JP2011026497A - Nonaqueous ink for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide nonaqueous ink for inkjet recording, the ink excellent in ejection property and reducing a load on the electrode of an inkjet printer head. <P>SOLUTION: The nonaqueous ink for inkjet recording contains a colorant, a nonaqueous solvent and an alicyclic hydrocarbon expressed by formula (1): S-T having at least one substituent T. In formula (1), S represents an alicyclic hydrocarbon that allows conformation conversion; and T represents a monovalent chain type saturated hydrocarbon group that induces perturbation in the alicyclic hydrocarbon moiety. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-aqueous ink for inkjet recording.

  A piezo-type inkjet recording apparatus uses a piezo element (piezoelectric element) that deforms when a voltage is applied, and ejects ink from the nozzles by utilizing the pressure change in the ink chamber (pressure chamber) accompanying the deformation of the piezoelectric element. Is. As an ink jet printer head used (hereinafter, also simply referred to as “IJ head”), a piezoelectric member constitutes a part of an ink chamber (pressure chamber) in which ink is stored, and is formed on the surface of the piezoelectric member on the ink chamber side. There is a type in which an electrode is provided and a voltage is applied to the piezoelectric member from this electrode. In this type of IJ head, the electrode provided on the inner surface of the ink chamber and the ink are always in contact with each other.

  In the IJ head having a structure in which the electrode and the ink are in contact with each other, when an ink having conductivity such as a water-based ink is used, there is a problem that the ink is deteriorated due to a current flowing through the ink. Therefore, a technique is known in which a protective film having an insulating property is formed on the surface of the electrode to prevent current from flowing from the electrode to the ink even when conductive ink is used, thereby preventing deterioration of the ink. (Patent Document 1).

Japanese Patent No. 3943971

  According to the study of the present inventor, it has been found that in such type of IJ head, a pigment such as phthalocyanine copper contained in the ink used causes a chemical change, which may adversely affect the ink ejection performance. That is, the complex metal contained in the pigment is oxidized by oxygen dissolved in the ink, and the oxidized metal is reduced on the surface of the electrode to which a voltage is applied, and is deposited (deposited) on the electrode surface as a metal. Will deteriorate. For example, in the case of ink containing phthalocyanine copper, copper is deposited on the electrode surface.

  Furthermore, when an alcohol-based solvent is contained in the ink, a hydroxyl group is oxidized to a carboxy group with the reduction reaction of the metal oxide, and a carboxylate is formed. This carboxylate salt lowers the storage stability of the ink, and may be deposited near the nozzle to deteriorate the ink ejection property. As a result, the need for cleaning or replacement of the IJ head increases, and the printing operation is forced to be interrupted.

  Therefore, the present invention has been improved from the ink side by changing the viewpoint, and even if the ink and the electrode are in direct contact with each other in the ink chamber of the IJ head, the deterioration of the electrode is suppressed and good ejection is achieved. An object of the present invention is to provide an ink for inkjet recording capable of maintaining the properties.

According to one aspect of the present invention, an alicyclic hydrocarbon represented by the following formula (1) having a colorant, a non-aqueous solvent, and at least one substituent T:
ST formula (1)
(In the formula (1), S represents a conformationally convertible alicyclic hydrocarbon, and T represents a monovalent chain saturated hydrocarbon group that induces perturbation in the alicyclic hydrocarbon portion.)
And a non-aqueous ink for ink jet recording.

  The non-aqueous ink for ink jet recording according to the present invention includes a conformationally convertible alicyclic hydrocarbon substituted with a monovalent chain saturated hydrocarbon group that induces perturbation, and therefore the ink and the electrode are Even when used in an ink jet recording apparatus having an IJ head having a direct contact structure, the load on the electrode of the IJ head can be reduced. Therefore, in an ink jet recording apparatus including various types of IJ heads, the non-aqueous ink for ink jet recording according to the present invention can realize good ejection properties.

It is a fragmentary sectional view showing typically an example of an IJ head which can use ink concerning the present invention.

The non-aqueous ink for ink jet recording according to the present invention (hereinafter also simply referred to as “ink”) is a conformationally convertible alicyclic ring substituted with at least one chain saturated hydrocarbon group that induces perturbation. It is characterized by containing a formula hydrocarbon.
This alicyclic hydrocarbon is represented by the following formula (1).
ST formula (1)
In the formula (1), S represents a conformationally convertible alicyclic hydrocarbon, and T represents a monovalent chain saturated hydrocarbon group that induces perturbation.

