JP6687898B2 - Ink and its manufacturing method, ink container, ink jet recording method, ink jet recording apparatus, and recorded matter - Google Patents

Description

  The present invention relates to an ink, a method for manufacturing the same, an ink container, an inkjet recording method, an inkjet recording device, and a recorded matter.

  The inkjet recording method is popular because it has an advantage that the process is simpler than other recording methods, full colorization is easy, and a high-resolution image can be obtained even with an apparatus having a simple structure. It is expanding from personal to office applications, commercial printing and industrial printing. In such an ink jet recording method, an aqueous ink composition using a water-soluble dye as a coloring material is mainly used, but since it has a drawback of poor water resistance and light resistance, a water-insoluble alternative to the water-soluble dye is used. The development of pigment inks using these pigments is in progress.

  In inkjet printing for office use, plain paper is mainly used as a recording medium, and high image density is required. Generally, when a pigment ink is printed on plain paper, the pigment penetrates into the paper without staying on the paper surface, so that the pigment density on the paper surface becomes low and the image density decreases. The higher the pigment concentration in the ink, the higher the image density, but the viscosity of the ink increases and the ejection stability decreases.

  Further, in the fields of commercial printing and industrial printing, there is a need for a technique capable of stably producing an image with higher resolution and higher definition at a higher speed. As the recording medium, plain paper, coated paper, art paper, non-permeable film such as PET film and the like are used, and high compatibility of ink with the recording medium is required. In the ink jet recording system, to prevent paper curl that occurs when printing on plain paper, or when printing on coated paper or art paper, increase ink permeability to speed up drying and prevent beading. In order to achieve this, there is a method of adding a hydrophilic organic solvent to the aqueous ink.

  Further, the water-based pigment ink used in the inkjet recording system or the writing instrument, unlike the water-based dye ink prepared by dissolving the dye in water, needs to stably disperse the water-insoluble pigment in the water for a long period of time. , Various pigment dispersants have been developed. For example, a graft polymer having an aromatic ring in its side chain has been proposed (see, for example, Patent Document 1).

  It is an object of the present invention to provide an ink having a high storage stability and high image density even when recorded on plain paper.

ただし、前記一般式（１）中、Ｒ₁は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（２）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。 The ink of the present invention as a means for solving the above problems is an ink containing water, a coloring material, and a copolymer, and the copolymer is represented by the following general formula (1). A structural unit and a structural unit represented by the following general formula (2) are included.

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.

  According to the present invention, it is possible to provide an ink having a high storage stability and a high image density even when recorded on plain paper.

FIG. 1 is a perspective explanatory view showing an example of an inkjet recording apparatus. FIG. 2 is a perspective explanatory view showing an example of a main tank in the inkjet recording apparatus.

ただし、前記一般式（１）中、Ｒ₁は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（２）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。
［２］前記一般式（２）で表される構造単位が、下記一般式（３）で表される構造単位である前記［１］に記載のインク。

ただし、前記一般式（３）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０の整数を表す。
［３］前記一般式（１）で表される構造単位の、前記共重合体における含有率が４０質量％以上７０質量％以下である前記［１］または［２］に記載のインク。
［４］前記共重合体の重量平均分子量が、１５，０００〜４０，０００である前記［１］から［３］のいずれかに記載のインク。
［５］前記色材が、顔料である前記［１］から［４］のいずれかに記載のインク。
［６］有機溶剤、及び界面活性剤の少なくともいずれかを更に含有する前記［１］から［５］のいずれかに記載のインク。
［７］前記インクがインクジェット用インクである前記［１］から［６］のいずれかに記載のインク。
［８］水、色材、及び共重合体を含有するインクの製造方法であって、
前記共重合体が、下記一般式（４）で表されるモノマー、及び下記一般式（５）で表されるモノマーを含む重合性材料からラジカル重合により合成される工程を含むインクの製造方法。

ただし、前記一般式（４）中、Ｒ₄は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（５）中、Ｒ₅及びＲ₆は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。
［９］インクを収容するインク収容部を備えたインク収容容器であって、前記インク収容部に収容されたインクが、前記［１］から［７］のいずれかに記載のインクであるインク収容容器。
［１０］前記［１］から［７］のいずれかに記載のインクに刺激を印加し、前記インクを吐出させて画像を記録するインク吐出工程を含むインクジェット記録方法。
［１１］前記［１］から［７］のいずれかに記載のインクに刺激を印加し、前記インクを吐出させて画像を記録するインク吐出手段を有するインクジェット記録装置。
［１２］記録媒体上に記録層を有する記録物であって、
前記記録層が、色材、及び、共重合体を含み、
前記共重合体が、下記一般式（１）で表される構造単位及び下記一般式（２）で表される構造単位を含む記録物。

ただし、前記一般式（１）中、Ｒ₁は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（２）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。 Hereinafter, the present invention will be described in detail. The present invention relates to the following [1], but the following [2] to [12] are also included in the embodiment of the present invention, and therefore these will also be described.
[1] An ink containing water, a coloring material, and a copolymer,
An ink characterized in that the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.
[2] The ink according to the above [1], wherein the structural unit represented by the general formula (2) is a structural unit represented by the following general formula (3).

However, in the general formula (3), R ₂ and R ₃ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 90.
[3] The ink according to [1] or [2], wherein the content of the structural unit represented by the general formula (1) in the copolymer is 40% by mass or more and 70% by mass or less.
[4] The ink according to any one of [1] to [3], wherein the copolymer has a weight average molecular weight of 15,000 to 40,000.
[5] The ink according to any one of [1] to [4], wherein the color material is a pigment.
[6] The ink according to any one of [1] to [5], further containing at least one of an organic solvent and a surfactant.
[7] The ink according to any one of [1] to [6], wherein the ink is an inkjet ink.
[8] A method for producing an ink containing water, a coloring material, and a copolymer,
A method for producing an ink, comprising the step of synthesizing the copolymer by radical polymerization from a polymerizable material containing a monomer represented by the following general formula (4) and a monomer represented by the following general formula (5).

However, in the general formula (4), R ₄ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

In the general formula (5), R ₅ and R ₆ represent a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.
[9] An ink storage container including an ink storage portion that stores ink, wherein the ink stored in the ink storage portion is the ink according to any one of [1] to [7]. container.
[10] An inkjet recording method including an ink ejection step of applying a stimulus to the ink according to any one of [1] to [7] to eject the ink to record an image.
[11] An inkjet recording apparatus having an ink ejecting unit that applies a stimulus to the ink according to any one of [1] to [7] and ejects the ink to record an image.
[12] A recorded matter having a recording layer on a recording medium,
The recording layer contains a coloring material and a copolymer,
A recorded material, wherein the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.

(ink)
The ink of the present invention contains water, a coloring material, and the following copolymer, and further contains other components as necessary.
The ink of the present invention is based on the finding that long-term storage stability is insufficient when a conventional graft polymer is used as a pigment dispersant.

ただし、前記一般式（１）中、Ｒ₁は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（２）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。
ｎ及びｍは、エチレンオキサイド（Ｃ₂Ｈ₄Ｏ）及びプロピレンオキサイド（Ｃ₃Ｈ₆Ｏ）の平均付加モル数を表す。 <Copolymer>
The copolymer used in the ink of the present invention contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and further contains other structural units as necessary. It consists of

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.
n and m represent the average number of moles of ethylene oxide (C ₂ H ₄ O) and propylene oxide (C ₃ H ₆ O) added.

ただし、前記一般式（３）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０の整数を表す。
インクの保存安定性及び画像濃度の点から、前記一般式（２）において、ｎ＝４〜５０、ｍ＝０がより好ましく、ｎ＝８〜３０、ｍ＝０がさらに好ましい。 The structural unit represented by the general formula (2) is preferably a structural unit represented by the following general formula (3).

However, in the general formula (3), R ₂ and R ₃ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 90.
From the viewpoint of ink storage stability and image density, in the general formula (2), n = 4 to 50 and m = 0 are more preferable, and n = 8 to 30 and m = 0 are further preferable.

