JP7006488B2 - Ink, ink container, recording device, recording method, and recorded material - Google Patents

Description

The present invention relates to ink, an ink container, a recording device, a recording method, and a recorded material.

As the ink used in the inkjet recording method, a water-based ink using a dye or a pigment is known. With such inks, it is necessary to stably disperse components such as pigments, which are difficult to dissolve in water, in water for a long period of time, so it is effective to use a dispersant in combination.

Patent Document 1 discloses a dispersant which is a copolymer having a structural unit having an anionic group and a structural unit having a naphthyl group at the terminal, and ejects ink containing these dispersants to a recording medium by an inkjet method. It is disclosed that it can be done. Further, it is disclosed that the ink using these dispersants is excellent in storage stability, image density, and beading resistance.

However, the ejection of the inkjet head is stabilized by supplying the ink to the inkjet head that has been left for a long time in a state where the protective cap that suppresses the drying of the ink on the nozzle surface of the inkjet head is not attached to the inkjet head (decap state). In the case of restoring the property, the ink produced by using the conventional copolymer has a problem that the ejection recovery property is inferior.

（前記一般式（１）で表される構造単位において、Ｒ_２は水素原子又はメチル基であり、Ｌ_１は炭素数が２以上１８以下のアルキレン基である。）

（前記一般式（２）で表される構造単位において、Ｒ_３は水素原子又はメチル基であり、Ｌ_２は炭素数が２以上１２以下のアルキレン基、又はエーテル基を含み炭素数が４以上１２以下のアルキレン基である。）

（前記一般式（３）で表される構造単位において、Ｒ_４は水素原子又はメチル基である。） The invention according to claim 1 has a structural unit represented by the following general formula (1), further represented by a structural unit represented by the following general formula (2), and represented by the following general formula (3). An ink containing a copolymer substantially having at least one selected from structural units.

(In the structural unit represented by the general formula (1), R ₂ is a hydrogen atom or a methyl group, and L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms.)

(In the structural unit represented by the general formula (2), R ₃ is a hydrogen atom or a methyl group, and L ₂ contains an alkylene group having 2 or more and 12 or less carbon atoms or an ether group and has 4 or more carbon atoms. It is an alkylene group of 12 or less.)

(In the structural unit represented by the general formula (3), _R4 is a hydrogen atom or a methyl group.)

The ink of the present invention exerts an excellent effect of ejection recovery when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head that has been left in the decapped state for a long time.

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

Hereinafter, embodiments of the present invention will be described.

<< Ink >>
The ink of the present embodiment contains a copolymer and, if necessary, a component such as water, a coloring material, an organic solvent, and a surfactant.

<Copolymer>
The copolymer has a structural unit represented by the general formula (1), and is further selected from at least a structural unit represented by the general formula (2) and a structural unit represented by the general formula (3). Has substantially one. The copolymer may contain other structural units such as structural units having an anionic group, if necessary, in addition to the structural units represented by the general formulas (1) to (3).
The "structural unit" in the present embodiment indicates the minimum repeating unit of the polymer obtained by bonding the polymerizable monomers (monomers) to each other.

一般式（１）で表される構造単位において、Ｒ_２は水素原子又はメチル基である。また、Ｌ_１は炭素数が２以上１８以下のアルキレン基であり、炭素数が２以上１６以下のアルキレン基であることが好ましく、炭素数が２以上１２以下のアルキレン基であることがより好ましい。炭素数が上記の範囲内であることで、共重合体における親水部位と疎水部位が適切な距離に配置され、共重合体を顔料分散樹脂として用いた場合に良好な分散安定性を発現することができる。 -Structural unit represented by the general formula (1)-
The copolymer has a structural unit represented by the general formula (1).

In the structural unit represented by the general formula (1), R ₂ is a hydrogen atom or a methyl group. Further, L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms, preferably an alkylene group having 2 or more and 16 or less carbon atoms, and more preferably an alkylene group having 2 or more and 12 or less carbon atoms. .. When the number of carbon atoms is within the above range, the hydrophilic part and the hydrophobic part in the copolymer are arranged at an appropriate distance, and good dispersion stability is exhibited when the copolymer is used as a pigment dispersion resin. Can be done.

In the structural unit represented by the general formula (1), the naphthyl group having one end via the alkyl chain in the open end (open end, that is, the pendant structure portion) is a coloring material in the ink. It has excellent pigment adsorption power due to π-π stacking with a certain pigment.
As can be understood from the above description of "naphthyl group present at the end via the alkyl chain in the pendant", the structural unit represented by the general formula (1) typically hangs via the alkyl group. It may be the main chain of a copolymer having a pendant group such as a terminal naphthyl group. However, of course, it does not exclude the case where a part is included in the side chain.
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 a copolymer is used when preparing a pigment dispersion in which a pigment is dispersed in water, a naphthyl group is present at the end of the side chain of the copolymer, so that it is easily adsorbed on the pigment surface and is easily adhered to the pigment. Since the adsorption power is high, a pigment dispersion having high dispersibility and stable for a long period of time can be obtained.

The content of the structural unit represented by the general formula (1) in the copolymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is 60% by mass or more with respect to the total amount of the copolymer. 90% by mass or less is preferable. When the content is within this range, the ink is supplied to the inkjet head placed in a state where the protective cap that suppresses the drying of the ink on the nozzle surface of the inkjet head is not attached to the inkjet head (hereinafter referred to as a decap state). Therefore, when the ejection stability of the inkjet head is restored, the ejection recovery property can be further improved.

-Structural unit represented by general formulas (2) and (3)-
The copolymer substantially has at least one selected from the structural units represented by the general formula (2) and the general formula (3). Further, it is preferable that the copolymer substantially has a structural unit represented by the general formula (2) and a structural unit represented by the general formula (3).

一般式（２）で表される構造単位において、Ｒ_３は水素原子又はメチル基である。また、Ｌ_２は炭素数が２以上１２以下のアルキレン基、又はエーテル基を含み炭素数が４以上１２以下のアルキレン基である。 It is preferable that the copolymer substantially has a structural unit represented by the following general formula (2).

In the structural unit represented by the general formula (2), R ₃ is a hydrogen atom or a methyl group. Further, L ₂ is an alkylene group having 2 or more and 12 or less carbon atoms, or an alkylene group containing an ether group and having 4 or more and 12 or less carbon atoms.

Hereinafter, the structural unit represented by the general formula (2) will be illustrated, but the present application is not limited to the following specific examples.

一般式（３）で表される構造単位において、Ｒ_４は水素原子又はメチル基である。 It is preferable that the copolymer substantially has a structural unit represented by the following general formula (3).

In the structural unit represented by the general formula (3), _R4 is a hydrogen atom or a methyl group.

Hereinafter, the structural unit represented by the general formula (3) will be illustrated, but the present application is not limited to the following specific examples.

