19, 26, 26: 1, 35, 55, 56, 58, 64, 64: 1, 72, 72: 1, 81, 81: 1, 91, 95, 108, 131, 141, 145, 359 C. I. Examples thereof include Solvent Blue 36, 63, 105 and 111.

The color material dispersion liquid according to the present embodiment may contain a plurality of types of color materials.

The lower limit of the content of the coloring material in the coloring material dispersion liquid according to the present embodiment is preferably 0.2% by mass, more preferably 0.3% by mass, and particularly preferably 0.5% by mass. be. The upper limit of the content of the coloring material in the coloring material dispersion liquid according to the present embodiment is preferably 30% by mass, more preferably 25% by mass, and particularly preferably 20% by mass.

When the content of the coloring material is within the above range, more excellent color developing property can be obtained, and the dispersion stability of the coloring material and the storage stability of the coloring material dispersion liquid in the coloring material dispersion liquid are further improved. Further, when an ink jet ink is produced using this color material dispersion liquid, particularly excellent ejection stability can be obtained.

<Aphiphile polymer>
The color material dispersion liquid according to the present embodiment contains the above-mentioned amphipathic polymer. As a result, the above-mentioned effect can be obtained. The color material dispersion liquid according to the present embodiment may contain a plurality of types of amphipathic polymers.

The lower limit of the content of the amphipathic polymer in the colorant dispersion according to the present embodiment is preferably 0.2% by mass, more preferably 0.3% by mass, and particularly preferably 0.4. It is mass%. The upper limit of the content of the amphipathic polymer in the colorant dispersion liquid according to the present embodiment is preferably 30% by mass, more preferably 20% by mass, and particularly preferably 15% by mass. ..

When the content of the amphoteric polymer in the color material dispersion liquid according to the present embodiment is within the above range, the dispersion stability of the color material and the storage stability of the color material dispersion liquid in the color material dispersion liquid are further improved. improves. Further, when this color material dispersion liquid is applied to a water-based inkjet ink composition described later, the ejection stability by the inkjet method can be further improved.

When the content of the coloring material in the color material dispersion liquid according to the present embodiment is XD [mass%] and the content of the amphipathic polymer is XB [mass%], the lower limit of XB / XD is preferable. Is 0.3, more preferably 0.5, and particularly preferably 0.6. The upper limit of XB / XD is preferably 2.0, more preferably 1.5, and particularly preferably 1.2.

By satisfying such a relationship, the dispersion stability of the coloring material and the storage stability of the coloring material dispersion liquid are further improved. Further, when the color material dispersion liquid is applied to a water-based inkjet ink composition described later, the ejection stability by the inkjet method can be further improved.

<Aqueous medium>
The color material dispersion liquid according to the present embodiment contains an aqueous medium. Examples of the aqueous medium include a mixed medium of water, water and a water-soluble solvent. The water-soluble solvent refers to a solvent having a solubility in water at 25 ° C. of 10 g / 100 g or more.

The lower limit of the water content in the colorant dispersion liquid according to the present embodiment is not particularly limited, but is preferably 30% by mass, more preferably 35% by mass, and particularly preferably 40% by mass. The upper limit of the water content in the colorant dispersion liquid according to the present embodiment is not particularly limited, but is preferably 85% by mass, more preferably 80% by mass, and particularly preferably 75% by mass. be. Thereby, the viscosity of the color material dispersion liquid can be more reliably adjusted to a suitable value.

Further, since the color material dispersion liquid according to the present embodiment contains a water-soluble solvent as a solvent other than water, the viscosity of the color material dispersion liquid can be suitably adjusted. In addition, the moisturizing property of the color material dispersion liquid can be enhanced. As a result, when the color material dispersion liquid is applied to an water-based inkjet ink composition, particularly an inkjet water-based inkjet ink composition, droplet ejection by the inkjet method can be performed more stably.

The water-soluble solvent is a liquid substance by itself at room temperature (25 ° C.), and the lower limit of its standard boiling point is preferably 180 ° C., more preferably 185 ° C., and particularly preferably 190 ° C. The upper limit of the standard boiling point of the water-soluble solvent is preferably 320 ° C., more preferably 310 ° C., and particularly preferably 300 ° C.

