JP6361496B2 - Ink solvent and ink - Google Patents

Description

  The present invention relates to an ink solvent and an ink, and more particularly, to an ink solvent containing a specific ionic liquid.

Conventionally, water-based ink whose main solvent component is water and oil-based ink whose main solvent component is an organic solvent are known as inks used in ink jet printers and the like.
Water or organic solvent used as the ink solvent may evaporate with time and cause a problem that the color material in the ink is solidified.
Particularly in the case of ink for ink jet, the nozzle diameter for ejecting ink is small, so if left in a state where the ink is filled in the head for a long time, the solvent evaporates from the nozzle tip and the solidified coloring material blocks the nozzle. As a result, non-ejection of ink, ink jetting direction failure, and the like occur, and as a result, printing failure occurs.

In addition, oil-based inks have the property that the charged electric charges are difficult to neutralize because the relative permittivity of the organic solvent is lower than that of water.
In particular, in the case of inkjet ink, the kinetic energy of ink droplets is small, and it is easily affected by external forces.
For this reason, the ink flying direction is bent due to the influence of the electrostatic force generated between the electric charge generated in the ink droplet and the electric charge held by the recording medium or the electric charge held on the recording medium. A defect such as a defect occurs, and as a result, a printing defect occurs.
In order to solve these problems, a technique for adding an ionic liquid to ink has been reported (see Patent Documents 1 and 2), but there is room for improvement in terms of image position accuracy and ejection properties after long-term storage. is there.

JP 2006-206686 A JP 2006-206687 A

  The present invention has been made in view of such circumstances, and an object thereof is to provide a novel and useful ink solvent containing an ionic liquid.

  As a result of intensive investigations to achieve the above object, the present inventors have found that an ionic liquid having a predetermined pyrrolidinium cation has a low viscosity and has good dispersibility and solubility of various coloring materials. The present invention was completed by finding it suitable as a solvent for ink.

（式中、Ｒ¹は、炭素数１〜３のアルキル基を表し、Ｒ²は、メチル基またはエチル基を表し、ｎは、１または２を表し、Ｘ^-は、１価のアニオンを表す。）
２． 前記Ｘ^-が、ＢＦ₄ ^-、ＰＦ₆ ^-、ＣＦ₃ＳＯ₃ ^-、ＣＦ₃ＣＯ₂ ^-、（ＣＦ₃ＳＯ₂）₂Ｎ^-または（ＦＳＯ₂）₂Ｎ^-を表す１のインク用溶媒、
３． 前記Ｒ¹が、メチル基またはエチル基を表す１または２のインク用溶媒、
４． 前記Ｒ¹およびＲ²が、共にメチル基を表す３のインク用溶媒、
５． １〜４のいずれかのインク用溶媒と、色材とを含むことを特徴とするインク、
６． 有機溶媒を含む５のインク、
７． 水を含む５のインク
を提供する。 That is, the present invention
1. An ink solvent comprising an ionic liquid represented by formula (1),

Wherein R ¹ represents an alkyl group having 1 to 3 carbon atoms, R ² represents a methyl group or an ethyl group, n represents 1 or 2, and X ⁻ represents a monovalent anion. .)
2. The ink solvent according to 1, wherein X ⁻ represents BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ or (FSO ₂ ) ₂ N ⁻ ;
3. 1 or 2 ink solvent wherein R ¹ represents a methyl group or an ethyl group,
4). A solvent for ink of 3, wherein R ¹ and R ² both represent a methyl group,
5. Ink characterized by including any one of the solvent for ink of 1-4 and a coloring material,
6). 5 inks containing organic solvent,
7). Five inks containing water are provided.

The ionic liquid used in the ink solvent of the present invention has a low viscosity and good dispersibility / dissolvability of various coloring materials, and is therefore suitable as a solvent for preparing various inks such as ink for inkjet printing. It is.
By using the ink solvent of the present invention, it is possible to reduce the amount of the organic solvent conventionally prepared using the organic solvent, which is advantageous in terms of environmental load.
In addition, the ink prepared using the ink solvent of the present invention provides printing with excellent image position accuracy, and the ink characteristics are stable even when stored for a long period of time. It is possible to achieve both, and more specifically, the obtained image and pattern are stabilized.