  In the structural unit represented by the general formula (1), the naphthyl group existing at one end via the alkylene group at the open end (open end, that is, the pendant structure portion) at the end is a coloring material in the ink. Due to the π-π stacking with the pigment that is

Specific examples of the structural unit represented by the general formula (1) are shown below, but the invention is not limited to the following specific examples.

As can be understood from the description of the above-mentioned “naphthyl group which is present at the terminal via the alkylene group in the pendant”, the structural unit represented by the general formula (1) is typically pendant via the alkylene group. The main chain of the copolymer may have a pendant group such as a terminal naphthyl group. However, of course, the case where a part is contained in the side chain is not excluded.
For example, it is a well known fact that it is difficult to completely eliminate the secondary radical polymerization reaction that produces a branched structure.
Further, when preparing the pigment dispersion in which the pigment is dispersed in water, when the copolymer used in the present invention is used, since a naphthyl group is present at the terminal of the side chain of the copolymer, the pigment surface is Since it is easily adsorbed and has a high adsorption power with respect to the pigment, a pigment dispersion having high dispersibility and stable for a long time can be obtained.

  The content of the structural unit represented by the general formula (1) is not particularly limited and can be appropriately selected depending on the purpose, but is 30% by mass or more and 80% by mass or less with respect to the total amount of the copolymer. % Or less, preferably 40% by mass or more and 70% by mass or less. When the content is within the preferable range, it is advantageous in that the image density and the storage stability are good when used in the ink.

  Cellulose, which mainly constitutes the structural unit represented by the general formula (2) and the plain paper, is hydrophilic. Therefore, it is considered that the structure represented by the general formula (2) has an affinity for cellulose rather than a hydrophobic solvent. When the copolymer is used in ink, the copolymer adsorbed on the pigment during printing is adsorbed on the cellulose, and the pigment easily stays on the paper surface. It is considered that, in the general formula (2), n has a polyethylene glycol chain and a polypropylene glycol chain of 0 to 90 and m is 0 to 90, so that it is easy to contact with cellulose and more easily adsorbed to cellulose. As a result, high image density can be exhibited even on plain paper.

  The content of the structural unit represented by the general formula (2) is not particularly limited and may be appropriately selected depending on the purpose, but is 20% by mass or more and 70% by mass or less with respect to the total amount of the copolymer. The following is preferable, and 30% by mass or more and 60% by mass or less is more preferable. When the content is within the preferable range, it is advantageous in that the image density and the storage stability are good when used in the ink.

The copolymer may have a repeating unit derived from another polymerizable monomer in addition to the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2).
The other polymerizable monomer is not particularly limited and may be appropriately selected depending on the purpose. For example, a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, a polymerizable surfactant and the like can be mentioned, but it is preferable that the polymerizable hydrophilic monomer does not include an ionic monomer. By not containing an ionic monomer, the storage stability of the ink and the image density tend to be good. Although the mechanism is not clear, when an ionic monomer is further contained in addition to the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2), it is represented by the general formula (2). The storability of the ink and the image density may be affected by the interaction between the structural unit and the ionic monomer.

  Examples of the polymerizable hydrophobic monomer include unsaturated ethylene monomers having an aromatic ring such as styrene, α-methylstyrene, 4-t-butylstyrene, and 4-chloromethylstyrene; methyl (meth) acrylate; Ethyl (meth) acrylate, -n-butyl (meth) acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, dodecyl (meth) acrylate (C12), tridecyl (meth) acrylate (C13), ( Tetradecyl (meth) acrylate (C14), pentadecyl (meth) acrylate (C15), hexadecyl (meth) acrylate (C16), heptadecyl (meth) acrylate (C17), nonadecyl (meth) acrylate (C19), ( Eicosyl acrylate (C20), henicosyl acrylate ( 21), alkyl (meth) acrylate such as docosyl (meth) acrylate (C22); 1-heptene, 3,3-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 3-methyl-1. -Hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-octene, 3,3-dimethyl-1-hexene, 3,4-dimethyl-1-hexene, 4,4-dimethyl-1 -Hexene, 1-nonene, 3,5,5-trimethyl-1-hexene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene , 1-octadecene, 1-nonadecene, 1-eicosene, 1-dococene, and the like, and unsaturated ethylene monomers having an alkyl group. These may be used alone or in combination of two or more.

Examples of the polymerizable hydrophilic monomer include 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone. And nonionic unsaturated ethylene monomers such as acrylamide, N, N-dimethylacrylamide, Nt-butylacrylamide, N-octylacrylamide, Nt-octylacrylamide and the like.
The polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer may be used alone or in combination of two or more.
The contents of the polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer are the same as those of the monomer forming the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). It is preferably 5% by mass or more and 100% by mass or less based on the total amount.

The polymerizable surfactant is an anionic or nonionic surfactant having at least one radically polymerizable unsaturated double bond group in the molecule.
Examples of the anionic surfactant, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ hydrocarbon compound having a sulfate group and an allyl group (-CH ₂ -CH = CH _2), such as, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate group and methacrylic group, such as _{[-CO-C (CH 3) =} CH 2 ] a hydrocarbon compound having, or ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate, such as base and 1 - an aromatic hydrocarbon compound having a propenyl group (-CH = CH ₂ CH ₃₎ and the like. Examples of the anionic surfactant include Eleminol JS-20 and RS-300 manufactured by Sanyo Kasei Co., Ltd., Aqualon KH-10, Aqualon KH-1025, and Aqualon KH-05 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. , Aqualon HS-10, Aqualon HS-1025, Aqualon BC-0515, Aqualon BC-10, Aqualon BC-1025, Aqualon BC-20, and Aqualon BC-2020.

Examples of the nonionic surface active agent, e.g., a 1-propenyl group (-CH = CH ₂ CH ₃₎ polyoxyethylene group _{[- (C 2 H 4 O)} n-H ] a hydrocarbon compound having a or Examples thereof include aromatic hydrocarbon compounds. Specific examples of the nonionic surfactants include Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, and Aqualon RN-50 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Latemur PD-produced by Kao Corporation. 104, latemuru PD-420, latemuru PD-430, latemuru PD-450, and the like.

The polymerizable surfactant may be used alone or in combination of two or more.
The content of the polymerizable surfactant is 0. 1 with respect to the total amount of the monomers forming the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). It is preferably 1% by mass or more and 10% by mass or less.

  The weight average molecular weight of the copolymer is preferably 5,000 to 50,000, more preferably 15,000 to 40,000 in terms of polystyrene. When the weight average molecular weight is within the preferable range, it is advantageous in that the image density and the storage stability are improved when used in the ink.

The structure of the copolymer can be analyzed by using a general analysis method such as NMR or IR.
Further, the molar ratio of the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) constituting the copolymer was used when synthesizing the copolymer. It can be determined by the molar ratio of the monomers. Further, it can be determined by NMR from the copolymer.

ただし、前記一般式（４）中、Ｒ₄は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。 <Method for synthesizing copolymer>
The copolymer containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) in the present invention is a compound represented by the following general formula (4) and the following general formula: It is preferably synthesized by radical polymerization from a polymerizable material (starting material) containing the compound represented by (5).

However, in the general formula (4), R ₄ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

ただし、前記一般式（５）中、Ｒ₅及びＲ₆は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。

In the general formula (5), R ₅ and R ₆ represent a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.

Specific examples of the compound represented by formula (4) are shown below, but the invention is not limited to the following specific examples.

  The compound represented by the general formula (4) can be synthesized as follows. That is, as shown in the following reaction formulas (1) and (2), first, a diol compound (A-1) and a naphthalene acetic acid (A-2) are reacted in the presence of an acid catalyst to give a reaction intermediate (A -3) is obtained. Then, 2-isocyanatoethyl (meth) acrylate (A-4) can be reacted with the (A-3) to obtain the monomer represented by the general formula (4).