Examples of such a water-soluble solvent include glycerin, propylene glycol, 2-pyrrolidone and the like. By containing these water-soluble solvents, the evaporation rate can be slowed down due to the excellent moisturizing ability, and more stable droplets can be obtained in the water-based inkjet ink composition to which the color material dispersion liquid according to the present embodiment is applied. Discharge can be performed. The color material dispersion liquid according to the present embodiment may contain a plurality of types of solvents as the water-soluble solvent.

The lower limit of the content of the water-soluble solvent in the colorant dispersion liquid according to the present embodiment is preferably 0% by mass, more preferably 10% by mass, and particularly preferably 15% by mass. The upper limit of the content of the water-soluble solvent in the color material dispersion liquid according to the present embodiment is preferably 45% by mass, more preferably 43% by mass, and particularly preferably 40% by mass. As a result, the effect of containing the above-mentioned hydrophilic solvent is more remarkable.

<Surfactant>
The color material dispersion liquid according to the present embodiment may contain a surfactant. Thereby, the wettability of the color material dispersion liquid and the water-based inkjet ink composition to which the color material dispersion liquid is applied to the recording medium can be made more suitable. As a result, for example, the image quality of the image formed by using the water-based inkjet ink composition can be improved.

As such a surfactant, for example, various surfactants such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used. More specifically, such surfactants include acetylene-based surfactants, silicone-based surfactants, fluorine-based surfactants, and the like.

When the color material dispersion liquid according to the present embodiment contains a silicone-based surfactant, the wettability of the color material dispersion liquid and the water-based inkjet ink composition to which the color material dispersion liquid is applied can be made more suitable for the recording medium. It is possible, and the above-mentioned effect is more prominently exhibited.

When the coloring material dispersion liquid according to the present embodiment contains a silicone-based surfactant, the lower limit of the content of the silicone-based surfactant is preferably 5.0 parts by mass with respect to 100 parts by mass of the coloring material. It is more preferably 7.0 parts by mass, and particularly preferably 10 parts by mass. The upper limit of the content of the silicone-based surfactant is preferably 150 parts by mass, more preferably 140 parts by mass, and particularly preferably 70 parts by mass with respect to 100 parts by mass of the coloring material. As a result, the effect of containing the above-mentioned silicone-based surfactant is more prominently exhibited.

Examples of commercially available silicone-based surfactants include BYK-306, BYK-307, BYK-333, BYK-337, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, BYK-. 349, BYK-378 (trade name, manufactured by Big Chemie Japan), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-640, KF-642, KF -643, KF-945, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned.

<Other ingredients>
The color material dispersion liquid according to the present embodiment may contain components other than the above-mentioned components. Examples of other components include dispersants other than the amphoteric polymer, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, diethylene glycol monomethyl ether, 1,2-hexanediol, 1,2-pentanediol, and 1, , 2-butanediol, 3-methyl 1,5-pentanediol and other penetrants, pH adjuster, ethylenediamine tetraacetate (EDTA) and other chelating agents, preservatives / fungicides, rust preventives, oxidation suppressors Agents, UV absorbers, oxygen absorbers, solubilizers, ureas and the like can be mentioned. As the preservative / fungicide, for example, a compound having an isothiazolin ring structure in the molecule can be preferably used.

The lower limit of the viscosity of the color material dispersion liquid according to the present embodiment at 25 ° C. is preferably 2 mPa · s, more preferably 3 mPa · s, and particularly preferably 4 mPa · s. The upper limit of the viscosity of the color material dispersion liquid according to the present embodiment at 25 ° C. is preferably 30 mPa · s, more preferably 20 mPa · s, and particularly preferably 15 mPa · s. As a result, the fluidity of the color material dispersion liquid can be made appropriately excellent. Further, in the water-based inkjet ink composition to which the color material dispersion liquid according to the present embodiment is applied, it is easy to adjust the ejection stability by the inkjet method so as to be good.

The viscosity is determined by reading the viscosity when the ^{shear rate is 10 [s-1} ] at 25 ° C. using a viscoelasticity tester (for example, MCR-300 manufactured by Pysica). Can be measured.

3. 3. Water-based inkjet ink composition Next, the water-based inkjet ink composition according to the embodiment of the present invention will be described. The water-based inkjet ink composition of the present embodiment is suitable for inkjet recording applications.

The water-based inkjet ink composition according to the present embodiment contains the above-mentioned color material dispersion liquid. Thereby, it is possible to provide an aqueous inkjet ink composition which is excellent in dispersion stability and storage stability of a coloring material and in which high viscosity or gelation is suppressed.