1 is a ¹ H-NMR spectrum diagram of MEMP • FSA obtained in Synthesis Example 1. FIG. 6 is a ¹ H-NMR spectrum diagram of MMMP · FSA obtained in Synthesis Example 3. FIG.

Hereinafter, the present invention will be described in more detail.
The solvent for ink according to the present invention comprises an ionic liquid represented by the formula (1).

R ¹ represents an alkyl group having 1 to 3 carbon atoms, and specific examples thereof may be linear, branched or cyclic, for example, methyl, ethyl, n-propyl, i-propyl, c-propyl group A linear alkyl group is preferable, and a methyl group and an ethyl group are more preferable, and a methyl group is still more preferable.
R ² represents a methyl group or an ethyl group, and is preferably a methyl group.
n represents 1 or 2.

  Among these, as the cationic structure, the following structure (A) is preferable from the viewpoint of more excellent thermal stability, and the following structure (B) is preferable from the viewpoint of lower viscosity.

X ⁻ is a monovalent anion and is not particularly limited as long as it is an anion capable of forming an ionic liquid, but in the present invention, BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ or (FSO ₂ ) ₂ N ⁻ is preferable, and in consideration of the solubility / dispersibility of the coloring material, low viscosity, etc., among others, BF ₄ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and (FSO ₂ ) ₂ N ⁻ are more preferable, and (CF ₃ SO ₂ ) ₂ N ⁻ and (FSO ₂ ) ₂ N ⁻ are provided because they give an ionic liquid suitable for an ink solvent with a low viscosity. Is preferred.
Any ionic liquid having any anion can be applied to both water-based inks and oil-based inks. However, when preparing a water-based ink, the anions include BF ₄ ⁻ , CF ₃ SO ₃ ⁻ and CF ₃ CO. ₂ ⁻ is preferable, and when an oil-based ink is prepared, the anions are particularly preferably BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , and (FSO ₂ ) ₂ N ⁻ .

  The ionic liquid used in the present invention can be produced by the method described in International Publication No. 2002/076924 or the specification of Chinese Patent Application No. 10147243, for example, N-alkoxyalkyl-N produced according to a conventional method. -An alkylpyrrolidinium halide (for example, chloride, bromide, etc.) and an alkali metal (for example, sodium, potassium, etc.) salt of a desired anion can be obtained by anion exchange reaction in water or an organic solvent. Moreover, after converting a halide salt into a hydroxide salt using an anion exchange resin, it can also be synthesized by other known methods such as synthesis by a neutralization reaction with an acid corresponding to an anion.

  Examples of the ionic liquid that can be suitably used in the present invention include, but are not limited to, the following.

The ink of the present invention includes at least the ink solvent composed of the ionic liquid described above and a coloring material.
In the present invention, the use of the ink solvent made of the ionic liquid is characterized in that the other materials including the coloring material constituting the ink are not particularly limited, and various known materials are used. Can be appropriately selected and used.

As coloring materials, dyes, pigments, pigments coated with resins (microcapsule pigments), colored fine particles in which resins colored with dyes or pigments are dispersed, etc. are appropriately used from those generally used as coloring materials for inks. Select and use.
As the dye, any of water-soluble dyes, disperse dyes, and oil-based dyes may be used.
Specific examples of water-soluble dyes include C.I. I. DirectBlack-2, 4, 9, 11, 17, 19, 22, 32, 80, 151, 154, 168, 171, 194, 195; I. DirectBlue-1, 2, 6, 8, 22, 34, 70, 71, 76, 78, 86, 112, 142, 165, 199, 200, 201, 202, 203, 207, 218, 236, 287, 307; C. I. DirectRed-1, 2, 4, 8, 9, 11, 13, 15, 20, 28, 31, 33, 37, 39, 51, 59, 62, 63, 73, 75, 80, 81, 83, 87, 90, 94, 95, 99, 101, 110, 189, 227; C.I. I. Direct Yellow-1, 2, 4, 8, 11, 12, 26, 27, 28, 33, 34, 41, 44, 48, 58, 86, 87, 88, 132, 135, 142, 144, 173; I. FoodBlack-1, 2; I. Acid Black-1, 2, 7, 16, 24, 26, 28, 31, 48, 52, 63, 107, 112, 118, 119, 121, 156, 172, 194, 208; I. Acid Blue-1, 7, 9, 15, 22, 23, 27, 29, 40, 43, 55, 59, 62, 78, 80, 81, 83, 90, 102, 104, 111, 185, 249, 254; C. I. Acid Red-1, 4, 8, 13, 14, 15, 18, 21, 26, 35, 37, 52, 110, 144, 180, 249, 257, 289; I. Acid Yellow-1, 3, 4, 7, 11, 12, 13, 14, 18, 19, 23, 25, 34, 38, 41, 42, 44, 53, 55, 61, 71, 76, 78, 79, 122 etc. are mentioned.