ただし、前記反応式（１）中、Ｘは、前記一般式（４）と同じ意味を表す。

However, in the reaction formula (1), X has the same meaning as in the general formula (4).

ただし、前記反応式（２）中、Ｒ₄及びＸは、前記一般式（４）と同じ意味を表す。

However, in the reaction formula (2), R ₄ and X have the same meaning as in the general formula (4).

The compound represented by the general formula (5) is not particularly limited and may be appropriately selected depending on the purpose. For example, polyethylene glycol monomethacrylate or polyethylene glycol monomethacrylate in which n and m are in the above ranges. Examples thereof include acrylate, methoxy polyethylene glycol methacrylate, methoxy polyethylene glycol acrylate, polyethylene glycol polypropylene glycol monomethacrylate and the like. These may be used alone or in combination of two or more.
As the compound represented by the general formula (5), those synthesized appropriately may be used, or commercially available products may be used. Examples of the commercially available product include Bremmer PE-90, PE-200, PE-350, AE-90U, AE-200, AE-400, PME-100, PME-200, PME-400, PME-1000, PME. -4000, AME-200, AME-400, 50PEP-300, 70PEP-350B (all are NOF Corporation) etc. are mentioned.

As a method for synthesizing the copolymer, a method using a radical polymerization initiator is preferable, and a solution polymerization method in which a polymerization reaction is carried out in a solution is more preferable, because the polymerization operation and the adjustment of the molecular weight are easy.
As a preferable solvent when performing radical polymerization by the solution polymerization method, for example, a ketone solvent such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, an ethyl acetate, an acetic acid ester solvent such as butyl acetate, benzene, toluene, xylene, and the like. Examples thereof include aromatic hydrocarbon solvents, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, hexamethylphosphoamide and the like. These may be used alone or in combination of two or more. Among these, ketone solvents, acetic acid ester solvents, and alcohol solvents are preferable.

  The radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate and peroxy ester. , Cyano-based azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobis (2,2'-isovaleronitrile), non-cyano-based dimethyl-2,2'-azobisisobutyrate, etc. Is mentioned. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable, because the molecular weight is easily controlled and the decomposition temperature is low.

  The content of the radical polymerization initiator is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1% by mass or more and 10% by mass or less based on the total amount of the polymerizable monomers.

An appropriate amount of a chain transfer agent may be added to adjust the molecular weight of the polymer.
Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecylmercaptan, 1-dodecanethiol, and thioglycerol.
The polymerization temperature is appropriately selected depending on the intended purpose without any limitation, but it is preferably 50 ° C or higher and 150 ° C or lower, more preferably 60 ° C or higher and 100 ° C or lower. The polymerization time is appropriately selected depending on the intended purpose without any limitation, but it is preferably 3 hours or more and 48 hours or less.

The copolymer used in the present invention is not particularly limited, and can be used as a pigment dispersant or an additive to a pigment dispersion. When used as a pigment dispersant, further improvement in storage stability is recognized in inks containing a large amount of water-soluble organic solvent.
The content of the copolymer used in the present invention, when used as a pigment dispersant, is not particularly limited and can be appropriately selected according to the purpose, but with respect to 100 parts by mass of the pigment, The amount is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 80 parts by mass or less. When the content is within the more preferable range, it is advantageous in that the image density and the storage stability are good. Further, other dispersants may be used in combination as long as the effect of the copolymer as a dispersant is not impaired.

The content of the copolymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.05% by mass or more and 10% by mass or less in terms of solid content, based on the total amount of the ink, It is more preferably 0.3% by mass or more and 5% by mass or less.
When the content is 0.05% by mass or more, the effect of improving dispersibility and storability is recognized, and when the content is 10% by mass or less, the viscosity range suitable for ejecting the ink from the head can be obtained. Become.

<Water>
As the water, for example, deionized water, ultrafiltered water, reverse osmosis water, pure water such as distilled water, or highly pure water can be used.
The content of the water in the ink is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10% by mass or more and 90% by mass or less from the viewpoint of ink drying property and ejection reliability. 20 mass% or more and 60 mass% or less are more preferable.

<Color material>
As the color material, a pigment or a dye can be used. Pigments are preferable in terms of adsorption ability of the above-mentioned copolymer to a coloring material, because pigments are superior to dyes, and water resistance and light resistance.

  The pigment is appropriately selected depending on the intended purpose without any limitation, and examples thereof include black or color inorganic pigments and organic pigments. These may be used alone or in combination of two or more.

Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and a known method such as a contact method, a furnace method, and a thermal method. The carbon black prepared can be used.
Examples of black pigments include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). , Metal oxides such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
The carbon black is a carbon black produced by a furnace method or a channel method and has a primary particle size of 15 nm or more and 40 nm or less, a specific surface area by the BET method of 50 m ² / g or more and 300 m ² / g or less, and a DBP oil absorption of 40 mL. / 100 g or more and 150 mL / 100 g or less, those having a volatile content of 0.5% or more and 10% or less, and a pH of 2 or more and 9 or less are preferable.

Examples of the organic pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, Dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofuraron pigments, etc.), dye chelates (eg, basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used.
Of these pigments, those having a good affinity for water are particularly preferably used.

Examples of the azo pigment include azo lake, insoluble azo pigment, condensed azo pigment, chelate azo pigment, and the like.
Examples of the polycyclic pigments include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofuraron pigments, and rhodamine B lake pigments. .
Examples of the dye chelates include basic dye chelates and acid dye chelates.

  The yellow pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 16, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 73, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 75, C.I. I. Pigment Yellow 83, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 95, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 98, C.I. I. Pigment Yellow 114, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 129, C.I. I. Pigment Yellow 138, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 174, C.I. I. Pigment Yellow 180 and the like.

  The magenta pigment is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. Pigment Red 48 (Mn), C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 112, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 146, C.I. I. Pigment Red 168, C.I. I. Pigment Red 176, C.I. I. Pigment Red 184, C.I. I. Pigment Red 185, C.I. I. Pigment Red 202, Pigment Violet 19, and the like.

  The cyan pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15: 4, C.I. I. Pigment Blue 15:34, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 22, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 63, C.I. I. Pigment Blue 66; C.I. I. Bat Blue 4, C.I. I. Bat blue 60 and the like can be mentioned.

  As a yellow pigment, C.I. I. Pigment Yellow 74 and C.I. as a magenta pigment. I. Pigment Red 122, C.I. I. Pigment Bio Red 19 and C.I. as a cyan pigment. I. By using Pigment Blue 15: 3, a well-balanced ink having excellent color tone and light resistance can be obtained.

The coloring material newly manufactured for the present invention can also be used for the ink of the present invention.
Further, from the viewpoint of color developability of the obtained image, a self-dispersion pigment may be used, and an anionic self-dispersion pigment is preferable. The anionic self-dispersion pigment refers to a pigment that is dispersion-stabilized by introducing an anionic functional group into the pigment surface directly or through another atomic group.
As the pigment before dispersion stabilization, various conventionally known pigments such as those listed in WO 2009/014242 can be used.
The anionic functional group means a functional group capable of dissociating more than half of hydrogen ions at pH 7.0. Specific examples of the anionic functional group include a carboxyl group, a sulfo group, and a phosphonic acid group. Of these, a carboxyl group or a phosphonic acid group is preferable from the viewpoint of increasing the optical density of the obtained image.
Examples of the method of introducing an anionic functional group onto the surface of the pigment include a method of oxidizing carbon black.
Specific examples of the oxidation treatment method include a method of treating with hypochlorite, ozone water, hydrogen peroxide, chlorite, nitric acid, or the like, Japanese Patent No. 3808504, Japanese Patent Publication No. 2009-515007, And a surface treatment method using a diazonium salt as described in JP-A-2009-506196.
Examples of commercially available pigments having hydrophilic functional groups introduced on the surface include CW-1, CW-2, CW-3 (above, manufactured by Orient Chemical Industry Co., Ltd.); CAB-O-JET200, CAB- O-JET300, CAB-O-JET400 (above, Cabot Corporation make) etc. are mentioned.