In addition to having the structural unit represented by the general formula (1), the copolymer is selected from at least a structural unit represented by the general formula (2) and a structural unit represented by the general formula (3). By substantially having one, it is possible to improve the ejection recovery property when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state. The mechanism is not clear, but it is presumed as follows.
It has a structural unit represented by the general formula (1), and further, at least one selected from the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is substantially used. The copolymer having in has a branched structure in the polymer main chain. Since the copolymer has a branched structure, it is possible to suppress the spread of the polymer chain even when the water content of the ink evaporates and the ink is concentrated, and it is possible to suppress a significant increase in the viscosity of the ink. Further, since the structural unit represented by the general formula (1) has a naphthyl group, the copolymer has excellent pigment adsorption power by π-π stacking with the pigment which is a coloring material in the ink, and also has excellent pigment adsorption power. A pigment dispersion containing a copolymer by having a urethane bond or a urea bond in the structural unit represented by the general formula (2) and the branched structural portion derived from the structural unit represented by the general formula (3). The affinity between the pigment and the polymer is improved, and the pigment is less likely to aggregate. In such a state, the ink containing the copolymer of the present embodiment is supplied with the ink when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head placed in the decapped state. When this is done, the pigment is easily redispersed, and the ejection recovery property can be improved.

In the present embodiment, the copolymer substantially has at least one selected from the structural units represented by the general formula (2) and the general formula (3), but "substantially having" is generally used. At least one of the mass of the structural unit represented by the formula (2) and the mass of the structural unit represented by the general formula (3) is 0.01% by mass or more with respect to the mass of the copolymer. Indicates that there is. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be improved.
Further, the total mass of the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is 0.01% by mass or more and 20.0% by mass with respect to the mass of the copolymer. It is preferably 0.1% by mass or more and 10.0% by mass or less. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be further improved.

Further, the total mass of the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is when the mass of the structural unit represented by the general formula (1) is 1. , 0.0001 or more and 0.2000 or less, more preferably 0.0006 or more and 0.1600 or less, particularly preferably 0.0010 or more and 0.0500 or less, and 0.0018 or more and 0. It is more preferably .0260 or less. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be further improved.

-Structural unit with anionic group-
The copolymer preferably has a structural unit having an anionic group. Hereinafter, structural units having an anionic group will be exemplified, but the present application is not limited to the following specific examples.

Structural units with anionic groups may be neutralized with a base. Examples of the base include sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium. Hydroxide, Triethylmethylammonium Hydroxide, Tributylmethylammonium Hydroxide, Trioctylmethylammonium Hydroxide, 2-Hydroxyethyltrimethylammonium Hydroxide, Tris (2-Hydroxyethyl) Methylammonium Hydroxide, propyltrimethylammonium Hydroxide, Hexyl Trimethylammonium hydroxide, octyltrimethylammonium hydroxide, nonyltrimethylammonium hydroxide, decyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octadecyltrimethylammonium hydroxide, di Dodecyldimethylammonium hydroxide, ditetradecyldimethylammonium hydroxide, dihexadecyldimethylammonium hydroxide, dioctadecyldimethylammonium hydroxide, ethylhexadecyldimethylammonium hydroxide, aqueous ammonia, dimethylamine, trimethylamine, monoethylamine, diethylamine, Triethylamine, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, dimethylethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, morpholin, N-methylmorphone, N-methyl-2- Examples thereof include pyrrolidone and 2-pyrrolidone.
The base as a neutralizing agent may be used alone or in combination of two or more.
The neutralization treatment may be carried out when the monomer having an anionic group is copolymerized or when the copolymer is dissolved.

一般式（４）で表される構造単位において、Ｒ_１は水素原子又はメチル基である。また、Ｘは水素原子又は陽イオンである。
陽イオンの場合、陽イオンに隣接する酸素はＯ^－として存在する。陽イオンとしては、ナトリウムイオン、カリウムイオン、リチウムイオン、テトラメチルアンモニウムイオン、テトラエチルアンモニウムイオン、テトラプロピルアンモニウムイオン、テトラブチルアンモニウムイオン、テトラペンチルアンモニウムイオン、テトラヘキシルアンモニウムイオン、トリエチルメチルアンモニウムイオン、トリブチルメチルアンモニウムイオン、トリオクチルメチルアンモニウムイオン、２－ヒドロキシエチルトリメチルアンモニウムイオン、トリス（２－ヒドロキシエチル）メチルアンモニウムイオン、プロピルトリメチルアンモニウムイオン、ヘキシルトリメチルアンモニウムイオン、オクチルトリメチルアンモニウムイオン、ノニルトリメチルアンモニウムイオン、デシルトリメチルアンモニウムイオン、ドデシルトリメチルアンモニウムイオン、テトラデシルトリメチルアンモニウムイオン、ヘキサデシルトリメチルアンモニウムイオン、オクタデシルトリメチルアンモニウムイオンジドデシルジメチルアンモニウムイオン、ジテトラデシルジメチルアンモニウムイオン、ジヘキサデシルジメチルアンモニウムイオン、ジオクタデシルジメチルアンモニウムイオン、エチルヘキサデシルジメチルアンモニウムイオン、アンモニウムイオン、ジメチルアンモニウムイオン、トリメチルアンモニウムイオン、モノエチルアンモニウムイオン、ジエチルアンモニウムイオン、トリエチルアンモニウムイオン、モノエタノールアンモニウムイオン、ジエタノールアンモニウムイオン、トリエタノールアンモニウムイオン、メチルエタノールアンモニウムイオン、メチルジエタノールアンモニウムイオン、ジメチルエタノールアンモニウムイオン、モノプロパノールアンモニウムイオン、ジプロパノールアンモニウムイオン、トリプロパノールアンモニウムイオン、イソプロパノールアンモニウムイオン、モルホリニウムイオン、Ｎ－メチルモルホリニウムイオン、Ｎ－メチル－２－ピロリドニウムイオン、２－ピロリドニウムイオンなどが挙げられる。 Further, the structural unit having an anionic group is more preferably a structural unit represented by the following general formula (4).

In the structural unit represented by the general formula (4), R ₁ is a hydrogen atom or a methyl group. Further, X is a hydrogen atom or a cation.
In the case of cations, the oxygen adjacent to the cation exists as O ⁻ . The cations include sodium ion, potassium ion, lithium ion, tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, triethylmethylammonium ion, and tributylmethyl. Ammonium ion, trioctylmethylammonium ion, 2-hydroxyethyltrimethylammonium ion, tris (2-hydroxyethyl) methylammonium ion, propyltrimethylammonium ion, hexyltrimethylammonium ion, octyltrimethylammonium ion, nonyltrimethylammonium ion, decyltrimethyl Ammonium ion, dodecyltrimethylammonium ion, tetradecyltrimethylammonium ion, hexadecyltrimethylammonium ion, octadecyltrimethylammonium ion didodecyldimethylammonium ion, ditetradecyldimethylammonium ion, dihexadecyldimethylammonium ion, dioctadecyldimethylammonium ion, Ethylhexadecyldimethylammonium ion, ammonium ion, dimethylammonium ion, trimethylammonium ion, monoethylammonium ion, diethylammonium ion, triethylammonium ion, monoethanolammonium ion, diethanolammonium ion, triethanolammonium ion, methylethanolammonium ion, Methyldiethanolammonium ion, dimethylethanolammonium ion, monopropanolammonium ion, dipropanolammonium ion, tripropanolammonium ion, isopropanolammonium ion, morpholinium ion, N-methylmorpholinium ion, N-methyl-2-pyrrolidoni Ammonium ion, 2-pyrrolidnium ion and the like can be mentioned.