  The S part, which is an alicyclic hydrocarbon, needs to be a compound having a conformation capable of conformational change. From the viewpoint of ease of conformational change, the S moiety is preferably a cycloalkane (alicyclic saturated hydrocarbon) having an unsaturated bond and having a ring structure having 4 to 8 carbon atoms. Here, the “cycloalkane containing a ring structure having 4 to 8 carbon atoms” refers to a spiro compound (described later) containing a ring having 4 to 8 carbon atoms in addition to a monocyclic cycloalkane having 4 to 8 carbon atoms. It is a concept that includes.

Preferable specific examples of the monocyclic cycloalkane include cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane.
Furthermore, from the viewpoint of heat of formation calculated by empirical molecular orbital calculation (COSMO method using MNDO for Hamiltonian, the same shall apply hereinafter) described later, the number of carbon atoms in the alicyclic hydrocarbon S part is most preferably 6. It is then preferably 5 or 7, and then preferably 4 or 8.
Usable alicyclic hydrocarbons include those having various structures in addition to the monocyclic compounds exemplified above as long as the conformational change is possible. For example, as a polycyclic structure in which two rings have one common atom, a monospiro bicyclic system (such as spiro [4.5] decane) or a polyspiro polycyclic system (spiro [4.2.4.2]). Tetradecane) alicyclic hydrocarbons may be used.

The substituent T in the alicyclic hydrocarbon is a monovalent chain saturated hydrocarbon group (alkyl group) that induces perturbation. Here, a substituent induces perturbation, which means that a steric hindrance is formed in the target molecule (ST in the above formula (1)) by the action of an electromagnetic field derived from the electrode, that is, the substituent is excluded. Inducing volume effect. In other words, the external force (electrophoretic force and / or dielectrophoretic force described later) received by the alicyclic hydrocarbon S part interferes with the external force called the electromagnetic field force of the electrode at the side chain (substituent T). When the ST compound molecule migrates with the electrophoretic force and / or the dielectrophoretic force generated due to the electromagnetic field, the substituent T interferes with its movement, and the conformational change effect is exerted on the S portion. It is to express.
The presence or absence of perturbation can be estimated from the values of heat of formation, dipole moment and surface area calculated by semiempirical molecular orbital calculation. That is, for the side chain T, the generated heat, the dipole moment and the surface area are calculated by the semi-empirical molecular orbital method. The calculated values are the generated heat is -25 kcal / mol or less and the dipole moment is 2 Debye or less. If the surface area is 50 ² or more, it can be determined that perturbation is induced in the present invention.

That is, the substituent T needs to be a substituent that induces steric hindrance enough to cause a conformational change of the alicyclic hydrocarbon ring that is the S portion, and therefore, an alkyl group having 4 to 8 carbon atoms. It is preferable that The substituent T may be either linear or branched, but is preferably branched in order to obtain higher perturbation.
Preferred examples of the substituent T include a t-butyl group, a 2-methylpentyl group, and a 2,2-dimethylbutyl group. Among them, a t-butyl group is preferable.
For reference, values of heat of formation, dipole moment, and surface area of each substituent are described below.

In the alicyclic hydrocarbon, a plurality of substituents T may be substituted, and at least one substituent T and other substituents are substituted unless the conformational change of the S part is prevented. You may do it. Examples of the substituent other than T include hydrocarbon groups such as methyl group, ethyl group, and n-propyl group, and halogeno groups such as fluoro group, bromo group, iodo group, and chloro group.
The number of substitutions on the alicyclic hydrocarbon ring is preferably 1 or 2 from the viewpoint of ease of conformational change. When there are a plurality of substituents, the positional relationship is not particularly limited. Taking a 36-membered ring as an example, the 1,2 (ortho) position, the 1,3 (meta) position, the 1,4 (para) position Either may be sufficient.

  Furthermore, according to the knowledge of the present inventors, in the alicyclic hydrocarbon of the above formula (1), in order to bring about the optimal conformational change and to make the effect of the present invention more excellent, the masses of S and T The ratio S: T is preferably in the range of 2: 1 to 1: 2.

When the alicyclic hydrocarbon of the above formula (1) has a monocyclic cycloalkane portion instead of a spiro ring system, the number of carbon atoms is 8 based on the value of heat of formation calculated by semiempirical molecular orbital calculation. It is preferably ~ 16. On the other hand, from the viewpoint of adjusting the viscosity of the ink, the carbon number of the alicyclic hydrocarbon is preferably 18 or less.
Further preferred alicyclic hydrocarbons are cycloalkanes having 8 to 16 carbon atoms substituted with at least one alkyl group having 4 to 8 carbon atoms.
An example thereof is a compound represented by the following formula.

In the above formulas (2-1) to (2-15), R ¹ is the substituent T (for example, a t-butyl group, a 2-methylpentyl group, or a 2,2-dimethylbutyl group), and R ² is a monovalent group selected from the substituent T, hydrocarbon group (methyl group, ethyl group, n-propyl group, etc.), or halogeno group (fluoro group, bromo group, iodo group, or chloro group). . R ¹ and R ² may be the same substituent or different substituents.