The water-based inkjet ink composition according to the present embodiment may be a water-based inkjet ink composition obtained by using the above-mentioned color material dispersion as it is, or the above-mentioned color material dispersion may be mixed with a diluting solvent or the like. It may be prepared by adding components, or it may be prepared by mixing two or more kinds of the above-mentioned color material dispersions.

The water-based inkjet ink composition according to the present embodiment is a water-based ink composition, and is particularly preferably an water-based inkjet ink composition.

Since the water-based inkjet ink composition according to the present embodiment is excellent in dispersion stability and storage stability of the coloring material, unintentional aggregation and sedimentation of the coloring material are effective even when stored for a long period of time. Can be suppressed. As a result, even when ejection is performed by the inkjet method, ejection defects and the like are unlikely to occur. Therefore, when the present invention is applied to an inkjet application, the effect of the present invention is more prominently exhibited. The water-based inkjet ink composition according to the present embodiment may contain a plurality of types of amphipathic polymers.

The lower limit of the content of the amphipathic polymer in the water-based inkjet ink composition according to the present embodiment is preferably 0.1% by mass, more preferably 0.2% by mass, and particularly preferably 0. 4% by mass. The upper limit of the content of the amphipathic polymer is preferably 30% by mass, more preferably 18% by mass, and particularly preferably 10% by mass. When the content of the amphipathic polymer is within the above range, the dispersion stability of the coloring material in the water-based inkjet ink composition and the storage stability of the water-based inkjet ink composition are further improved. Further, when this water-based inkjet ink composition is used as an inkjet ink, particularly excellent ejection stability can be obtained.

The lower limit of the content of the coloring material in the water-based inkjet ink composition according to the present embodiment is preferably 0.1% by mass, more preferably 0.3% by mass, and particularly preferably 0.5% by mass. Is. The upper limit of the content of the coloring material is preferably 30% by mass, more preferably 15% by mass, and particularly preferably 8.0% by mass. When the content of the color material is within the above range, more excellent color development property can be obtained, and the dispersion stability of the color material and the storage stability of the ink in the water-based inkjet ink composition are further improved. Further, when this water-based inkjet ink composition is used as an inkjet ink composition, particularly excellent ejection stability can be obtained.

When the content of the coloring material in the water-based inkjet ink composition is XD [mass%] and the content of the amphipathic polymer is XB [mass%], 0.3 ≦ XB / XD ≦ 2.0. It is preferable to satisfy the relationship, more preferably 0.5 ≦ XB / XD ≦ 1.5, and even more preferably 0.6 ≦ XB / XD ≦ 1.2. By satisfying such a relationship, the dispersion stability of the coloring material and the storage stability of the water-based inkjet ink composition are further improved. Further, when this water-based inkjet ink composition is used as an inkjet ink, particularly excellent ejection stability can be obtained.

<Aqueous medium>
The water-based inkjet ink composition according to the present embodiment contains an water-based medium. Examples of the aqueous medium include a mixed medium of water, water and a water-soluble solvent. As the water-soluble solvent, those described as the constituent components of the color material dispersion liquid can be preferably used.

The lower limit of the water content in the water-based inkjet ink composition according to the present embodiment is not particularly limited, but is preferably 40% by mass, more preferably 45% by mass, and particularly preferably 50% by mass. .. The upper limit of the water content is not particularly limited, but is preferably 85% by mass, more preferably 80% by mass, and particularly preferably 75% by mass. Thereby, the viscosity of the water-based inkjet ink composition can be more reliably adjusted to a suitable value. Further, when this water-based inkjet ink composition is used for inkjet, particularly excellent ejection stability can be obtained. In addition, good frictional robustness of the image on the recording medium can be obtained.

The lower limit of the content of the water-soluble solvent in the water-based inkjet ink composition according to the present embodiment is preferably 0% by mass, more preferably 10% by mass, and particularly preferably 15% by mass. The upper limit of the content of the water-soluble solvent is preferably 45% by mass, more preferably 43% by mass, and particularly preferably 40% by mass. As a result, the effect of containing the above-mentioned water-soluble solvent is more remarkable.

<Surfactant>
The water-based inkjet ink composition according to the present embodiment may contain a surfactant. Thereby, the wettability of the water-based inkjet ink composition with respect to the recording medium can be made more suitable. As a result, for example, the image quality of the image formed by using the water-based inkjet ink composition can be improved.