The content of the structural unit having an anionic group in the copolymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is 10% by mass or more and 40% by mass or less with respect to the copolymer. It is preferable to have. When the content is within this range, the ejection recovery property can be further improved when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head placed in the decapped state.

-Other structural units-
The copolymer can have a structural unit composed of other polymerizable monomers, if necessary, in addition to the structural units represented by the above general formulas (1) to (3). The other polymerizable monomer can be appropriately selected depending on the intended purpose, and examples thereof include a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, and a polymerizable surfactant.

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, lauryl (meth) acrylate (C12), tridecyl (meth) acrylate (C13), (meth) ) Tetradecyl acrylate (C14), (meth) pentadecyl acrylate (C15), (meth) hexadecyl acrylate (C16), (meth) heptadecyl acrylate (C17), (meth) nonadecil acrylate (C19), (meth) ) Eikosyl acrylate (C20), Henicosyl (meth) acrylate (C21), Dococil (meth) acrylate (C22) and other (meth) alkyl (meth) acrylates; 1-hexene, 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, Examples thereof include unsaturated ethylene monomers having an alkyl group such as 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene and 1-dococene. These may be used alone or in combination of two or more.

Examples of the polymerizable hydrophilic monomer include (meth) acrylic acid-2-hydroxyethyl, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and polyethylene glycol mono. (Meta) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, N, N-dimethylacrylamide, Nt-butylacrylamide, N Examples thereof include nonionic unsaturated ethylene monomers such as octylacrylamide and Nt-octylacrylamide.

Other polymerizable monomers may be used alone or in admixture of two or more. In addition, other polymerizable monomers should be used in an amount of 5% by mass or more and 100% by mass or less with respect to the total amount of each monomer forming the structural units represented by the above general formulas (1) to (3). Is preferable.

-Method for synthesizing copolymer-
The copolymer of the present embodiment contains a monomer represented by the general formula (5), and is further selected from a monomer represented by the general formula (6) and a monomer represented by the general formula (7). It is synthesized through a polymerization step of polymerizing a polymerizable material substantially containing at least one. Further, the polymerizable material may contain a monomer having an anionic group or the like, if necessary. In addition to the polymerization step, the step of synthesizing the copolymer may include other steps such as a neutralization step, if necessary.

一般式（５）で表されるモノマーにおいて、Ｒ_２は水素原子又はメチル基である。また、Ｌ_１は炭素数が２以上１８以下のアルキレン基であり、炭素数が２以上１６以下のアルキレン基であることが好ましく、炭素数が２以上１２以下のアルキレン基であることがより好ましい。 --- Monomer represented by the general formula (5) ---
The polymerizable material preferably contains a monomer represented by the general formula (5). The structural unit represented by the general formula (1) is formed by copolymerizing the monomer represented by the general formula (5).

In the monomer represented by the general formula (5), R ₂ is a hydrogen atom or a methyl group. Further, L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms, preferably an alkylene group having 2 or more and 16 or less carbon atoms, and more preferably an alkylene group having 2 or more and 12 or less carbon atoms. ..

Hereinafter, the monomer represented by the general formula (5) will be illustrated, but the present application is not limited to the following specific examples.

反応式（１）、及び反応式（２）において、Ｒ_２は水素原子又はメチル基である。また、Ｌ_１は炭素数が２以上１８以下のアルキレン基であり、炭素数が２以上１６以下のアルキレン基であることが好ましく、炭素数が２以上１２以下のアルキレン基であることがより好ましい。 As shown in the following reaction formulas (1) and reaction formula (2), the monomer represented by the general formula (5) first contains naphthalenecarbonyl chloride (R-1) and an excess amount of the diol compound (R-). 2) is subjected to a condensation reaction in the presence of an acid accepting agent such as amine or pyridine to obtain a naphthalenecarboxylic acid hydroxyalkyl ester (R-3). Then, 2-isocyanatoethyl (meth) acrylate (R-4) and naphthalene carboxylic acid hydroxyalkyl ester (R-3) can be reacted to obtain a monomer (M5).

In the reaction formula (1) and the reaction formula (2), R ₂ is a hydrogen atom or a methyl group. Further, L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms, preferably an alkylene group having 2 or more and 16 or less carbon atoms, and more preferably an alkylene group having 2 or more and 12 or less carbon atoms. ..

The content of the monomer represented by the general formula (5) in the polymerizable material is not particularly limited and may be appropriately selected depending on the intended purpose, but is 60% by mass or more and 90% by mass or more with respect to the total amount of the polymerizable material. It is preferably mass% or less. When the content is within this range, the ejection recovery property can be further improved when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head placed in the decapped state.

一般式（６）で表されるモノマーにおいて、Ｒ_３は水素原子又はメチル基である。また、Ｌ_２は炭素数が２以上１２以下のアルキレン基、又はエーテル基を含み炭素数が４以上１２以下のアルキレン基である。 --- Monomer represented by the general formula (6) ---
The polymerizable material preferably contains a monomer represented by the following general formula (6). The structural unit represented by the general formula (2) is formed by copolymerizing the monomer represented by the general formula (6).

In the monomer represented by the general formula ( ₆ ), R3 is a hydrogen atom or a methyl group. Further, L ₂ is an alkylene group having 2 or more and 12 or less carbon atoms, or an alkylene group containing an ether group and having 4 or more and 12 or less carbon atoms.

Hereinafter, the monomer represented by the general formula (6) will be illustrated, but the present application is not limited to the following specific examples.

反応式（３）において、Ｒ_３は水素原子又はメチル基である。また、Ｌ_２は炭素数が２以上１２以下のアルキレン基、又はエーテル基を含み炭素数が４以上１２以下のアルキレン基である。 The monomer represented by the general formula (6) is obtained by reacting the diol compound (R-2) with the 2-isocyanatoethyl (meth) acrylate (R-4) as shown in the reaction formula (3) below. The monomer (M6) can be obtained.

In reaction equation (3), R ₃ is a hydrogen atom or a methyl group. Further, L ₂ is an alkylene group having 2 or more and 12 or less carbon atoms, or an alkylene group containing an ether group and having 4 or more and 12 or less carbon atoms.