  The content of the pigment in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5% by mass or more and 20% by mass or less, and 1% by mass or more and 10% by mass or less. More preferable.

As the dye, a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and an edible dye in the color index can be used.
Examples of the acid dye and the food dye include C.I. I. Acid Black 1, 2, 7, 24, 26, 94, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Blue 9, 29, 45, 92, 249, C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254, 289, C.I. I. Food Black 1, 2, C.I. I. Food Yellow 3, 4, C.I. I. Hood Red 7, 9, 14 and the like can be mentioned.
Examples of the direct dye include C.I. I. Direct Black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, (168), 171, C.I. I. Direct Yellow 1, 12, 24, 26, 33, 44, 50, 86, 120, 132, 142, 144, C.I. I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202, C.I. I. Direct Red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227, C.I. I. Direct Orange 26, 29, 62, 102 and the like can be mentioned.
Examples of the basic dye include C.I. I. Basic Black 2, 8, C.I. I. Basic Yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65, 67, 70, 73, 77, 87, 91, C.I. I. Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93, 105, 117, 120, 122, 124, 129, 137, 141, 147, 155, C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70, 73, 78, 82, 102, 104, 109, 112 and the like.
Examples of the reactive dye include C.I. I. Reactive Black 3, 4, 7, 11, 12, 17, C.I. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65, 67, C.I. I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, C.I. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97 and the like.

  The ink of the present invention is an organic solvent in order to enhance the permeability to plain paper, coated paper, etc., to further suppress the occurrence of beading, and to prevent the ink from drying by utilizing the wetting effect. It is preferable to contain

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3- Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol and petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol monoethyl ether Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -Pyrrolidone, 1,3-dimethyl-2-imidazolidinone, nitrogen-containing heterocyclic compounds such as ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples include ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or less because it not only functions as a wetting agent but also obtains good drying properties.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  The polyol compound having 8 or more carbon atoms and the glycol ether compound can improve the ink permeability when paper is used as the recording medium.

  The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the purpose, but from the viewpoint of ink drying properties and ejection reliability, 10% by mass or more and 60% by mass or less is preferable, 20 mass% or more and 60 mass% or less are more preferable.

  The ink of the present invention preferably contains a surfactant in order to enhance the penetrability and wettability of plain paper, coated paper and the like, and further suppress the occurrence of beading.

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-chain both-end modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound having a polyalkylene oxide structure introduced into the side chain of the Si moiety of dimethylsiloxane.
Examples of the fluorinated surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, a perfluoroalkyl ethylene oxide adduct and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salts. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in its side chain include a sulfuric acid ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in its side chain and a perfluoroalkyl ether group in its side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counterions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). ₃ etc.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan. Examples thereof include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, and salt of polyoxyethylene alkyl ether sulfate.
These may be used alone or in combination of two or more.

（但し、一般式（Ｓ−１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ−６１８、ＫＦ−６４２、ＫＦ−６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ−ＳＳ−５６０２、ＳＳ−１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ−２１０５、ＦＺ−２１１８、ＦＺ−２１５４、ＦＺ−２１６１、ＦＺ−２１６２、ＦＺ−２１６３、ＦＺ−２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ−３３、ＢＹＫ−３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-modified polydimethylsiloxane. Examples thereof include polydimethyl siloxane modified at both chain ends, and a polyether modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group shows good properties as an aqueous surfactant. preferable.
As such a surfactant, those synthesized appropriately may be used, or commercially available products may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Kagaku Co., Ltd., and the like.
The polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polyalkylene oxide structure represented by the general formula (S-1) may be dimethylpolyethylene. Examples thereof include those introduced into the side chain of the Si portion of siloxane.

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)
As the above polyether-modified silicone-based surfactant, commercially available products can be used, for example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-. 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

上記一般式（Ｆ−１）で表される化合物において、水溶性を付与するためにｍは０〜１０の整数が好ましく、ｎは０〜４０の整数が好ましい。
一般式（Ｆ−２）
Ｃ_nＦ_2n+1−ＣＨ₂ＣＨ(ＯＨ)ＣＨ₂−Ｏ−(ＣＨ₂ＣＨ₂Ｏ)_ａ−Ｙ
上記一般式（Ｆ−２）で表される化合物において、ＹはＨ、又はＣ_mＦ_2m+1でｍは１〜６の整数、又はＣＨ₂ＣＨ(ＯＨ)ＣＨ₂−Ｃ_mＦ_2m+1でｍは４〜６の整数、又はＣ_pＨ_2p+1でｐは１〜１９の整数である。ｎは１〜６の整数である。ａは４〜１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。この市販品としては、例えば、サーフロンＳ−１１１、Ｓ−１１２、Ｓ−１１３、Ｓ−１２１、Ｓ−１３１、Ｓ−１３２、Ｓ−１４１、Ｓ−１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ−９３、ＦＣ−９５、ＦＣ−９８、ＦＣ−１２９、ＦＣ−１３５、ＦＣ−１７０Ｃ、ＦＣ−４３０、ＦＣ−４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ−４７０、Ｆ−１４０５、Ｆ−４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ−１００、ＦＳＮ、ＦＳＯ−１００、ＦＳＯ、ＦＳ−３００、ＵＲ、キャプストーンＦＳ−３０、ＦＳ−３１、ＦＳ−３１００、ＦＳ−３４、ＦＳ−３５（いずれも、Ｃｈｅｍｏｕｒｓ社製）；ＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ−１３６Ａ，ＰＦ−１５６Ａ、ＰＦ−１５１Ｎ、ＰＦ−１５４、ＰＦ−１５９（オムノバ社製）、ユニダインＤＳＮ−４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｃｈｅｍｏｕｒｓ社製のＦＳ−３１００、ＦＳ−３４、ＦＳ−３００、株式会社ネオス製のＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ、オムノバ社製のポリフォックスＰＦ−１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ−４０３Ｎが特に好ましい。 The fluorine-based surfactant is preferably a fluorine-substituted compound having 2 to 16 carbon atoms, and more preferably a fluorine-substituted compound having 4 to 16 carbon atoms.
Examples of the fluorinated surfactant include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has a low foaming property, and is particularly preferably a fluorine-based compound represented by the general formula (F-1) or the general formula (F-2). Surfactants are preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
General formula (F-2)
_{C n F 2n + 1 -CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the above general formula (F-2), Y is H, or C _m F _{2m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ -C _m F _{2m +. In 1} , m is an integer of 4 to 6, or C _p H _{2p + 1} and p is an integer of 1 to 19. n is an integer of 1-6. a is an integer of 4-14.
A commercially available product may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250. FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (Omnova Corporation) , Manufactured by Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) and the like. Among these, good printing quality, especially color development, penetrability into paper, wettability, and leveling property are remarkably improved. Chemours FS-3100, FS-34, FS-300, Neos FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW, OMNOVA Poly. Fox PF-151N and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

  The content of the surfactant in the ink is appropriately selected depending on the intended purpose without any limitation, but it is 0.001 mass% from the viewpoint of excellent wettability and ejection stability and improving image quality. % Or more and 5 mass% or less is preferable, and 0.05 mass% or more and 5 mass% or less is more preferable.

  The ink of the present invention preferably contains, as necessary, other components such as an antiseptic / antifungal agent, a rust inhibitor, and a pH adjusting agent.

<Antiseptic and fungicide>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
The rust preventive agent is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and may be appropriately selected depending on the purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, from the viewpoint that the printing density and character quality are improved, and that good ejection properties can be obtained, and 5 mPa · s or more and 25 mPa · s or less are preferable. More preferable. Here, as the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. The measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less at 25 ° C., and more preferably 32 mN / m or less at 25 ° C., since the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing the corrosion of the metal member with which the ink comes into contact.

  The ink of the present invention can be used as an inkjet ink, and can be used in an inkjet recording device and an inkjet recording method.