  Specific examples of disperse dyes include C.I. I. Disperse Yellow-3, 5, 7, 8, 42, 54, 64, 79, 82, 83, 93, 100, 119, 122, 126, 160, 184: 1, 186, 198, 204, 224; I. Disperse Orange-13, 29, 31: 1, 33, 49, 54, 66, 73, 119, 163; I. Disperse Red-1, 4, 11, 17, 19, 54, 60, 72, 73, 86, 92, 93, 126, 127, 135, 145, 154, 164, 167: 1, 177, 181, 207, 239, 240, 258, 278, 283, 311, 343, 348, 356, 362; I. DisperseViolet-33; I. Disperse Blue-14, 25, 26, 56, 60, 73, 87, 128, 143, 154, 165, 165: 1,176,183,185,201,214,224,257,287,354,365,368; C. I. DisperseGreen-6: 1,9 etc. are mentioned.

  Specific examples of oil-based dyes include C.I. I. Solvent Yellow-2, 6, 14, 15, 16, 19, 21, 33, 56, 61, 80; I. Solvent Orange-1, 2, 5, 6, 14, 37, 40, 44, 45; I. Solvent Red-1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; I. Solvent Blue-2, 11, 12, 25, 35, 36, 55, 73; I. SolventBlack-3, 5, 7, 22, 23; I. AcidBlack-123; C.I. I. SolventViolet-8, 3, 14, 21, 27; C.I. I. SolventGreen-3; C.I. I. Solvent Bow-3, 5, 20, 37 etc. are mentioned.

As the pigment, both organic pigments and inorganic pigments can be used, and the colors thereof are black; three primary colors of cyan, magenta, and yellow; specific colors such as red, green, blue, brown, and white; gold, silver, etc. The metallic luster color etc. are mentioned.
Examples of black pigments include carbon black pigments such as furnace black, lamp black, acetylene black, and channel black.
Specific examples of black pigments include Raven7000, Raven5750, Raven5250, Raven5000ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1200, Raven1190ULTRAII, Raven1170, Raven1170, Raven1250 MoguL, BlackPearlsL, Monarch700, Monarch800, Monarch880, Monarch900, Monarch1000, Monarch1100, Monarch1300, Monarch1400 (manufactured by Cabot Corporation); olorBlackFW1, ColorBlackFW2, ColorBlackFW2V, ColorBlack18, ColorBlackFW200, ColorBlackS150, ColorBlackS160, ColorBlackS170, Printex35, PrintexU, PrintexV, Printex140U, Printex140V, SpecialBlack6, SpecialBlack5, SpecialBlack4A, SpecialBlack4 (manufactured by Degussa); No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like.

Specific examples of cyan pigments include C.I. I. Pigment Blue-1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 22, 60, and the like.
Specific examples of the magenta pigment include C.I. I. PigmentRed-5,7,12,48,48: 1,57,112,122,123,146,168,184,202; I. PigmentViolet-19 etc. are mentioned.
Examples of yellow pigments include C.I. I. Pigment Yellow-1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 129, 138, 151, 154, 155, 180, etc. Is mentioned.

  Self-dispersed pigments obtained by subjecting the pigment to surface modification treatment, Cab-o-jet-200, Cab-o-jet-250, Cab-o-jet-260, Cab-o-jet-270 Commercially available self-dispersing pigments such as Cab-o-jet-300, IJX-444, IJX-55 (manufactured by Cabot), MicrojetBlackCW-1, CW-2 (manufactured by Orient Chemical Co., Ltd.), and the like can also be used.