The monomer represented by the above general formula (6) can also be obtained as a by-product when synthesizing the monomer represented by the general formula (5). Therefore, when a crude product of the monomer represented by the general formula (5) containing the monomer represented by the general formula (6) as a by-product is used for producing the copolymer, the general formula (2) is used. A copolymer containing the structural unit to be obtained is obtained.
However, in general, in the process of synthesizing the monomer represented by the general formula (5), the naphthalenecarboxylic acid hydroxyalkyl ester (R-3) is purified by silica gel column chromatography or the like and is represented by the general formula (5). The diol compound (R-2), which is the raw material of the monomer, is removed. Therefore, when a purified product of naphthalenecarboxylic acid hydroxyalkyl ester (R-3) is used to prepare a monomer represented by the general formula (5), a polymerizable material containing the monomer represented by the general formula (5). It does not substantially contain the monomer represented by the general formula (6). Specifically, the content of the monomer represented by the general formula (6) does not exceed 0.01% by mass with respect to the total amount of the polymerizable material.
On the other hand, the polymerizable material in the present embodiment substantially contains at least one selected from the monomer represented by the general formula (6) and the monomer represented by the general formula (7). When the polymerizable material contains a monomer represented by the general formula (6), "substantially contained" means that the mass of the monomer represented by the general formula (6) is relative to the mass of the polymerizable material. Indicates that it is 0.01% by mass or more. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be improved.

The monomer represented by the general formula (6) may be contained as a by-product in synthesizing the monomer represented by the general formula (5) as described above, and may be contained as a by-product of the separately synthesized general formula (6). ) May be used for the synthesis of the copolymer. When the monomer represented by the general formula (6) is contained as a by-product in the monomer represented by the general formula (5), the monomer represented by the general formula (6) is represented by the general formula (5). The content thereof can be adjusted, for example, by adjusting the residual amount of the diol compound (R-2) as a reaction raw material after the synthesis of the naphthalene carboxylic acid hydroxyalkyl ester (R-3).

一般式（７）で表されるモノマーにおいて、Ｒ_４は水素原子又はメチル基である。 --- Monomer represented by the general formula (7) ---
The polymerizable material preferably contains a monomer represented by the following general formula (7). The structural unit represented by the general formula (3) is formed by copolymerizing the monomer represented by the general formula (7).

In the monomer represented by the general formula (7), _R4 is a hydrogen atom or a methyl group.

Hereinafter, the monomer represented by the general formula (7) will be illustrated, but the present application is not limited to the following specific examples.

反応式（４）において、Ｒ_４は水素原子又はメチル基である。 As shown in the following reaction formula (4), the monomer represented by the general formula (7) is a monomer by reacting water with 2-isocyanatoethyl (meth) acrylate (R-4) and decarboxylating the monomer. (M7) can be obtained.

In reaction equation (4), _R4 is a hydrogen atom or a methyl group.

The monomer represented by the above general formula (7) can also be obtained as a by-product when synthesizing the monomer represented by the general formula (5). Therefore, when a crude product of the monomer represented by the general formula (5) containing the monomer represented by the general formula (7) as a by-product is used for producing the copolymer, the general formula (3) is used. A copolymer containing the structural unit to be obtained is obtained.
However, in general, the monomer represented by the general formula (7) is purified and removed by silica gel column chromatography or the like in the process of synthesizing the monomer represented by the general formula (5). Therefore, the polymerizable material containing the monomer represented by the general formula (5) does not substantially contain the monomer represented by the general formula (7). Specifically, the content of the monomer represented by the general formula (7) does not exceed 0.01% by mass with respect to the total amount of the polymerizable material.
On the other hand, the polymerizable material in the present embodiment substantially contains at least one selected from the monomer represented by the general formula (6) and the monomer represented by the general formula (7). When the polymerizable material contains a monomer represented by the general formula (7), "substantially contained" means that the mass of the monomer represented by the general formula (7) is relative to the mass of the polymerizable material. Indicates that it is 0.01% by mass or more. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be improved.

The monomer represented by the general formula (7) in the present embodiment may be contained as a by-product in synthesizing the monomer represented by the general formula (5) as described above, and is separately synthesized. The monomer represented by the general formula (7) may be used for the synthesis of the copolymer. When the monomer represented by the general formula (7) is contained as a by-product in the monomer represented by the general formula (5), the monomer represented by the general formula (7) is represented by the monomer represented by the general formula (5). The content in the medium can be adjusted, for example, by adjusting the residual amount of water after the synthesis of the naphthalene carboxylic acid hydroxyalkyl ester (R-3).

Further, the total mass of the monomer represented by the general formula (6) and the monomer represented by the general formula (7) is 0.01% by mass or more and 20.0% by mass or less with respect to the mass of the polymerizable material. It is preferably 0.1% by mass or more and 10.0% by mass or less, and further preferably 0.1% by mass or more and 4.0% by mass or less. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be further improved.

Further, the total mass of the monomer represented by the general formula (6) and the monomer represented by the general formula (7) is 0. When the mass of the monomer represented by the general formula (5) is 1. It is preferably 0001 or more and 0.2000 or less, more preferably 0.0006 or more and 0.1600 or less, particularly preferably 0.0010 or more and 0.0500 or less, and 0.0018 or more and 0.0260 or less. Is more preferable. Within this range, when the ejection stability of the inkjet head is restored by supplying ink to the inkjet head placed in the decapped state, the ejection recovery property can be further improved.

--Monomer with anionic group ---
The polymerizable material preferably contains a monomer having an anionic group. The structural unit having an anionic group is formed by copolymerizing a monomer having an anionic group. Examples of the monomer having an anionic group include an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer.
Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like. Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid and 2-acrylamide-2-methylpropane sulfonic acid. Examples of the unsaturated phosphoric acid monomer include vinylphosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and dibutyl-2-acry. Examples thereof include leuroxyethyl phosphate.
Among these, a monomer having a carboxyl group is preferable, and acrylic acid or methacrylic acid is more preferable, from the viewpoint of storage stability. The structural unit represented by the above general formula (4) is formed through a step of copolymerizing acrylic acid or methacrylic acid.
Further, the monomer having an anionic group may be used alone or in combination of two or more.

The content of the monomer having an anionic group in the polymerizable material is not particularly limited and may be appropriately selected depending on the intended purpose, but is 10% by mass or more and 40% by mass or less with respect to the polymerizable material. Is preferable. When the content is within this range, the ejection recovery property can be further improved when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head placed in the decapped state.