<Ink manufacturing method>
The method for producing an ink of the present invention is a method for producing an ink containing water, a coloring material, and a copolymer,
It includes a step of synthesizing a copolymer, and further includes other steps as necessary.
The step of synthesizing the copolymer is the same as the method of synthesizing the copolymer.

Examples of the other steps include a mixing step and the like.
The mixing step is a step of dispersing or dissolving the water, the coloring material, the copolymer, and the other components, and stirring and mixing.
The copolymer may be used as a pigment-dispersing resin when producing a pigment dispersion.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, ultrasonic dispersion, or the like. The stirring and mixing can be performed with a stirrer using a normal stirring blade, a magnetic stirrer, a high speed disperser, or the like.

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

<Recorded matter>
The ink recorded matter of the invention has an image formed by using the ink of the invention on a recording medium.
A recorded matter can be obtained by recording with an inkjet recording apparatus and an inkjet recording method.

ただし、前記一般式（１）中、Ｒ₁は水素原子又はメチル基を表し、Ｘは炭素数２〜１０のアルキレン基を表す。

ただし、前記一般式（２）中、Ｒ₂及びＲ₃は、水素原子又はメチル基を表し、ｎは１〜９０、ｍは０〜９０の整数を表す。
本発明のインクを用い、インクジェット記録装置及びインクジェット記録方法により記録して記録物とすることができる。 That is, the recorded matter of the present invention is a recorded matter having a recording layer on a recording medium, and the recording layer contains a coloring material and a copolymer, and further contains other components as necessary.
The copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.
The ink of the present invention can be used as a recorded matter by recording with an inkjet recording apparatus and an inkjet recording method.

<Ink container>
The ink storage container of the present invention is an ink storage container including an ink storage portion that stores ink, and the ink stored in the ink storage portion is the ink of the present invention. The ink is contained in a container, and further has other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose, and examples thereof include an ink laminated portion formed of an aluminum laminate film, a resin film, or the like. At least those having, for example, a main tank having an ink containing portion, an ink cartridge, and the like are suitable.

<Recording device, recording method>
The ink of the present invention can be suitably used for various recording apparatuses using an inkjet recording method, such as printers, facsimile machines, copying machines, printer / fax / copier composite machines, and three-dimensional modeling apparatuses.
In the present invention, the recording device and the recording method are a device capable of ejecting ink, various treatment liquids, and the like onto a recording medium, and a method of recording using the device. The recording medium means a medium to which ink or various treatment liquids can be attached even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means for feeding, conveying, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. .
The recording device and the recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, but, for example, a warm air heater or an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording device and the recording method are not limited to those in which a significant image such as a character or a figure is visualized by ink. For example, the thing which forms patterns, such as a geometric pattern, and the thing which models a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head unless otherwise limited.
Further, this recording device is not limited to a desktop type, and can be used as a wide recording device capable of printing on an A0 size recording medium, or for example, a continuous paper wound in a roll as a recording medium. It also includes a continuous form printer.
An example of the recording device will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packed with, for example, an aluminum laminate film. It is formed of a member. The ink container 411 is housed in a container case 414 made of plastics, for example. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus body is opened. The main tank 410 is detachably attached to the cartridge holder 404. As a result, the ink discharge ports 413 of the main tank 410 communicate with the ejection heads 434 for the respective colors via the supply tubes 436 for the respective colors, and ink can be ejected from the ejection heads 434 to the recording medium.

  The method of using the ink is not limited to the ink jet recording method and can be widely used. In addition to the inkjet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected according to the purpose. For example, the ink can be applied to printed matter, paints, coating materials, bases and the like. Further, it can be used not only as a two-dimensional character or image by using as ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional model).
As a three-dimensional modeling device for modeling a three-dimensional molded object, a known one can be used and is not particularly limited, but for example, one provided with an ink containing means, a supplying means, a discharging means, a drying means, etc. is used. be able to. The three-dimensional molded item includes a three-dimensional molded item obtained by overcoating with ink. Further, it also includes a molded product obtained by processing a structure to which ink is applied on a substrate such as a recording medium. The molded product is, for example, a molded product such as a sheet-shaped or film-shaped recorded product or a structure, which is subjected to a molding process such as heat drawing or punching process. -Suitable for applications such as electronic devices, meters for cameras, panels for operation parts, etc., after molding the surface after molding.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.
Further, the average molecular weight of the copolymers used in Examples and Comparative Examples was determined as follows.

<Measurement of average molecular weight of copolymer>
It measured on GPC (Gel Permeation Chromatography) on the following conditions.
-Device: GPC-8020 (manufactured by Tosoh Corporation)
・ Column: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
-Flow rate: 1.0 mL / min. 1 mL of a copolymer having a concentration of 0.5% by mass was injected, and a molecular weight calibration curve prepared by a monodisperse polystyrene standard sample was used from the molecular weight distribution of the copolymer measured under the above conditions. Then, the number average molecular weight Mn and the weight average molecular weight Mw of the copolymer were calculated.

次に、３５．７ｇ（１５５ｍｍｏｌ）の構造式（Ａ−１）で表される反応中間体を１００ｍＬの乾燥メチルエチルケトンに溶解し、５０℃まで加熱した。この溶液に、２４．０ｇ（１５５ｍｍｏｌ）の２−メタクリロイルオキシエチルイソシアネート（昭和電工社製、カレンズＭＯＩ）を２０ｍＬの乾燥メチルエチルケトンに溶解した溶液を、１時間かけて攪拌しながら滴下した後、６０℃で１２時間攪拌した。室温まで冷却した後、溶媒を留去した。残留物を、溶離液としてｎ−ヘキサン／酢酸エチル（体積比２／１）混合溶媒を用いて、シリカゲルカラムクロマトグラフィーにより精製し、４４．２ｇのモノマーＭ−１を得た。

(Monomer synthesis example 1)
-Synthesis of Monomer M-1-
150.0 g (2.41 mol) of ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) and 50.0 g (0.268 mol) of 1-naphthalene acetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a reaction vessel and stirred to 70 It was heated to ℃ and dissolved. 1.10 g of concentrated sulfuric acid was added, and the mixture was stirred at 70 ° C. for 3 hours. After cooling to room temperature, 250 ml of a solution prepared by dissolving 1.80 g of sodium hydroxide in 500 ml of water was added. After 200 ml of ethyl acetate was added and the mixture was washed with water, the organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using hexane / ethyl acetate (volume ratio 3/2) mixed solvent as an eluent, and 38.7 g of a reaction intermediate represented by the following structural formula (A-1). Got the body

Next, 35.7 g (155 mmol) of the reaction intermediate represented by Structural Formula (A-1) was dissolved in 100 mL of dry methyl ethyl ketone, and heated to 50 ° C. To this solution, a solution of 24.0 g (155 mmol) of 2-methacryloyloxyethyl isocyanate (Karenzu MOI manufactured by Showa Denko KK) dissolved in 20 mL of dry methyl ethyl ketone was added dropwise with stirring over 1 hour, and then at 60 ° C. It was stirred for 12 hours. After cooling to room temperature, the solvent was distilled off. The residue was purified by silica gel column chromatography using n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent to obtain 44.2 g of monomer M-1.

(Monomer synthesis examples 2 to 4)
-Synthesis of Monomers M-2 to 4-
In order to synthesize M-2 to 4 instead of ethylene glycol or 2-methacryloyloxyethyl isocyanate in the synthesis of the monomer M-1, the following diols or isocyanates were used in the same manner except that [Monomers M-2 to 4] were obtained.
For M-2: 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 2-methacryloyloxyethyl isocyanate For M-3: 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 2-acryloyloxyethyl isocyanate (Showa Denko KK, Karens AOI)
For M-4: 1,10-decanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 2-methacryloyloxyethyl isocyanate

(Synthesis Example 1 of Copolymer)
-Synthesis of Copolymer CP-1-
52.3 g (47.0 mmol) of methoxy polyethylene glycol methacrylate (Blenmer PEM-1000, manufactured by NOF CORPORATION) and 47.7 g (123.8 mmol) of monomer M-1 were dissolved in 200 mL of dry methyl ethyl ketone. A solution was prepared. After heating 10% by mass of the monomer solution to 75 ° C. under an argon stream, 4.00 g of 2,2′-azobis (isobutyronitrile) (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the remaining monomer solution. The dissolved solution was added dropwise over 1.5 hours, and the mixture was stirred at 75 ° C for 6 hours. After cooling to room temperature, the obtained reaction solution was dropped into hexane. The precipitated copolymer was separated by filtration and dried under reduced pressure to obtain 98.2 g of [copolymer CP-1] (weight average molecular weight (Mw): 21,300).