  The amount of these color materials used is not particularly limited, but is usually about 0.1 to 50% by mass in the ink, preferably 1 to 30% by mass, and more preferably 1 to 20% by mass.

In the ink, in order to disperse the color material, a dispersant may be added at a mass ratio of 1 to 100% with respect to the color material.
Specific examples of the dispersing agent include styrene-maleic acid alkyl ester copolymer, styrene-methacrylic acid alkyl ester copolymer, styrene-acrylic acid alkyl ester copolymer, vinylnaphthalene-maleic acid alkyl ester copolymer, vinyl. Naphthalene-methacrylic acid alkyl ester copolymer, vinyl naphthalene-acrylic acid alkyl ester copolymer, acrylic acid alkyl ester-acrylic acid alkyl ester copolymer, methacrylic acid alkyl ester polymer, styrene-methacrylic acid phenyl ester-methacrylic acid Alkyl ester copolymer, styrene-methacrylic acid cyclohexyl ester-methacrylic acid alkyl ester copolymer, polystyrene, polyester, polyvinyl alcohol, styrene-styrene sulfone Copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl naphthalene-methacrylic acid copolymer, vinyl naphthalene-acrylic Acid copolymer, acrylic acid alkyl ester-acrylic acid copolymer, methacrylic acid alkyl ester-methacrylic acid, styrene-methacrylic acid alkyl ester-methacrylic acid copolymer, styrene-alkyl acrylate-acrylic acid copolymer, Styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer, and the like.

The addition amount of the ionic liquid is preferably 0.1% by mass or more and less than 50% by mass, more preferably 5 to 40% by mass, and still more preferably 10 to 30% by mass with respect to the whole ink. When the addition amount of the ionic liquid is less than 0.1% by mass, the image position accuracy and the jetability during long-term storage may be deteriorated, and when it exceeds 50% by mass, the drying time may be prolonged. is there.
The ink of the present invention contains water or an organic solvent together with the ionic liquid.

Examples of water include tap water, distilled water, ion-exchanged water, pure water, and ultrapure water. In terms of ink storage stability and prevention of clogging, ion-exchanged water, pure water, and ultrapure water are used. Is preferred.
Organic solvents include glycol solvents, amide solvents, amine solvents, alcohol solvents, sulfur-containing solvents, hydrocarbon solvents, ketone solvents, ester solvents, ether solvents, carbonate solvents, vegetable oils, and other organic solvents. A solvent is used.

  Specific examples of glycol solvents include glycols such as ethylene glycol, diethylene glycol, propylene glycol, propanediol, butylene glycol, triethylene glycol, 1,5-pentanediol, hexanediol, 1,2,6-hexanetriol, and glycerin. Of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diglycerin ethylene oxide adduct Examples include glycol ethers.

Specific examples of the amide solvent include 2-pyrrolidone, N-methyl-2-pyrrolidone, 1-cyclohexyl-2-pyrrolidone, triethanolamine and the like.
Specific examples of the alcohol solvent include methanol, ethanol, n-propanol, i-propanol, n-butanol, n-hexanol, benzyl alcohol, triethanolamine and the like.
Specific examples of the sulfur-containing solvent include thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like.

Specific examples of the hydrocarbon solvent include aliphatic hydrocarbons such as n-hexane, cyclohexane, n-heptane, methylhexane, n-octane, methylheptane, dimethylhexane, nonane, and decane; n-paraffin solvents, Paraffinic solvents such as iso-paraffinic solvents and cycloparaffinic solvents; aromatic hydrocarbons such as toluene, ethylbenzene and xylene.
Specific examples of the ketone solvent include acetone, methyl ethyl ketone, 2-pentanone, 2-hexanone, 2-heptanone, cyclohexanone and the like.
Specific examples of the ester solvent include methyl acetate, ethyl acetate, butyl acetate, vinyl acetate, ethyl propionate, and ethyl butyrate.
Specific examples of the ether solvent include diethyl ether, ethyl propyl ether, ethyl isopropyl ether and the like.