－－Polymerization process －－
As a polymerization step for producing a copolymer by polymerizing a polymerizable material, a method using a radical polymerization initiator is preferable because it is easy to carry out a polymerization operation and adjust the molecular weight, and a solution polymerization method in which a polymerization reaction is carried out in a solution. Is even more preferable.
Preferred solvents for radical polymerization by the solution polymerization method are ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, acetate solvents such as ethyl acetate and butyl acetate, and aromatic carbonization such as benzene, toluene and xylene. Examples thereof include a hydrogen-based solvent, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethylsulfoxide and hexamethylphosphoamide, and more preferably, a ketone-based solvent, an acetate ester-based solvent and an alcohol-based solvent.
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, peroxyester, cyano-based azobisisobutyronitrile, and azobis (2-methylbutyronitrile). Examples thereof include azobis (2,2'-isovaleronitrile), non-cyano dimethyl-2,2'-azobisisobutyrate, and the like. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable, because the molecular weight can be easily controlled and the decomposition temperature is low.
The content of the radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 to 10% by mass with respect to the total amount of the polymerizable monomer. Chain transfer agents may be added in appropriate amounts to adjust the molecular weight of the polymer.
Examples of chain transfer agents include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecyl mercaptan, 1-dodecanethiol, thioglycerol, and the like.
The polymerization temperature is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 ° C to 150 ° C, more preferably 60 ° C to 100 ° C. The polymerization time is also not particularly limited and may be appropriately selected depending on the intended purpose, but 3 to 48 hours is preferable.

－－Neutralization process－－
The base as a neutralizing agent may be used alone or in combination of two or more.
The neutralization step may be performed when copolymerizing with a monomer having an anionic group, or may be performed when dissolving the copolymer.

-Molecular weight of copolymer-
The weight average molecular weight of the copolymer is preferably 5000 or more and 40,000 or less in terms of polystyrene. More preferably, it is 15,000 or more and 30,000 or less. When the weight average molecular weight is in this range, the ejection recovery property can be further improved when the ejection stability of the inkjet head is restored by supplying the ink to the inkjet head placed in the decapped state.

-Analysis method of structural units represented by the general formulas (2) and (3) in the copolymer-
For the structural units represented by the general formulas (2) and (3) in the copolymer, the copolymer is separated and extracted from the ink as necessary, and a general analysis method such as NMR or IR is used. It can be analyzed by doing so.

-Amount of copolymer added-
The content of the copolymer in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but the solid content is preferably 0.05% by mass or more and 10% by mass or less, preferably 0.3% by mass or more. More preferably, it is 5% by mass or less. When the content is 0.05% by mass or more, the dispersibility and storage stability are improved, and when it is 10% by mass or less, it becomes easy to set the viscosity range suitable for ejecting ink from the head.
The use of the copolymer is not particularly limited, and it can be used as a dispersant for pigments or as an additive to pigment dispersions. When used as a dispersant for pigments, improvement in storage stability is observed even in inks having a high content of water-soluble organic solvents.
The content of the copolymer is not particularly limited when used as a pigment dispersant, and can be appropriately selected depending on the intended purpose. With respect to 100 parts by mass of the pigment, 1 part by mass to 100 parts by mass is preferable, and 5 parts by mass to 80 parts by mass is more preferable. When the content is within this range, it is advantageous in that the image density and storage stability are good.

<Organic solvent>
The organic solvent that can be used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 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-hexanediol, ethyl-1,2,4-butanediol, 1,2,3-butanetriol, 2,2,4-trimethyl- Examples thereof include 1,3-pentanediol and petriol.
Examples of polyhydric alcohol alkyl ethers include 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.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Can be mentioned.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine and the like.
Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol.
Examples of other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

As the organic solvent, 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 the glycol ether compound 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; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

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

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

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % Or more and 60% by mass or less are more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used as the pigment.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy color pigment such as gold or silver, a metallic pigment, or the like can be used.
As inorganic pigments, carbon black produced by known methods such as contact method, furnace method, thermal method, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Mengara), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As a dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1,2,24,94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1,2,15,71,86,87,98,165,199,202, C.I. I. Dilekdo Black 19,38,51,71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoint of improving the image density, good fixing property and ejection stability. It is as follows.

As a method of dispersing the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a method of dispersing using a dispersant are used. The method, etc. can be mentioned.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) so that the pigment can be dispersed in water. Can be mentioned.
Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonic acid Na formalin condensate can also be suitably used as the dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but is 0.1% by mass from the viewpoint of obtaining good ejection stability and increasing the image density. 50% by mass or more is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
It is preferable to degas the pigment dispersion by filtering the coarse particles with a filter, a centrifuge, or the like, if necessary.

<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-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Of these, those that do not decompose even at high pH are preferable. Examples of the silicone-based surfactant include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as the modifying 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 compounds in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a poly having a perfluoroalkyl ether group in the side chain. Examples thereof include salts of oxyalkylene ether polymers. The counter ions 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 , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
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. For example, side-chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side chain. Examples thereof include both-terminal modified polydimethylsiloxane, and a polyether-modified silicone-based surfactant having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as modifying groups is particularly preferable because it exhibits good properties as an aqueous surfactant. ..
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above-mentioned polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) is dimethylpoly. Examples thereof include those introduced into the Si part side chain 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.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shinetsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Nippon 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.) and the like can be 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。

上記一般式（Ｆ－２）で表される化合物において、ＹはＨ、又はＣｍＦ_２ｍ＋１でｍは１～６の整数、又はＣＨ_２ＣＨ（ＯＨ）ＣＨ_２－ＣｍＦ_２ｍ＋１でｍは４～６の整数、又はＣｐＨ_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。 As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and 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.

In the compound represented by the above general formula (F-2), Y is H or CmF _{2m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ -CmF _{2m + 1} and m is 4 to 6. It is an integer, or CpH _{2p + 1} and p is an integer of 1 to 19. n is an integer of 1 to 6. a is an integer of 4 to 14.
Commercially available products 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, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); 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 The Chemours Company); 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 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries Co., Ltd.) Among these, FS-3100, FS-34, FS- of The Chemours Co., Ltd. from the viewpoint of remarkably improving good print quality, particularly color development, permeability to paper, wettability, and leveling property. 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omninova, and Unidyne DSN-manufactured by Daikin Industries Co., Ltd. 403N is particularly preferable.

The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of excellent wettability and ejection stability and improvement in image quality, 0.001 mass is used. % Or more and 5% by mass or less are preferable, and 0.05% by mass or more and 5% by mass or less are more preferable.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

<Preservatives and fungicides>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one and the like.

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

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

<< Ink manufacturing method >>
As a method for producing ink, for example, water, a coloring material, a copolymer, and other components are dispersed or dissolved in an aqueous medium after the copolymer is prepared according to the above-mentioned copolymer synthesis method. Examples thereof include a method of producing by stirring and mixing. Further, the copolymer may be used as a color material dispersion resin used when producing a color material dispersion.
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 by, for example, 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, transparency sheet, and general-purpose printing paper.

<< Recorded material >>
The recording material has a recording medium and a print layer formed by the ink of the present embodiment applied on the recording medium. Since the printing layer is a layer formed by applying the ink of the present embodiment and drying it, it contains the above-mentioned copolymer.

<< Ink container >>
The ink container may include an ink accommodating portion for accommodating the ink of the present embodiment, and may further have other members appropriately selected as necessary.
The shape, structure, size, material, etc. of the ink container can be appropriately selected according to the purpose. For example, an ink container having an ink container made of an aluminum laminate film, a resin film, or the like, or having a large capacity. An ink tank or the like is suitable.