(Synthesis examples 2 to 12 of copolymer)
-Synthesis of Copolymers CP-2 to 12-
In Synthesis Example 1 of the copolymer, the monomers represented by the general formula (4) and the general formula (5) in the contents (parts by mass) shown in Table 1 and other monomers are used, and Table 1 In the same manner as in Synthesis Example 1 of the copolymer, except that the content (parts by mass) of the polymerization initiator (AIBN) and the chain transfer modifier (thioglycerol) shown in the above were used, [copolymer CP-2 to 12] was obtained.
The weight average molecular weight Mw of each of the obtained copolymers CP-2 to 12 is as shown in Table 1.

表１中、ドデシルメタクリレート、スチレンは東京化成工業社製のものを用いた。

In Table 1, dodecyl methacrylate and styrene used were those manufactured by Tokyo Chemical Industry Co., Ltd.

(Preparation Example 1 of pigment dispersion)
-Preparation of Pigment Dispersion PD-1-
To 40.0 parts by mass of a 10% by mass aqueous solution of the copolymer CP-1, 16.0 parts by mass of carbon black (NIPEX150, manufactured by Degussa) and 44.0 parts by mass of ion-exchanged water were added and stirred for 12 hours. did. The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk type bead mill (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., media: zirconia balls having a diameter of 0.1 mm) was used, and then the average pore diameter was obtained. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [pigment dispersion PD-1] (pigment solid content concentration: 16% by mass).

(Preparation Examples 2 to 17 of pigment dispersion)
-Preparation of Pigment Dispersions PD-2 to 17-
In Preparation Example 1 of Pigment Dispersion, except that the copolymers CP-2 to 12 were used in the contents (parts by mass) shown in Table 2 and the pigments shown in Table 2 were used, In the same manner, pigment dispersions PD-2 to 17 were obtained.

なお、表２中、カーボンブラック以外の顔料は下記の製品を使用した。
・ピグメントブルー１５：３
（クロモファインブルーＡ−２２０ＪＣ、大日精化株式会社製）
・ピグメントレッド１２２（トナーマゼンタＥＯ０２、クラリアント社製）
・ピグメントイエロー７４（ファーストイエロー５３１、大日精化工業株式会社製）

In Table 2, the following products were used as pigments other than carbon black.
・ Pigment Blue 15: 3
(Chromofine Blue A-220JC, manufactured by Dainichiseika Co., Ltd.)
Pigment Red 122 (Toner Magenta EO02, Clariant)
・ Pigment Yellow 74 (First Yellow 531, manufactured by Dainichiseika Kogyo Co., Ltd.)

(Example 1)
-Preparation of Ink GJ-1-
40.0 parts by mass of pigment dispersion PD-1, 10.0 parts by mass of glycerin, 20.0 parts by mass of 1,3-butanediol, 10.0 parts by mass of 3-methoxy-N, N-dimethylpropione Amide, 1.0 part by mass of 2-ethyl-1,3-hexanediol, 1.0 part by mass of 2,2,4-trimethyl-1,3-pentanediol, 1.0 part by mass of Unidyne DSN-403N (Manufactured by Daikin Industries, Ltd.) and 17.0 parts by mass of ion-exchanged water are mixed and stirred for 1 hour, and then filtered through a membrane filter having an average pore size of 1.2 μm to obtain the ink GJ-1 of Example 1. It was made.

(Examples 2 to 17)
-Preparation of Inks GJ-2 to 17-
Inks GJ-2 to 17 of Examples 2 to 17 were prepared in the same manner as in Example 1 except that the ink formulation shown in Table 3 was changed.
In Table 3, the numerical values in the columns of water-soluble organic solvent, surfactant and ion-exchanged water indicate parts by mass.

(Comparative Example 1)
-Preparation of Ink RGJ-1-
A monomer solution was prepared by dissolving 8.20 g of methoxypolyethylene glycol methacrylate (n≈23) and 7.03 g of a monomer having a structure represented by the following structural formula (6) in 30 mL of dry methyl ethyl ketone. After heating 10% by mass of the monomer solution to 75 ° C. under an argon stream, a solution in which 0.556 g of 2,2-azobis (isobutyronitrile) was dissolved in the remaining monomer solution was taken for 1.5 hours. The mixture was added dropwise and stirred at 75 ° C for 6 hours. After cooling to room temperature, the obtained reaction solution was added to hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 14.11 g of a copolymer (weight average molecular weight (Mw): 12,500). The obtained copolymer was used as a comparative copolymer RCP-1.

Then, using this, in the same manner as in Example 1, a 10 mass% aqueous solution of the comparative copolymer RCP-1 was prepared.
Next, as Example 1 except that a 10 mass% aqueous solution of the copolymer CP-1 was used in place of the 10 mass% aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 1. Similarly, a comparative pigment dispersion RPD-1 was obtained.
Next, a comparative ink RGJ-1 was obtained in the same manner as in Example 1 except that the comparative pigment dispersion RPD-1 was used instead of the pigment dispersion PD-1 in the production of the ink of Example 1. .

(Comparative example 2)
-Preparation of Ink RGJ-2-
In the same manner as in Example 15 except that the 10% by mass aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 15 was used instead of the 10% by mass aqueous solution of the comparative copolymer RCP-1. , Comparative pigment dispersion RPD-2 was obtained.
Next, Comparative Ink RGJ-2 was obtained in the same manner as in Example 15 except that Comparative Pigment Dispersion RPD-2 was used instead of Pigment Dispersion PD-15 in the production of the ink of Example 15. .

(Comparative example 3)
-Preparation of Ink RGJ-3-
In the same manner as in Example 16 except that the 10% by mass aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 16 was used instead of the 10% by mass aqueous solution of the comparative copolymer RCP-1. , Comparative pigment dispersion RPD-3 was obtained.
Next, Comparative Ink RGJ-3 was obtained in the same manner as in Example 16 except that Comparative Pigment Dispersion RPD-3 was used instead of Pigment Dispersion PD-16 in the production of the ink of Example 16. .

(Comparative example 4)
-Preparation of Ink RGJ-4-
In the same manner as in Example 17, except that the 10 mass% aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 17 was used instead of the 10 mass% aqueous solution of the comparative copolymer RCP-1. , Comparative pigment dispersion RPD-4 was obtained.
Next, Comparative Ink RGJ-4 was obtained in the same manner as in Example 17, except that Comparative Pigment Dispersion RPD-4 was used instead of Pigment Dispersion PD-17 in the ink preparation of Example 17.