Specific examples of the carbonate solvent include ethylene carbonate and propylene carbonate.
Examples of vegetable oil include dry oil such as camellia oil, linseed oil, tung oil, poppy oil, walnut oil, safflower oil, and sunflower oil; semi-dry oil such as rapeseed oil; and non-drying oil such as coconut oil.
The above organic solvents may be used alone or in combination of two or more.

Furthermore, a surfactant can be added to the ink of the present invention at a ratio of about 0.01 to 5% by mass in the ink.
As the surfactant, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant may be used.
Specific examples of the nonionic surfactant include polypropylene glycol ethylene oxide adduct, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester. Sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, aliphatic alkanolamide, glycerin ester, sorbitan ester and the like.

Specific examples of the anionic surfactant include dialkyl sulfosuccinate, alkyl sulfate, dodecyl benzene sulfonate, keryl benzene sulfonate, isopropyl naphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutyl Biphenyl sulfonate, monobutyl biphenyl sulfonate, dibutylphenylphenol disulfonate, and the like can be given.
Specific examples of the amphoteric surfactant include alkylbetaine, sulfobetaine, sulfate betaine, imidazolidone betaine, amidopropyl betaine, aminodipropionate and the like.
Specific examples of the cationic surfactant include dihydroxyethyl stearylamine, 2-heptadecenyl-hydroxyethylimidazoline, lauryldimethylbenzylammonium chloride, cetylpyridinium chloride, stearamide methylpyridium chloride and the like.
These surfactants may be used alone or in combination of two or more.

  The viscosity of the ink of the present invention is not particularly limited, but when used as an inkjet ink, it is preferably 1 to 50 mPa · s, more preferably 1.2 to 40 mPa · s at 25 ° C., 1.5 -30 mPa · s is more preferable.

Hereinafter, although a synthesis example, an Example, and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.
The analyzers used in the examples are as follows.
[1] ¹ H-NMR spectrum apparatus: AL-400 manufactured by JEOL Ltd.
Solvent: Heavy dimethylformamide [2] Viscometer device: Programmable rheometer manufactured by BROOK FIELD

[1] Synthesis of ionic liquid [Synthesis Example 1] Synthesis of MEMP • FSA

Pyrrolidine (manufactured by Wako Pure Chemical Industries, Ltd.) 1.51 parts by mass and 2-methoxyethyl chloride (manufactured by Kanto Chemical Co., Ltd.) 1.00 parts by mass were mixed and reacted for 1 hour while refluxing. After the reaction, the reaction solution was separated into two layers, but the lower layer solidified when allowed to cool for a while. Only the upper layer was recovered by decantation, and purified by distillation under reduced pressure to obtain 0.96 parts by mass of the target product, N-2-methoxyethylpyrrolidine (boiling point 76 ° C./vapor pressure 45 mmHg) (yield 70%).
1.00 parts by mass of the obtained N-2-methoxyethylpyrrolidine and 2 times volume of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed and placed in an autoclave, and the system is purged with nitrogen did. After making it a closed system, about 1.00 parts by mass of methyl chloride gas (manufactured by Nippon Specialty Chemicals Co., Ltd.) was added with stirring at room temperature. When methyl chloride gas was introduced, the temperature and internal pressure increased. At the maximum, the temperature increased to about 53 ° C., and the internal pressure increased to 5.5 kgf / cm ² (about 5.4 × 10 ⁵ Pa). The reaction was continued without heating, and about 0.75 parts by mass of methyl chloride gas was added after 2 days. After further reaction for 1 day, the pressure was released, and the crystals formed in the system were filtered off under reduced pressure, dried using a vacuum pump, and N-2-methoxyethyl-N-methylpyrrolidinium chloride. 1.29 parts by mass were obtained (yield 92%).
To 1.00 parts by mass of the obtained N-2-methoxyethyl-N-methylpyrrolidinium chloride, an equivalent volume of ion-exchanged water was added and dissolved by stirring. This solution was added with stirring to a solution prepared by dissolving 1.29 parts by mass of potassium bis (fluorosulfonyl) amide (manufactured by Kanto Chemical Co., Inc.) in an equivalent volume of ion-exchanged water. After reacting at room temperature for 3 hours or more, the reaction solution separated into two layers is separated, and the lower organic layer is washed twice with ion-exchanged water and then dried using a vacuum pump. N-2-methoxyethyl-N-methylpyrrolidinium bis (fluorosulfonyl) amide (MEMP • FSA) 1.50 parts by mass was obtained (yield 83%). The ¹ H-NMR spectrum of MEMP • FSA is shown in FIG. The viscosity at 25 ° C. was 35 cP.