<< Recording device, recording method >>
The ink of the present invention can be suitably used for various recording devices by an inkjet recording method, for example, a printer, a facsimile device, a copying device, a printer / fax / copier multifunction device, a three-dimensional modeling device, and the like.
In the present invention, the recording device and the recording method are devices capable of ejecting ink, various processing liquids, and the like to a recording medium, and a method of recording using the device. The recording medium means a medium to which ink and various treatment liquids can adhere even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means related to feeding, transporting, and discharging paper of a recording medium, a pretreatment device, a device called a posttreatment device, and the like. ..
The recording device and recording method may include 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 printed surface and the back surface of the recording medium. The heating means and the drying means are not particularly limited, but for example, a hot air heater and 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 significant images such as characters and figures are visualized by ink. For example, those that form patterns such as geometric patterns and those that form three-dimensional images are also included.
Further, the recording device includes both a serial type device that moves the discharge head and a line type device that does not move the discharge head, unless otherwise specified.
Further, as this recording device, it is possible to use not only a desktop type but also a wide recording device capable of printing on an A0 size recording medium, or, for example, continuous paper wound in a roll shape as a recording medium. A continuous book printer is also included.
An example of the recording device will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective explanatory 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 portion 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage section 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is, for example, a package of an aluminum laminated film or the like. It is formed of members. The ink container 411 is housed in, for example, a plastic container case 414. 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 behind the opening when the cover 401c of the main body of the apparatus is opened. A main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink ejection port 413 of the main tank 410 and the ejection head 434 for each color communicate with each other via the supply tube 436 for each color, and ink can be ejected from the ejection head 434 to the recording medium.

The method of using the ink is not limited to the inkjet recording method, and can be widely used. In addition to the inkjet recording method, examples thereof include 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, and a spray coating method.

<< Use >>
The use of the ink of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose, and can be applied to, for example, printed matter, paints, coating materials, base materials and the like. Further, it can be used not only as an ink to form two-dimensional characters and images, but also as a three-dimensional modeling material for forming a three-dimensional stereoscopic image (three-dimensional model).
As the three-dimensional modeling apparatus for modeling the three-dimensional object, a known one can be used, and is not particularly limited, but for example, an apparatus provided with ink accommodating means, supply means, ejection means, drying means and the like is used. be able to. The three-dimensional model includes a three-dimensional model obtained by overcoating with ink. Further, a molded product obtained by processing a structure in which ink is applied on a base material such as a recording medium is also included. The molded product is, for example, a recorded material or structure formed in a sheet shape or a film shape, which has been subjected to molding processing such as heat stretching or punching. It is suitably used for molding after decorating the surface of electronic devices, meters of cameras, panels of operation parts, and the like.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

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

<Synthesis example of monomer represented by general formula (5)>
-Synthesis of M5-3-
62.0 g (525 mmol) of 1,6-hexanediol (manufactured by Tokyo Kasei Co., 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 Co., Ltd.) in 100 mL of methylene chloride was added dropwise to this solution with stirring over 2 hours, and then the mixture was stirred at room temperature for 6 hours. .. After washing the obtained reaction solution 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 98/2) as an eluent to obtain 52.5 g of 2-naphthoic acid-2-hydroxyethyl ester.

Next, 42.1 g (155 mmol) of 2-naphthoic acid-2-hydroxyethyl ester was dissolved in 80 mL of dry methyl ethyl ketone and heated to 60 ° C. A solution of 24.0 g (155 mmol) of 2-methacryloyloxyethyl isocyanate (Kalens MOI, manufactured by Showa Denko KK) dissolved in 20 mL of dry methyl ethyl ketone was added dropwise to this solution with stirring over 1 hour, and then at 70 ° C. Was stirred for 12 hours. After cooling to room temperature, the solvent was distilled off. The residue is purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent, and 57.0 g of the monomer represented by the general formula (5) is M5-. I got 3.

-Synthesis of M5-1-
M5-1, which is a monomer represented by the general formula (5), is used in the same manner as in the synthesis of M5-3, except that ethylene glycol (manufactured by Tokyo Kasei Co., Ltd.) is used instead of 1,6-hexanediol. Obtained.

-Synthesis of M5-6-
It is a monomer represented by the general formula (5) in the same manner as the synthesis of M5-3, except that 1,12-dodecanediol (manufactured by Tokyo Kasei Co., Ltd.) is used instead of 1,6-hexanediol. Obtained M5-6.

<Synthesis example of monomer represented by general formula (6)>
-Synthesis of M6-3-
59.4 g (500 mmol) of 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of methyl ethyl ketone, and 0.03 g (0.05 mmol) of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A solution prepared by dissolving 155.2 g (1000 mmol) of 2-isocyanatoethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 300 mL of methyl ethyl ketone was added dropwise to this solution with stirring over 1 hour, and then at 40 ° C. for 3 hours. It was reacted. After distilling off the solvent from the obtained reaction solution, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and the general formula (190.5 g) was used. M6-3, which is a monomer represented by 6), was obtained.

-Synthesis of M6-8-
59.4 g (500 mmol) of 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 84.1 g (1000 mmol) of 3,4-dihydro-2H-pyran (manufactured by Tokyo Chemical Industry Co., Ltd.) in 700 mL of toluene. It was dissolved and stirred at room temperature. To this solution, 0.17 g (1.0 mmol) of p-toluenesulfonic acid monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 30 ° C. for 3 hours. The reaction solution was mixed with an aqueous sodium hydrogen carbonate solution. After neutralization and washing with water twice, the organic phase was isolated, magnesium sulfate was added, and the mixture was stirred and allowed to stand. Magnesium sulfate was filtered off, and then the solvent was distilled off by an evaporator. Then, as an eluent. Purification by silica gel column chromatography using a mixed solvent of n-hexane / ethyl acetate (volume ratio 4/1) gave 62.7 g of M6-8 intermediate 1 represented by the following structural formula 1.

68.3 g (500 mmol) of 1-chloro-6-hexanol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 63.1 g (750 mmol) of 3,4-dihydro-2H-pyran (manufactured by Tokyo Chemical Industry Co., Ltd.) in 250 mL of dichloromethane. It was dissolved and stirred at room temperature. To this solution, 0.17 g (1.0 mmol) of p-toluenesulfonic acid monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 30 ° C. for 2 hours. The reaction solution was mixed with an aqueous sodium hydrogen carbonate solution. After neutralization and washing with water twice, the organic phase was isolated, magnesium sulfate was added, and the mixture was stirred and allowed to stand. Magnesium sulfate was filtered off, and then the solvent was distilled off by an evaporator. Then, as an eluent. Purification by silica gel column chromatography using a mixed solvent of n-hexane / ethyl acetate (volume ratio 1/1) gave 76.1 g of M6-8 intermediate 2 represented by the following structural formula 2.