(Comparative example 5)
-Preparation of Ink RGJ-5-
80 g of 2-phenoxyethyl methacrylate as a monomer, 3.7 g of 3-mercapto-1-propanol as a chain transfer agent, and 0.3 g of 2,2-azobis (2,4-dimethylvaleronitrile) as an initiator as tetrahydrofuran ( THF) (160 mL), and heated to 65 ° C. in a nitrogen atmosphere and reacted for 7 hours. The resulting solution was allowed to cool, 80 mg of dibutyltin dilaurate (IV) and a catalytic amount of hydroquinone were added, and 10.0 g of 2-methacryloyloxyethyl isocyanate was added dropwise. After heating to 50 ° C. and reacting for 2.5 hours, reprecipitation was performed with a mixed solvent of methanol and water for purification, and 71 g of macromonomer MM-1 (weight average molecular weight (Mw): 4,000, The number average molecular weight (Mn): 1,900) was obtained.
Next, after heating 20 g of methyl ethyl ketone to 75 ° C. under a nitrogen atmosphere, 1.16 g of dimethyl 2,2′-azobisisobutyrate, 9 g of the macromonomer MM-1 obtained above, 1.8 g A solution of p-styrene sulfonic acid (4) and 49.2 g of methyl methacrylate dissolved in 40 g of methyl ethyl ketone was added dropwise over 3 hours. After completion of the dropping, the reaction was continued for 1 hour, then a solution of 0.2 g of dimethyl 2,2'-azobisisobutyrate dissolved in 0.6 g of methyl ethyl ketone was added, the temperature was raised to 80 ° C, and the mixture was heated and stirred for 4 hours. did. Further, a solution prepared by dissolving 0.2 g of dimethyl 2,2′-azobisisobutyrate in 0.6 g of methyl ethyl ketone was added, and the mixture was heated and stirred for 6 hours. After cooling, the obtained reaction solution was dropped into hexane, and the precipitated graft polymer was separated by filtration and dried to obtain a comparative copolymer RCP-2 (weight average molecular weight (Mw): 22,000). .

-Preparation of Pigment Dispersion RPD-5-
Then, the same as Example 1 except that a 10 mass% aqueous solution of the comparative copolymer RCP-2 was used instead of the 10 mass% aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 1. To obtain Comparative Pigment Dispersion RPD-5.
Next, Comparative Ink RGJ-5 was obtained in the same manner as in Example 1 except that Comparative Pigment Dispersion RPD-5 was used in place of Pigment Dispersion PD-1 in the production of the ink of Example 1. .

(Comparative example 6)
<Preparation of Ink RGJ-6>
-Synthesis of Copolymer RCP-3-
72.0 g (500 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.), 125.0 g (1,000 mmol) of ethylene glycol mono-2-chloroethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), 500 mL of N -Methyl-2-pyrrolidinone (manufactured by Kanto Chemical Co., Inc.) was dissolved and stirred at room temperature for 1 hour. Furthermore, it stirred at 110 degreeC for 10 hours. After cooling to room temperature, 2,500 mL of pure water was added to the obtained reaction solution, and the mixture was stirred at room temperature for 1 hour. The precipitated solid was filtered off and dried under reduced pressure.
70.0 g of the solid obtained by the above reaction, 45.0 g (450 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 250 mL of tetrahydrofuran, and the mixture was stirred in an ice bath for 30 minutes. 36.6 g (350 mmol) of methacryloyl chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was slowly added dropwise thereto, and the mixture was further stirred in an ice bath for 3 hours. To the obtained solution, 250 mL of ethyl acetate and 100 mL of pure water were added and washed with water. Next, the ethyl acetate layer was isolated and washed with a saturated saline solution. The ethyl acetate layer was isolated, dried over magnesium sulfate, and the solvent was evaporated. The residue was purified by silica gel column chromatography to obtain 80.5 g of the monomer of the following structural formula (7).

  Next, 12.0 g of methyl ethyl ketone was added to a 100 mL three-necked flask equipped with a stirrer and a cooling tube, and heated to 72 ° C. under an argon stream. Here, 2.4 g (8.00 mmol) of the monomer of the structural formula (7), 1.2 g (13.9 mol) of methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and 7.8 g (44.3 mmol) of methacryl. Benzyl acid salt (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.6 g (0.54 mmol) of Bremmer PME-1000 (manufactured by NOF CORPORATION), 0.14 g (0.61 mmol) of 2,2′-azobis (isobutyric acid) ) A solution prepared by dissolving dimethyl (manufactured by Wako Pure Chemical Industries, Ltd.) in 6.0 g of methyl ethyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was further reacted for 1 hour, and a solution prepared by dissolving 0.06 g (0.26 mmol) of dimethyl 2,2′-azobis (isobutyrate) in 2.0 g of methyl ethyl ketone was added and heated to 78 ° C. Stir for hours. After that, reprecipitation was repeated twice with hexane to purify the copolymer. After the purification treatment, the copolymer was filtered off and dried under reduced pressure to obtain 11.5 g of comparative copolymer RCP-3 (weight average molecular weight (Mw): 31,800).

-Preparation of Pigment Dispersion RPD-6-
4.0 parts by mass of the copolymer RCP-3 was added to 1.9 parts by mass of a 35% by mass tetraethylammonium hydroxide aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd.) and 50.0 parts by mass of 3-methoxy-N, N. It was dissolved in'-dimethylpropionamide and 28.1 parts by mass of ion-exchanged water.
To an aqueous solution of 84.0 parts by mass of the copolymer RCP-3, 16.0 parts by mass of carbon black (NIPEX150, manufactured by Degussa) was added and stirred for 12 hours. The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk type bead mill (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., media: zirconia balls having a diameter of 0.1 mm) was used, and then the average pore diameter was obtained. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 95.0 parts by mass of comparative pigment dispersion RPD-6 (pigment solid content concentration: 16% by mass).

-Preparation of Ink RGJ-6-
40.0 parts by weight of comparative pigment dispersion RPD-6, 10.0 parts by weight of 1,3-butanediol, 10.0 parts by weight of glycerin, 1.0 part by weight of 2-ethyl-1,3-hexane. Diol, 1.0 part by mass of 2,2,4-trimethyl-1,3-pentanediol, 1.0 part by mass of Unidyne DSN-403N (manufactured by Daikin Industries, Ltd., solid content 100% by mass), and 37. After mixing 0 part by mass of ion-exchanged water and stirring for 1 hour, the mixture was filtered through a membrane filter having an average pore size of 1.2 μm to obtain a water-based ink RGJ-6 of Comparative Example 6.

(Comparative Example 7)
<Preparation of Ink RGJ-7>
-Synthesis of Copolymer RCP-4-
32.5 g (525 mmol) of ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 700 mL of methylene chloride, and 20.7 g (262 mmol) of pyridine was added. A solution prepared by dissolving 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) in 100 mL of methylene chloride was added dropwise to this solution while stirring over 2 hours, and then stirred at room temperature for 6 hours. did. After the obtained reaction solution was washed with water, the organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 97/3) as an eluent to obtain 39.6 g of a reaction intermediate of the following structural formula (8).

Next, 32.4 g (150 mmol) of the reaction intermediate of structural formula (8) was dissolved in 250 mL of methylene chloride, and 20.0 g (198 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. This solution was cooled in an ice bath, and 20.0 g (191 mmol) of methacrylic acid chloride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added dropwise over 30 minutes, followed by stirring in the ice bath for 1 hour and at room temperature for 3 hours. . The precipitate was filtered off, the filtrate was washed with water, saturated aqueous sodium hydrogen carbonate solution and saturated brine, the organic phase was isolated, dried over magnesium sulfate, and the solvent was evaporated. The residue was purified by silica gel column chromatography using n-hexane / ethyl acetate (volume ratio 5/1) mixed solvent as an eluent to obtain 31.1 g of a monomer of the following structural formula (9).

  A monomer solution was prepared by dissolving 55.6 g (196 mmol) of the monomer of structural formula (9) and 44.4 g (39.9 mmol) of Bremmer PME-1000 (manufactured by NOF CORPORATION) in 200 mL of dry methyl ethyl ketone. . After heating 10% by mass of the monomer solution to 75 ° C. under an argon stream, 4.00 g of 2,2′-azobis (isobutyronitrile) (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the remaining monomer solution. The dissolved solution was added dropwise over 1.5 hours, and the mixture was stirred at 75 ° C for 6 hours. After cooling to room temperature, the obtained reaction solution was dropped into hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 97.2 g of copolymer RCP-4 (weight average molecular weight (Mw): 18,200).