[Synthesis Example 2] Synthesis of MEMP • TFSA

  To 1.00 parts by mass of N-2-methoxyethyl-N-methylpyrrolidinium chloride obtained by the same synthesis method as described in Synthesis Example 1, this volume of ion-exchanged water was added and dissolved by stirring. This solution was added with stirring to a solution obtained by dissolving 1.68 parts by mass of lithium bis (trifluoromethanesulfonyl) amide (manufactured by Kanto Chemical Co., Inc.) in an equivalent volume of ion-exchanged water. After reacting at room temperature for 3 hours or more, the reaction solution separated into two layers is separated, and the lower organic layer is washed twice with ion-exchanged water and then dried using a vacuum pump. 1.50 parts by mass of N-2-methoxyethyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide (MEMMP · TFSA) was obtained (yield 83%). The viscosity at 25 ° C. was 50 cP.

Synthesis Example 3 Synthesis of MMMP • FSA

A solution prepared by dissolving 14.4 parts by mass of N-methylpyrrolidine (manufactured by Wako Pure Chemical Industries, Ltd.) in 200 parts by mass of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.) was ice-cooled, and chloromethyl methyl ether was stirred. 17.1 parts by mass (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After reacting overnight, the precipitated solid was filtered under reduced pressure using a Kiriyama funnel. The obtained white solid was dried using a vacuum pump to obtain 26.7 parts by mass of an intermediate N-methoxymethyl-N-methylpyrrolidinium chloride (yield 96%).
The obtained N-methoxymethyl-N-methylpyrrolidinium chloride 8.58 parts by mass was dissolved in 10 parts by mass of ion-exchanged water. This solution was added with stirring to a solution prepared by dissolving 12.5 parts by mass of potassium bis (fluorosulfonyl) amide (manufactured by Kanto Chemical Co., Ltd.) in 5 parts by mass of ion-exchanged water. After stirring overnight at room temperature, the reaction solution separated into two layers was separated, and the lower organic layer was washed four times with ion-exchanged water and then dried using a vacuum pump. 10.2 parts by mass of (methoxymethyl-N-methylpyrrolidinium bis (fluorosulfonyl) amide (MMMP · FSA)) was obtained (yield 63%). The ¹ H-NMR spectrum of MMMP · FSA is shown in FIG. The viscosity at 25 ° C. was 20 cP.

Synthesis Example 4 Synthesis of MMMP / TFSA

  Synthesis Example 2 except that N-2-methoxyethyl-N-methylpyrrolidinium chloride was replaced with N-2-methoxymethyl-N-methylpyrrolidinium chloride obtained by the same synthesis method as in Synthesis Example 3. In the same manner as described above, N-2-methoxymethyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide (MMMP · TFSA) was obtained as the target product. The viscosity at 25 ° C. was 42 cP.

[Synthesis Example 5] Synthesis of MEMP · CF3SO3

  A 5-fold volume of acetonitrile was added to 1.00 parts by mass of N-2-methoxyethyl-N-methylpyrrolidinium chloride obtained by the same method as in Synthesis Example 1, and dissolved by stirring. To this solution, 1.05 parts by mass of sodium trifluoromethanesulfonate (manufactured by Kanto Chemical Co., Inc.) was added and left overnight. After the precipitated crystals were filtered off, acetonitrile was distilled off with an evaporator and further evacuated with a vacuum pump for 1 hour. Chloroform was added in an amount 5 times the amount of the remaining substance and stirred to make it uniform, and then placed in a refrigerator (4 ° C.) and left overnight. The precipitated crystals were filtered out, chloroform was distilled off with an evaporator, and further dried using a vacuum pump. The target product, N-2-methoxyethyl-N-methylpyrrolidinium trifluoromethanesulfonate 1.55 mass Parts were obtained (95% yield). The viscosity at 25 ° C. was 88 cP.