50.5 g (250 mmol) of M6-8 Intermediate 1 was dissolved in 200 mL of N, N-dimethylformamide. To this solution was added 20 g (500 mmol) sodium hydride 60% liquid paraffin dispersion (manufactured by Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at room temperature. Then, a solution prepared by dissolving 55.0 g (250 mmol) of M6-8 in Intermediate 2 in 100 mL of N, N-dimethylformamide was added dropwise over 15 minutes. After stirring at room temperature for 2 hours, the reaction solution was poured into water, and washing with water was repeated twice. After isolating the organic phase and distilling off the solvent with an evaporator, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and 57.9 g of the following was purified. An intermediate 3 of M6-8 represented by the structural formula 3 was obtained.

38.6 g (100 mmol) of M6-8 Intermediate 3 was dissolved in 200 mL of tetrahydrofuran. 115.8 g of a 3M aqueous hydrochloric acid solution was added dropwise to this solution over 15 minutes with stirring at room temperature, and the mixture was stirred at room temperature for 2 hours. The reaction solution was neutralized with an aqueous sodium hydrogen carbonate solution, washed with water twice, and then the organic phase was isolated and the solvent was distilled off by an evaporator. Then, using an n-hexane / methyl ethyl ketone (volume ratio 1/1) mixed solvent as an eluent, the product was purified by silica gel column chromatography, and 12.9 g of the intermediate 4 of M6-8 represented by the following structural formula 4 was used. Got

10.9 g (50 mmol) of M6-8 Intermediate 4 was dissolved in 30 mL of methyl ethyl ketone, and 0.003 g (0.005 mmol) of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A solution prepared by dissolving 15.5 g (100 mmol) of 2-isocyanatoethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 30 mL of methyl ethyl ketone was added dropwise to this solution over 10 minutes with stirring, and then at 40 ° C. for 3 hours. It was reacted. After distilling off the solvent from the obtained reaction solution, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and the general formula (20.8 g) was used. M6-8, which is the monomer represented by 6), was obtained.

-Synthesis of M6-1-
31.0 g (500 mmol) of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 150 mL of methyl ethyl ketone, and 0.03 g (0.05 mmol) of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A solution prepared by dissolving 141.1 g (1000 mmol) of 2-isocyanatoethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 300 mL of methyl ethyl ketone was added dropwise to this solution with stirring over 1 hour, and then at 40 ° C. for 3 hours. It was reacted. After distilling off the solvent from the obtained reaction solution, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and the general formula (134.2 g) was used. M6-1 which is a monomer represented by 6) was obtained.

-Synthesis of M6-6-
42.5 g (400 mmol) of diethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of methyl ethyl ketone, and 0.03 g (0.05 mmol) of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A solution prepared by dissolving 124.1 g (800 mmol) of 2-isocyanatoethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 300 mL of methyl ethyl ketone was added dropwise to this solution with stirring over 1 hour, and then at 40 ° C. for 3 hours. It was reacted. After distilling off the solvent from the obtained reaction solution, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and the general formula (126.5 g) was used. M6-6, which is the monomer represented by 6), was obtained.

-Synthesis of M6-5-
50.6 g (250 mmol) of 1,12-dodecanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of methyl ethyl ketone, and 0.03 g (0.05 mmol) of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A solution prepared by dissolving 77.6 g (500 mmol) of 2-isocyanatoethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 150 mL of methyl ethyl ketone was added dropwise to this solution with stirring over 1 hour, and then at 40 ° C. for 3 hours. It was reacted. After distilling off the solvent from the obtained reaction solution, the mixture was purified by silica gel column chromatography using an n-hexane / ethyl acetate (volume ratio 2/1) mixed solvent as an eluent, and the general formula (109.3 g) was used. M6-5, which is the monomer represented by 6), was obtained.

<Synthesis example of monomer represented by general formula (7)>
-Synthesis of M7-1-
155.2 g (1000 mmol) of 2-isocyanatoethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 300 mL of methyl ethyl ketone, 19.8 g of ion-exchanged water and 0.03 g (0.05 mmol) of dibutyltin dilaurate (Tokyo Chemical Industry). (Made by Kogyo Co., Ltd.) was added. The mixture was stirred at room temperature for 2 hours and at 40 ° C. for another 2 hours. After filtering the reaction solution, the solvent was distilled off by an evaporator. Next, using a mixed solvent of methylene chloride / methanol (volume ratio 4/1) as an eluent, purification was performed by silica gel column chromatography to obtain 129.3 g of M7-1, which is a monomer represented by the general formula (7). Obtained.

<Example of synthesis of copolymer>
-Synthesis of copolymer CP-1-
14.4 g (200 mmol) of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 85.5 g (200 mmol) of monomer M5-3, and 0.05 g (0.12 mmol) of monomer M6-3 are dissolved in 500 ml of dry methyl ethyl ketone. To prepare a monomer solution. After heating 10% by mass of the monomer solution to 75 ° C. under an argon stream, 4.5 g of 2,2'-azobis (isobutyronitrile) (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.) is dissolved in the remaining monomer solution. The solution was added dropwise over 2 hours and 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 96.4 g of [Copolymer CP-1] (weight average molecular weight (Mw): 19000).

-Synthesis of copolymers CP-2 to 7 and RCP-1 to 2-
In the synthesis of the copolymer CP-1, the same as the synthesis of the copolymer CP-1 except that the polymerizable material, the polymerization initiator, the chain transfer agent, and the polymerization temperature were changed as shown in Table 1 below. , Copolymers CP-2 to 7 and RCP-1 to 2 were prepared.

In Table 1, other monomers, monomers having an anionic group, and chain transfer agents are as follows.
-Other monomers (bifunctional acrylate A-HD-N, manufactured by Shin Nakamura Chemical Industry Co., Ltd., 1.1 g (4.9 mmol))
・ AA (acrylic acid, manufactured by Tokyo Chemical Industry Co., Ltd.)
・ MAA (methacrylic acid, manufactured by Tokyo Chemical Industry Co., Ltd.)
・ Chain transfer agent (α-thioglycerol, manufactured by Tokyo Chemical Industry Co., Ltd.)

<Example of adjusting pigment dispersion>
-Adjustment of pigment dispersion PD-1-
4.0 parts of the copolymer CP-1 was dissolved in 76.0 parts of a diethanolamine aqueous solution so that the pH was 8.0. To 80.0 parts of the obtained copolymer aqueous solution, 20.0 parts of Pigment Red 122 (Toner Magenta EO02, manufactured by Clariant) 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 (manufactured by Simmal Enterprises, KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size. 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: 20% by mass).

-Adjustment of pigment dispersions PD-2 to 10 and RPD-1 to 2-
In the adjustment of the pigment dispersion PD-1, the pigment dispersions PD-2 to 10 and RPD-1 to the same as the adjustment of the pigment dispersion PD-1 except that the composition was changed as shown in Table 2 below. 2 was produced.