As the surfactant, those described as constituents of the colorant dispersion liquid can be preferably used. As a result, the same effect as described above can be obtained.

When the water-based inkjet ink composition according to the present embodiment contains a silicone-based surfactant, the lower limit of the content of the silicone-based surfactant in the water-based inkjet ink composition is 100 parts by mass of the coloring material. , It is preferably 5.0 parts by mass, more preferably 7.0 parts by mass, and particularly preferably 10 parts by mass. The upper limit of the content of the silicone-based surfactant in the water-based inkjet ink composition is preferably 150 parts by mass, more preferably 140 parts by mass, and particularly preferably 140 parts by mass with respect to 100 parts by mass of the coloring material. Is 70 parts by mass. As a result, the effect of containing the above-mentioned silicone-based surfactant is more prominently exhibited.

<Other ingredients>
The water-based inkjet ink composition according to the present embodiment may contain components other than those described above. As the other components, for example, those described as the constituent components of the color material dispersion liquid can be preferably used.

The lower limit of the surface tension of the water-based inkjet ink composition according to the present embodiment at 25 ° C. is preferably 20 mN / m, more preferably 21 mN / m, and particularly preferably 23 mN / m. The upper limit of surface tension is preferably 50 mN / m, more preferably 40 mN / m, and particularly preferably 30 mN / m. As a result, clogging of the nozzle of the droplet ejection head is less likely to occur, and the ejection stability of the water-based inkjet ink composition is further improved. Further, even when the nozzle is clogged, the recovery by capping the nozzle (capping) can be made more excellent.

As the surface tension, a value measured by the Wilhelmy method can be adopted. A surface tension meter (for example, manufactured by Kyowa Interface Science Co., Ltd., CBVP-7, etc.) can be used for measuring the surface tension.

The lower limit of the viscosity of the water-based inkjet ink composition according to the present embodiment at 25 ° C. is preferably 2 mPa · s, more preferably 3 mPa · s, and particularly preferably 4 mPa · s. The upper limit of the viscosity is preferably 10 mPa · s, more preferably 8 mPa · s, and particularly preferably 6 mPa · s. Thereby, the fluidity of the water-based inkjet ink composition can be made appropriately excellent. Further, when the water-based inkjet ink composition according to the present embodiment is used for inkjet, particularly excellent ejection stability can be obtained.

The water-based inkjet ink composition according to the present embodiment is usually applied to various recording devices, for example, a recording device by the inkjet method, in a state of being stored in a container such as a cartridge, a bag, or a tank.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto.

For example, in the above-described embodiment, the case where the above-mentioned color material dispersion liquid is used as the water-based inkjet ink composition or its stock solution has been mainly described, but the use of the above-mentioned color material dispersion liquid is not limited thereto. For example, it may be used as a paint.

4. Examples Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples. Hereinafter, "%" is based on mass unless otherwise specified.

4.1. Synthesis of amphipathic polymer (Examples 1 to 9) Synthesis of linear amphipathic polymer Monomer containing block isocyanate, initiator and AIBN (azobisisobutyronitrile) in a molar ratio of 500/7 / It was dissolved in benzene so as to be 0.2. The reaction was stopped by heating the solution at 60 ° C. for 30 hours and storing it in a freezer at −20 ° C. for 5 minutes. The reaction solution was dissolved in anhydrous THF (tetrahydrofuran), and methanol and Me ₃ SiTeMe were added to replace the terminal organic tellurium with hydrogen. The solution was stirred for 1 hour at room temperature and precipitated in hexane. The obtained solid was separated by centrifugation and dried in vacuum.

(Examples 10 to 18) Synthesis of branched amphipathic polymer A monomer containing a blocked isocyanate, an initiator, a branching agent and AIBN (azobisisobutyronitrile) are mixed in a molar ratio of 500/7/1 / 0.2. It was dissolved in benzene so as to become. The reaction was stopped by heating the solution at 60 ° C. for 30 hours and storing it in a freezer at −20 ° C. for 5 minutes. The reaction solution was dissolved in anhydrous THF (tetrahydrofuran), and methanol and Me ₃ SiTeMe were added to replace the terminal organic tellurium with hydrogen. The solution was stirred for 1 hour at room temperature and precipitated in hexane. The obtained solid was separated by centrifugation and dried in vacuum.

(Comparison example)
As the amphipathic polymer of the comparative example, it was the same as the other examples except that a block copolymer of "MS-10B" styrene-methyl methacrylate manufactured by NOF CORPORATION was used. The number average molecular weight is 197,000.