Synthesis Example 6 Synthesis of MEMP • BF4

  It was synthesized by the method described in WO2002 / 0726924. The viscosity at 25 ° C. was 154 cP.

[2] Preparation of organic solvent-based ink After adding 500 g of ion-exchanged water to 100 g of the pigment and applying an ultrasonic homogenizer, the mixture was centrifuged with a centrifugal separator to remove the supernatant. After repeating this operation three times, the resulting pigment was dried under reduced pressure.
A mixture of a pigment and a pigment dispersant is kneaded using a roll mill so that the mass ratio of the pigment and the pigment dispersant is 1: 1, and then a predetermined amount of ionic liquid, organic solvent, and other additives are added. The mixture was added and dispersed in a bead mill for 2 hours to prepare a desired ink.
Using the above method, inks having the compositions shown in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 described below were prepared.

[Example 1-1]
C. I. PigmentRed-122: 5% by mass
Styrene-stearyl methacrylate copolymer: 5% by mass
MEMP / FSA: 10% by mass
POE (6) polyglyceryl ether (SC-E450, manufactured by Sakamoto Pharmaceutical Co., Ltd.): 20% by mass
Isopar M (made by ExxonMobil): 40% by mass

[Example 1-2]
Same composition as Example 1-1 except that MEMP • FSA was replaced with MEMP • TFSA

[Example 1-3]
Same composition as Example 1-1 except that MEMP • FSA was replaced with MMMP • FSA

[Example 1-4]
Same composition as Example 1-1 except that 30% by mass of MEMP / FSA and 40% by mass of Isopar M were used

[Example 1-5]
C. I. PigmentRed-122: 4% by mass
Styrene-stearyl methacrylate copolymer: 4% by mass
MMMP / TFSA: 6% by mass
Isopar H (made by ExxonMobil): 86% by mass

[Example 1-6]
Same composition as Example 1-5 except that MMMP • TFSA was replaced with MEMP • CF3SO3

[Example 1-7]
Same composition as Example 1-5 except that MMMP • TFSA was replaced with MEMP • BF4

[Example 1-8]
Same composition as Example 1-5 except for MMMP · TFSA 12 mass% and Isopar H 80 mass%

[Comparative Example 1-1]
C. I. PigmentRed-122: 5% by mass
Styrene-stearyl methacrylate copolymer: 5% by mass
Trimethylhexyl ammonium bis (trifluoromethanesulfonyl) imide: 30% by mass
SC-E450: 20% by mass
Isopar M: 40% by mass

[Comparative Example 1-2]
Same composition as Comparative Example 1-1 except that 10% by mass of trimethylhexylammonium bis (trifluoromethanesulfonyl) imide and 60% by mass of Isopar M were used.

[Comparative Example 1-3]
C. I. PigmentRed-122: 4% by mass
Styrene-stearyl methacrylate copolymer: 4% by mass
1-octadecyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide: 12% by mass
Isopar H: 80% by mass

[Comparative Example 1-4]
1-octadecyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide 6% by mass, isopar H 86% by mass, the same composition as Comparative Example 1-3

  Using the organic solvent-based inks prepared in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4, FX-C2 paper using a 600 dpi, 1024 nozzle prototype print head (14 ng drop amount) (Fuji Xerox Co., Ltd.) was printed, and the image position accuracy was measured according to the following method. The results are shown in Table 1.

(Image position accuracy measurement method)
An ink jet recording apparatus is filled with ink, and two drops of ink are printed on the same pixel. The image printed on the recording medium was analyzed, the center value of the ink was calculated, the distance between the ink centers was determined, and evaluated according to the following criteria.
A: The distance between the ink centers is less than 5 μm. O: The distance between the ink centers is 5 μm or more and less than 10 μm. Δ: The distance between the ink centers is 10 μm or more and less than 20 μm. X: The distance between the ink centers is 20 μm or more.

  As shown in Table 1, the inks prepared in Examples 1-1 to 1-8 had excellent image position accuracy regardless of the amount of ionic liquid, whereas the inks prepared in Comparative Examples had ion It can be seen that when the amount of liquid is small (Comparative Examples 1-2 and 1-3), the image position accuracy decreases.