In Table 2, the neutralizing agent and the pigment are as follows.
・ DEA (diethanolamine, manufactured by Kanto Chemical Co., Inc.)
・ KOH (potassium hydroxide, manufactured by Kishida Chemical Co., Ltd.)
・ NaOH (sodium hydroxide, manufactured by Kishida Chemical Co., Ltd.)
・ Carbon black (NIPEX150, manufactured by Orion Engineered Carbons)
・ Pigment Blue 15: 3 (Chromofine Blue A-220JC, manufactured by Dainichiseika Co., Ltd.)
・ Pigment Yellow 74 (First Yellow 531; manufactured by Dainichiseika Co., Ltd.)

<Ink adjustment example>
(Example 1)
-Making ink GJ-1-
40.0 parts by mass of pigment dispersion PD-1, 10.0 parts by mass of glycerin, 5.0 parts by mass of 1,3-butanediol, 10.0 parts by mass of 3-methoxy-N, N-dimethylpropion Amid, 10.0 parts by mass 2-pyrrolidone, 1.0 part by mass 2-ethyl-1,3-hexanediol, 2.0 parts by mass of Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), and 22. 0 parts by mass of ion-exchanged water was mixed, stirred for 1 hour, and then filtered through a membrane filter having an average pore diameter of 1.2 μm to prepare the ink GJ-1 of Example 1.

(Examples 2 to 10, Comparative Examples 1 to 2)
-Making inks GJ-2 to 10 and RGJ-1 to 2-
In the preparation of the ink GJ-1 of Example 1, the inks of Examples 2 to 10 and Comparative Examples 1 and 2 were prepared in the same manner as in the preparation of the ink GJ-1 except that the composition was changed as shown in Table 3 below. GJ-2 to 10 and RGJ-1 to 2 were prepared. The numbers in each composition in Table 3 indicate parts by mass.

Next, the characteristics of the inks produced in Examples 1 to 10 and Comparative Examples 1 and 2 were evaluated according to the following methods and evaluation criteria. The results are shown in Table 4.

[Discharge recovery]
Inkjet printers (IPSiO GX5000 manufactured by Ricoh) are filled with the inks of Examples and Comparative Examples, left in an HL environment (32 ± 0.5 ° C., 15 ± 5% RH) for 3 hours, and then nozzles are used. A check pattern was printed and it was confirmed that there were no ejection defects such as missing dots or flying bends. Then, it was left as it was (decap state) for another 6 days and 12 days. After leaving, one sheet of high-quality paper My Paper (manufactured by Ricoh) with a solid printing part has a basis weight of 69.6 g / m2, a size of 23.2 seconds, and an air permeability of 21.0 seconds. It was printed and checked for missing dots and bending. When ink dots were missing or flight bending was observed in the nozzle check pattern, the printer nozzle was cleaned as a return operation to normal printing, and the total number of times was evaluated. From the total number of times obtained, the ejection recovery property of each ink was evaluated according to the following evaluation criteria. It was judged that it was practical when the evaluation was C or higher in both the case of leaving for 6 days and the case of leaving for 12 days.
〔Evaluation criteria〕
A: Cleaning 0 times B: Cleaning 1 time C: Cleaning 2 times D: Cleaning 3 times or more and less than 5 times E: Cleaning 5 times or more

400 Image forming device 401 Image forming device exterior 401c Device body cover 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For each color of black (K), cyan (C), magenta (M), yellow (Y) Main tank 411 Ink storage unit 413 Ink discharge port 414 Storage container case 420 Mechanical unit 434 Discharge head 436 Supply tube

Japanese Unexamined Patent Publication No. 2016-196621

Claims (13)

It has a structural unit represented by the following general formula (1), and further, at least one selected from the structural unit represented by the following general formula (2) and the structural unit represented by the following general formula (3). An ink containing a copolymer having substantially the same.

(In the structural unit represented by the general formula (1), R ₂ is a hydrogen atom or a methyl group, and L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms.)

(In the structural unit represented by the general formula (2), R ₃ is a hydrogen atom or a methyl group, and L ₂ contains an alkylene group having 2 or more and 12 or less carbon atoms or an ether group and has 4 or more carbon atoms. It is an alkylene group of 12 or less.)

(In the structural unit represented by the general formula (3), _R4 is a hydrogen atom or a methyl group.) The total mass of the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is 0.1% by mass or more and 10.0 mass with respect to the mass of the copolymer. The ink according to claim 1, which is less than or equal to%. The ink according to claim 1 or 2, wherein the copolymer has a weight average molecular weight of 5,000 or more and 40,000 or less. The ink according to any one of claims 1 to 3, wherein the copolymer has a structural unit having an anionic group. The ink according to claim 4, wherein the structural unit having an anionic group is a structural unit represented by the following general formula (4).

(In the structural unit represented by the general formula (4), R ₁ is a hydrogen atom or a methyl group, and X is a hydrogen atom or a cation.) The ink according to any one of claims 1 to 5, which contains water and a coloring material. The ink according to claim 6, wherein the coloring material is a pigment. The total mass of the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is when the mass of the structural unit represented by the general formula (1) is 1. The ink according to any one of claims 1 to 7, which is 0.0010 or more and 0.0500 or less. An ink container for containing the ink according to any one of claims 1 to 8. A recording device comprising the ink container according to claim 9 and a ejection means for ejecting the contained ink. A recording method comprising a ejection step of ejecting the ink according to any one of claims 1 to 8. It contains a monomer represented by the following general formula (5), and further, at least one selected from the monomer represented by the following general formula (6) and the monomer represented by the following general formula (7) is substantially contained. A method for producing an ink, which comprises a polymerization step of polymerizing a polymerizable material contained in.

(In the monomer represented by the general formula (5), R ₂ is a hydrogen atom or a methyl group, and L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms.)

(In the monomer represented by the general formula (6), R ₃ is a hydrogen atom or a methyl group, and L ₂ contains an alkylene group having 2 or more and 12 or less carbon atoms or an ether group and has 4 or more carbon atoms and 12 carbon atoms. The following alkylene groups.)

(In the monomer represented by the general formula (7), _R4 is a hydrogen atom or a methyl group.) A recording material having a recording medium and a printing layer formed on the recording medium and containing a copolymer.
The copolymer has a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3). A record having substantially at least one selected from.

(In the structural unit represented by the general formula (1), R ₂ is a hydrogen atom or a methyl group, and L ₁ is an alkylene group having 2 or more and 18 or less carbon atoms.)

(In the structural unit represented by the general formula (2), R ₃ is a hydrogen atom or a methyl group, and L ₂ contains an alkylene group having 2 or more and 12 or less carbon atoms or an ether group and has 4 or more carbon atoms. It is an alkylene group of 12 or less.)

(In the structural unit represented by the general formula (3), _R4 is a hydrogen atom or a methyl group.)

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