4.2. Preparation of varnish solution The above-mentioned ionized polymer (1.67 g) was added to a mixture of pure water (9.53 g) and triethanolamine (1.43 g) and heated at 120 ° C. for 10 hours (120 ° C., 10 hours).

4.3. Preparation of Coloring Material Dispersion Solution Pure water (9.45 g) was added to the varnish solution (13.5 g) to dilute it. Next, P.I. B. 15: 3 (CI Pigment Blue 15: 3) (4.05 g) and zirconia beads (81 g) were added to a resin cup, and the varnish solution was further added. After stirring with a defoaming stirrer, the beads were separated by filtration, and P.I. B. A 15: 3 dispersion was obtained.

4.4. Preparation of Aqueous Inkjet Ink Composition The above dispersion and the components shown in Tables 1 and 2 were mixed in the amounts shown in Table 1 to obtain a PB15: 3 aqueous inkjet ink composition (Examples 1 to 18). , Comparative example).

The abbreviations in Tables 1 and 2 are as follows.
・ P. B. 15: 3; C.I. I. Pigment Blue 15: 3
-OBu: Butoxy-OPh: Phenoxy-CH: Cyclohexyl-SO4: Sulfonic acid-EO: Oxyethylene-COO: Carboxylic acid-4VP: 4-vinylpyridine-BYK-348: Silicone-based surfactant manufactured by Big Chemie Japan Co., Ltd. Agent In the table, the "hydrophobic group" represents the "X" of the above formula (2), and the "hydrophilic group" represents the structure contained in the "Y" of the above formula (2).
Further, in Examples 10 to 18, the amphipathic polymer has a branched structure, and the number of branched generations is 3.

4.5. Evaluation Method The following tests were performed on the water-based inkjet ink compositions of each example.

4.5.1. Particle size distribution and its change The average particle size (D50) of the dispersion was determined for the water-based inkjet ink composition immediately after production obtained above. Then, for the water-based inkjet ink composition left in an environment of 60 ° C. for 5 days, the average particle size (D50) of the dispersion was determined, and the rate of increase in the average particle size was determined. The results of evaluation according to the following evaluation criteria are shown in Tables 1 and 2.
<Particle size distribution>
A: D50 is 100 nm or less B: D50 is more than 100 nm and 300 nm or less C: D50 is more than 300 nm <Change in particle size distribution>
A: Increase in D50 is less than 10% B: Increase in D50 is 10% or more and less than 30% C: Increase in D50 is 30% or more

4.5.2. Continuous ejection stability The water-based inkjet ink compositions of the respective Examples and Comparative Examples were each filled in a predetermined ink container and left to stand in an environment of 60 ° C. for 5 days. After that, the storage container is attached to a recording device PX-H6000 (manufactured by Seiko Epson), inkjet ink is ejected, and 100,000 shots are made to TRANSJET Classic (manufactured by Cham Paper), which is an intermediate transfer medium, with 100 nozzles. The number of nozzle clogging during continuous ejection was investigated and evaluated according to the following criteria. It can be said that the smaller the number of nozzle clogging, the better the discharge stability. The operating environment of the recording device (printer) was set to 40 ° C. and 20 RH%.
The results of evaluation according to the following evaluation criteria are shown in Tables 1 and 2.
A: 100,000 nozzles continuously discharge 100,000 shots, that is, none B: 100 nozzles continuously discharge 100,000 shots, that is, within 10 C: 100 nozzles continuously discharge 100,000 shots, that is, 10 or more

4.5.3. Viscosity For the inks immediately after production of each of the above Examples and Comparative Examples, shearing at a shear rate of 10 [s- ¹ ] in an environment of 25 ° C. using a viscoelasticity tester (MCR-300, manufactured by Pysica). The viscosity was determined and evaluated according to the following criteria. If the viscosity is high, the ejection stability of the inkjet is lowered and the head is clogged.
The results of evaluation according to the following evaluation criteria are shown in Tables 1 and 2.
A: The viscosity at a shear rate of 10 (1 / s) is 5 ± 1 mPa · s.
B: Viscosity at shear rate 10 (1 / s) exceeds 5 mPa · s and is 10 mPa · s or less C: Viscosity at shear rate 10 (1 / s) exceeds 10 mPa · s