[3] Preparation of water-based ink 500 g of ion-exchanged water was added to 100 g of pigment, and an ultrasonic homogenizer was applied. Centrifugation was performed with a centrifugal separator, and the supernatant was removed. After repeating this operation three times, the resulting pigment was dried under reduced pressure.
Ion exchange water and a pigment dispersant were added so that the pigment concentration in the initial pigment dispersion was 15% by mass, and the pH was adjusted to 7.5 using an aqueous sodium hydroxide solution. The pigment was dispersed in this pigment dispersion by applying an ultrasonic homogenizer. This dispersion was subjected to centrifugal separation (8000 rpm × 30 minutes) with a centrifugal separator, and the residue (20% by mass with respect to the total amount) was removed to obtain a pigment dispersion. A solvent, a pigment dispersion, and other additives were added and stirred so as to obtain a predetermined composition, and the obtained liquid was passed through a 5 μm filter to prepare a desired ink.
Using the above methods, inks having the compositions shown in Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-2 were prepared.

[Example 2-1]
MoguL (Cabot Corporation): 4% by mass
Styrene-acrylic acid-sodium acrylate copolymer: 1% by mass
MEMP / CF3SO3: 25% by mass
Acetylene glycol ethylene oxide adduct: 1% by mass
Ion exchange water: 69% by mass

[Example 2-2]
Same composition as Example 2-1 except that MEMP · CF3SO3 was replaced with MEMP · BF4

[Example 2-3]
Same composition as Example 2-1 except that 10% by mass of MEMP · CF 3 SO 3 and 84% by mass of ion-exchanged water were used.

[Comparative Example 2-1]
MoguL (Cabot Corporation): 4% by mass
Styrene-acrylic acid-sodium acrylate copolymer: 1% by mass
1-ethyl-3-methylimidazolium bromide: 25% by mass
Acetylene glycol ethylene oxide adduct: 1% by mass
Ion exchange water: 69% by mass

[Comparative Example 2-2]
The same composition as Comparative Example 2-1 except that 10% by mass of 1-ethyl-3-methylimidazolium bromide and 84% by mass of ion-exchanged water were used.

  About the water-based ink prepared in each of the above Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-2, using an inkjet recording apparatus (manufactured by Canon Inc.), the initial jetting performance and long-term performance are as follows. After storage, jetting properties were measured and evaluated. The results are shown in Table 2.

(Initial jetability measurement method)
An ink jet recording apparatus was filled with ink, a nozzle check pattern was printed, the number of ejection nozzles was observed, and the following criteria were evaluated.
◎: Discharge of all nozzles ○: Discharge of 90% or more of all nozzles Δ: Discharge of 80% or more and less than 90% of all nozzles ×: Discharge of less than 80% of all nozzles

(Measurement method of jetability after long-term storage)
The ink jet recording apparatus was filled with ink and left for 30 days in a general environment without a cap. After that, a nozzle check pattern was printed, the number of ejection nozzles was observed, and the following criteria were evaluated.
◎: Discharge of all nozzles ○: Discharge of 90% or more of all nozzles Δ: Discharge of 80% or more and less than 90% of all nozzles ×: Discharge of less than 80% of all nozzles

  As shown in Table 2, Examples 2-1 to 2-3 using the ink containing the coloring material and the ionic liquid are excellent in jetting property during long-term storage, but are insufficient in the comparative example. I understand that.

Claims (7)

An ink solvent comprising an ionic liquid represented by formula (1).

Wherein R ¹ represents an alkyl group having 1 to 3 carbon atoms, R ² represents a methyl group or an ethyl group, n represents 1 or 2, and X ⁻ represents a monovalent anion. .) The ink according to claim 1, wherein the X ⁻ represents BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ or (FSO ₂ ) ₂ N ^−. Solvent. The ink solvent according to claim 1, wherein R ¹ represents a methyl group or an ethyl group. The ink solvent according to claim 3, wherein R ¹ and R ² both represent a methyl group.   An ink comprising the ink solvent according to claim 1 and a coloring material.   The ink according to claim 5, comprising an organic solvent.   The ink according to claim 5, comprising water.

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