Then, using this, in the same manner as in Example 1, a 10% by mass aqueous solution of the comparative copolymer RCP-4 was prepared.
Next, as Example 1 except that a 10 mass% aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of the Example 1 was used instead of the 10 mass% aqueous solution of the copolymer CP-1. Similarly, a comparative pigment dispersion RPD-7 was obtained.
Next, Comparative Ink RGJ-7 was obtained in the same manner as in Example 1 except that Comparative Pigment Dispersion RPD-7 was used in place of Pigment Dispersion PD-1 in the preparation of the ink of Example 1. .

  Next, various characteristics of the produced pigment dispersions of Examples 1 to 17 and Comparative Examples 1 to 7 and inks were evaluated as follows. The results are shown in Table 4.

前記粘度の測定には、粘度計（ＲＥ８０Ｌ、東機産業株式会社製）を使用し、２５℃における粘度を、５０回転で測定した。
〔評価基準〕
Ａ：粘度の変化率が±３％を超え、±５％以内
Ｂ：粘度の変化率が±５％を超え、±８％以内
Ｃ：粘度の変化率が±８％を超え、±１０％以内
Ｄ：粘度の変化率が±１０％を超え、±３０％以内
Ｅ：粘度の変化率が±３０％を超える（ゲル化して評価不能） <Storage stability of pigment dispersion>
Each pigment dispersion was filled in a glass container having a volume of 30 mL in an amount of 15 mL and stored at 70 ° C. for 2 weeks. The change rate of the viscosity after storage with respect to the viscosity before storage was obtained from the following formula, and evaluated according to the following criteria. In addition, C or more is practical.

A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity, and the viscosity at 25 ° C. was measured at 50 rotations.
〔Evaluation criteria〕
A: Change rate of viscosity exceeds ± 3%, within ± 5% B: Change rate of viscosity exceeds ± 5%, within ± 8% C: Change rate of viscosity exceeds ± 8%, ± 10% Within: D: The rate of change of viscosity exceeds ± 10%, within ± 30% E: The rate of change of viscosity exceeds ± 30% (evaluation is impossible due to gelation)

前記粘度の測定には、粘度計（ＲＥ８０Ｌ、東機産業株式会社製）を使用し、２５℃における粘度を、５０回転で測定した。
〔評価基準〕
Ａ：粘度の変化率が±３％を超え、±５％以内
Ｂ：粘度の変化率が±５％を超え、±８％以内
Ｃ：粘度の変化率が±８％を超え、±１０％以内
Ｄ：粘度の変化率が±１０％を超え、±３０％以内
Ｅ：粘度の変化率が±３０％を超える（ゲル化して評価不能） <Ink storage stability>
Each ink was filled in an ink container and stored at 70 ° C. for 1 week. The rate of change in viscosity after storage with respect to the viscosity before storage was obtained from the following formula and evaluated according to the following criteria. In addition, C or more is practical.

A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity, and the viscosity at 25 ° C. was measured at 50 rotations.
〔Evaluation criteria〕
A: Change rate of viscosity exceeds ± 3%, within ± 5% B: Change rate of viscosity exceeds ± 5%, within ± 8% C: Change rate of viscosity exceeds ± 8%, ± 10% Within: D: The rate of change of viscosity exceeds ± 10%, within ± 30% E: The rate of change of viscosity exceeds ± 30% (evaluation is impossible due to gelation)

<Image density>
Inkjet printer (IPSiO GX5000, manufactured by Ricoh Co., Ltd.) was filled with each ink under an environment of 23 ° C. and 50% RH, and 64 points of JIS X 0208 (1997), 2223 general made by Microsoft Word 2000 (manufactured by Microsoft) were used. A chart with symbols is stamped on plain paper 1 (XEROX4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and the symbol portion on the printed surface is marked with X-Rite 938 (X-Rite Co., Ltd.). (Manufactured) and color was evaluated according to the following criteria. In addition, C or more is practical.
As the print mode, a mode in which the "plain paper-standard fast" mode was changed to "no color correction" from the user setting for plain paper using a driver attached to the printer was used.
The general symbols of JIS X 0208 (1997) and 2223 are symbols whose outer shape is a square and whose entire surface is filled with ink.
〔Evaluation criteria〕
A: 1.25 or more and less than 1.27 B: 1.20 or more and less than 1.25 C: 1.10 or more and less than 1.20 D: less than 1.10 E: Pigment cannot be dispersed in the ink due to gelation. Cannot print

From the results in Table 4, the inks of Examples 1 to 17 containing the copolymer containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2), A high image density is obtained even when recorded on plain paper, and the storage stability is high. However, the inks of Comparative Examples 1 to 7 using the conventional graft polymer have a low image density and a long-term storage stability is poor. Turns out to be enough.
That is, using a copolymer containing a structural unit having a naphthyl group at the terminal of the side chain represented by the general formula (1) of Examples 1 to 17 and a structural unit represented by the general formula (2) The prepared pigment dispersions had excellent storage stability and image density as compared with the pigment dispersions prepared using the copolymers having no naphthyl group at the end of the side chain of Comparative Examples 1 to 5. It is considered that this is because the naphthyl group of the copolymer and the π-π interaction between the pigment increased the adsorptivity to the pigment.
In addition, as in Comparative Example 6, when a structural unit different from the structural unit represented by the general formula (1) is contained even if it has a naphthyl group at the end of the side chain, the ink preservability and image density are improved. It turned out to be low and difficult to obtain practical quality.
In addition, as in Comparative Example 7, when it has a structural unit having a naphthyl group at the end of the side chain and also has a structural unit represented by the general formula (2), the naphthyl group is at the end of the side chain. Different from the structural unit represented by the general formula (1), when the naphthyl group is present at a position close to the polymer main chain, the storage stability of the ink and the image density were insufficient. This is presumed to be because if a naphthyl group is present at a position close to the polymer main chain, the copolymerized hydrophilic group is forced to be present near the naphthyl group, and pigment adsorption of the naphthyl group is inhibited. It

400 image forming apparatus 401 exterior of image forming apparatus 401c cover of apparatus body 404 cartridge holder 410 main tanks 410k, 410c, 410m, 410y for each color of black (K), cyan (C), magenta (M), and yellow (Y) Main tank 411 Ink storage unit 413 Ink discharge port 414 Storage container case 420 Mechanism unit 434 Discharge head 436 Supply tube

JP, 2011-105866, A

Claims (12)

An ink containing water, a coloring material, and a copolymer,
An ink characterized in that the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90. The ink according to claim 1, wherein the structural unit represented by the general formula (2) is a structural unit represented by the following general formula (3).

However, in the general formula (3), R ₂ and R ₃ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 90.   The ink according to claim 1, wherein the content of the structural unit represented by the general formula (1) in the copolymer is 40% by mass or more and 70% by mass or less.   The ink according to claim 1, wherein the copolymer has a weight average molecular weight of 15,000 to 40,000.   The ink according to claim 1, wherein the coloring material is a pigment.   The ink according to claim 1, further containing at least one of an organic solvent and a surfactant.   The ink according to claim 1, wherein the ink is an inkjet ink. A method for producing an ink containing water, a coloring material, and a copolymer,
A method for producing an ink, comprising the step of synthesizing the copolymer by radical polymerization from a polymerizable material containing a monomer represented by the following general formula (4) and a monomer represented by the following general formula (5).

However, in the general formula (4), R ₄ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

In the general formula (5), R ₅ and R ₆ represent a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.   An ink containing container having an ink containing part for containing ink, wherein the ink contained in the ink containing part is the ink according to any one of claims 1 to 7.   An ink jet recording method comprising an ink ejection step of applying a stimulus to the ink according to any one of claims 1 to 7 to eject the ink to record an image.   An ink jet recording apparatus having an ink ejecting unit that applies a stimulus to the ink according to claim 1 to eject the ink to record an image. A recorded matter having a recording layer on a recording medium,
The recording layer contains a coloring material and a copolymer,
A recorded material, wherein the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).

However, in the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and X represents an alkylene group having 2 to 10 carbon atoms.

However, In the general formula (2), R ₂ and R ₃ represents a hydrogen atom or a methyl group, n represents. 1 to 90, m is an integer of 0-90.

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