4.5.4. Friction fastness test As an index of ink fastness (pigment fixability) against scratches, a friction tester type 2 (Gakushin type tester) is used in accordance with JIS L 0849 (dyeing fastness test method against friction). The friction fastness test was performed. Specifically, first, the following recording medium 1 to the recording medium 4 were cut into A4 size and attached to high-quality paper (manufactured by Hokuetsu Kishu Paper Co., Ltd.) with double-sided tape. This is a countermeasure for the possibility of transport defects when cloth is used for an inkjet printer that uses paper or the like as a recording medium. The recording medium 1 and the recording medium 2 contain cellulose, and the recording medium 3 and the recording medium 4 do not contain cellulose.
Recording medium 1: Cotton cloth (manufactured by Hokuetsu Kishu Paper Co., Ltd.)
Recording medium 2: Linen cloth (manufactured by Takemi Cross)
Recording medium 3: Polyester fabric (Cosmo Textile Co., Ltd.)
Recording medium 4: Silk handkerchief (Abasa)

Next, solid printing was performed on each recording medium under the same conditions as in the pressure resistance test. Then, the woodfree paper and the double-sided tape were peeled off and heated at 145 ° C. for 10 minutes to prepare a sample. A friction fastness test was performed using this sample and evaluated according to the following criteria, and the results are shown in Tables 1 and 2.
A: 4-5 grade to 5 grade B: 2-3 grade to 4 grade C: 1-2 grade D: less than 1-2 grade

4.6. Evaluation Results The aqueous inkjet ink composition of each example, which comprises a polymer dispersant having an amphipathic unit containing a hydrophilic group and a hydrophobic group and a reactive unit containing a reactive group, has one parent. Since the medial unit has both a hydrophilic group and a hydrophobic group, it has higher dispersion stability as compared with a polymer (comparative example) in which a hydrophilic monomer and a hydrophobic monomer are copolymerized. I found out. In addition, the water-based inkjet ink compositions of each example contained an amphipathic polymer having a reactive unit, and as a result, printing with good friction fastness could be performed.

The above-described embodiments and modifications are merely examples, and the present invention is not limited thereto. For example, each embodiment and each modification can be combined as appropriate.

The present invention includes a configuration substantially the same as the configuration described in the embodiment, for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect. The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

The following contents are derived from the above-described embodiments and modifications.

One aspect of amphipathic polymers is
An amphipathic unit containing hydrophilic and hydrophobic groups,
Reactive units containing reactive groups and
Have.

According to this amphipathic polymer, since one amphipathic unit has both a hydrophilic group and a hydrophobic group, it is compared with a polymer obtained by copolymerizing a hydrophilic monomer and a hydrophobic monomer. Therefore, a dispersion liquid of a coloring material having higher dispersion stability can be obtained. Further, according to this amphipathic polymer, since it has a reactive unit, it is possible to obtain an ink composition for printing having good fastness.

（式（１）中、Ｘは、直鎖状、分岐状若しくは環構造を含む炭素数３以上のアルキル基、直鎖状、分岐状若しくは環構造を含む炭素数３以上のアルコキシ基、フェニル基、フェノキシ基、又は、フェノキシメチル基を表し、Ｙは、−ＯＲ、−Ｏ（ＣＨ_２ＣＨ_２Ｏ）_ｐ−ＣＨ_２ＣＨ_３、−（ＯＣＨ_２ＣＨ_２）_ｐＳＯ_３Ｈ、−（ＯＣＨ_２ＣＨ_２）_ｐＣＯ_２Ｈ、−（ＯＣＨ_２ＣＨ_２）_ｐＰＯ_４Ｈ_２、−Ｏ（ＣＨ_２ＣＨ_２Ｏ）_ｐＨ、−Ｏ（ＣＨ_２）_ｑＯＨで表されるいずれかの基を表し、Ｒは、水素、又は、直鎖状、分岐状若しくは環状の炭素数１以上６以下のアルキル基を表し、ｐは１以上６以下の整数を表し、ｑは２以上８以下の整数を表す。） In the aspect of the amphipathic polymer,
The amphipathic unit may contain a structure derived from a monomer unit represented by the following formula (1).

(In the formula (1), X is an alkyl group having 3 or more carbon atoms including a linear, branched or ring structure, an alkoxy group having 3 or more carbon atoms including a linear, branched or ring structure, and a phenyl group. , Phenoxy group, or phenoxymethyl group, where Y is -OR, -O (CH ₂ CH ₂ O) _p -CH ₂ CH ₃ ,-(OCH ₂ CH ₂ ) _p SO ₃ H,-(OCH ₂₎ CH ₂ ) _p CO ₂ H,-(OCH ₂ CH ₂ ) _p PO ₄ H ₂ , -O (CH ₂ CH ₂ O) _p H, -O (CH ₂ ) _q OH R represents hydrogen or a linear, branched or cyclic alkyl group having 1 or more and 6 or less carbon atoms, p represents an integer of 1 or more and 6 or less, and q represents an integer of 2 or more and 8 or less. show.)

According to this amphipathic polymer, hydrophilic groups and hydrophobic groups can be easily introduced into one amphipathic unit.

In the aspect of the amphipathic polymer,
A group in which the hydrophilic group contains a structure selected from an oligooxyethylene chain, a carboxyl group, a hydroxyalkyl group, a sulfonic acid group, a phosphoric acid group, an alkyl carboxylate group, and an ester group of a carboxylic acid and an alkylene diol. It may be included.

According to this amphipathic polymer, hydrophilic groups and hydrophobic groups can be easily introduced into one amphipathic unit.

In the aspect of the amphipathic polymer,
The hydrophobic group may include a group selected from a cyclohexyl group, a phenoxy group, and a phenoxymethyl group.

According to this amphipathic polymer, hydrophilic groups and hydrophobic groups can be easily introduced into one amphipathic unit.

In the aspect of the amphipathic polymer,
The reactive group may be a blocked isocyanate group.

According to this amphipathic polymer, reactive groups can be stably stored.

In the aspect of the amphipathic polymer,
It may have a branched structure.

According to this amphipathic polymer, it is easy to be adsorbed to the dispersible coloring material in a mesh pattern, and the dispersion stability can be further improved. Further, the viscosity of the color material dispersion liquid or the water-based inkjet ink composition can be further lowered.

One aspect of the color material dispersion liquid according to the present invention is
With the amphipathic polymer of any of the above embodiments,
Dispersible color material and
including.

Since the color material dispersion liquid contains the amphipathic polymer, it is possible to achieve a highly stable dispersion.

One aspect of the water-based inkjet ink composition according to the present invention is
The color material dispersion liquid of the above aspect is contained.

According to this water-based inkjet ink composition, since the amphipathic polymer is contained, good dispersibility of the dispersible coloring material can be obtained.

Claims (8)

An amphipathic unit containing hydrophilic and hydrophobic groups,
Reactive units containing reactive groups and
An amphipathic polymer having. In claim 1,
The amphipathic unit is an amphipathic polymer containing a structure derived from a monomer unit represented by the following formula (1).

(In the formula (1), X is an alkyl group having 3 or more carbon atoms including a linear, branched or ring structure, an alkoxy group having 3 or more carbon atoms including a linear, branched or ring structure, and a phenyl group. , Phenoxy group, or phenoxymethyl group, where Y is -OR, -O (CH ₂ CH ₂ O) _p -CH ₂ CH ₃ ,-(OCH ₂ CH ₂ ) _p SO ₃ H,-(OCH ₂₎ CH ₂ ) _p CO ₂ H,-(OCH ₂ CH ₂ ) _p PO ₄ H ₂ , -O (CH ₂ CH ₂ O) _p H, -O (CH ₂ ) _q OH R represents hydrogen or a linear, branched or cyclic alkyl group having 1 or more and 6 or less carbon atoms, p represents an integer of 1 or more and 6 or less, and q represents an integer of 2 or more and 8 or less. show.) In claim 1 or 2,
A group in which the hydrophilic group contains a structure selected from an oligooxyethylene chain, a carboxyl group, a hydroxyalkyl group, a sulfonic acid group, a phosphoric acid group, an alkyl carboxylate group, and an ester group of a carboxylic acid and an alkylene diol. Including, parental polymer. In any one of claims 1 to 3,
An amphipathic polymer in which the hydrophobic group contains a group selected from a cyclohexyl group, a phenoxy group, and a phenoxymethyl group. In any one of claims 1 to 4,
The reactive group is an amphipathic polymer which is a blocked isocyanate group. In any one of claims 1 to 5,
An amphipathic polymer with a branched structure. The amphipathic polymer according to claims 1 to 6,
Water-insoluble coloring material and
Color material dispersion, including. A water-based inkjet ink composition containing the color material dispersion liquid according to claim 7.