The ink may contain multiple types of alicyclic hydrocarbons.
When a plurality of alicyclic hydrocarbons are included, the total amount thereof is preferably 0.1% by mass or more in the ink. The upper limit of the blending is not particularly limited, but it is preferably blended in the ink in an amount of 5% by mass or less from the characteristics of the electrodes, specifically the calculated value of the electric flux density generated between the electrodes.

The reason why the effect of the present invention can be obtained by including the alicyclic hydrocarbon in the ink can be considered as follows although it is only an inference.
An electric field and a magnetic field are generated in the vicinity of the electrode of the IJ head, acting on a permanent dipole of a molecule that is a component contained in the ink, and causing a dielectric relaxation action and a dielectrophoresis action on various components of the ink. As a result, the ink component generates heat, or non-uniform dispersion occurs due to electrophoresis. Further, due to the dielectric polarization of the pigment, the pigment creates a periodic change in particle concentration along the lines of electric force. Aggregation occurs. As a result of the heat generation, electrophoresis, and / or dielectrophoresis of the ink component, it is considered that the ink becomes unstable, causing ejection abnormalities such as non-ejection of the head or bending of the flight. For example, the pigment may aggregate in the ink by electrophoresis and deposit on the head.
In general, when particles or molecules that are more polarizable than a medium are placed in an electric field, -q and + q charges appear on the upstream side and the downstream side of the lines of electric force due to dielectric polarization. Under an equal electric field, the resultant force acting on these charges is
-Q · E + q · E = 0
Thus, although it does not contribute to the movement of molecules, the above equation is not 0 under an unequal electric field such as an electrode of an IJ head, that is, particles and molecules move.

In addition, cyclic compounds such as cycloalkanes are restricted by the rotation of molecular bonds and have limited stable conformations. For example, taking cyclohexane as an example, in the cyclohexane ring, the “chair shape” is a stable conformation that hardly distorts the SP ³ hybrid orbital structure of carbon constituting the ring. When this “chair” conformation ring has a sterically large substituent, ie a perturbative substituent that causes steric hindrance in solution, the substituent is aquatorial (vertical) Is a little more stable than the conformation b present in the axial position (horizontal direction), so the conformation a and conformation b can easily undergo conformational change (ring conversion or conformational inversion). . By this conformational change, a molecule having a cyclohexane ring selectively undergoes electrophoresis and / or dielectrophoresis in an alternating electric field.

  Therefore, by controlling the conformational change of cycloalkane based on the molecular structure design of the substituent that induces perturbation, the behavior of electrophoresis and / or dielectrophoresis of the cycloalkane molecule can be predicted and controlled. Specifically, by providing a substituent that causes optimal conformational change in cycloalkane, it facilitates electrophoresis and / or dielectrophoresis, and is selected prior to other ink components (for example, pigments). In particular, it is considered that aggregation of other ink components and the like can be avoided by the electrophoresis and / or dielectrophoresis of cycloalkane.

  In the present invention, the alicyclic hydrocarbon S of the above formula (1) having an alicyclic hydrocarbon S moiety capable of conformational change and a saturated hydrocarbon group T which is a substituent for inducing perturbation is an alternating electric field. It is presumed that it exhibits good electrophoretic properties and dielectrophoretic properties, and pigment aggregation is suppressed by preferentially performing electrophoresis and / or dielectrophoresis prior to other ink components to cover the electrode surface. In addition, it can be considered that ink deposition stability on the electrode can be suppressed by suppressing the electrodeposition of the ink component on the electrode, but this theory is not restrictive. Dielectrophoresis here refers to the interaction between the electric field and the electric dipole moment induced thereby, the stronger the electric field (positive dielectrophoresis) or the weaker (negative dielectrophoresis) and the molecule. Is a phenomenon peculiar to high-frequency alternating current. Further, it is different in principle from the phenomenon of electrophoresis due to the generation of surface charge.

The ink contains a colorant and a non-aqueous solvent (hereinafter also simply referred to as “solvent”) as essential components.
As a coloring agent, a well-known pigment or dye can be used, and it is not specifically limited, You may use 2 or more types together.
Examples of the pigment include organic pigments such as azo, phthalocyanine, dye, condensed polycyclic, nitro, and nitroso (brilliant carmine 6B, lake red C, watching red, disazo yellow, hanza yellow, phthalocyanine blue, Phthalocyanine green, alkali blue, aniline black, etc.); metals such as cobalt, iron, chromium, copper, zinc, lead, titanium, vanadium, manganese, nickel, metal oxides and sulfides, and ocher, ultramarine, bitumen, etc. Carbon blacks such as inorganic pigments, furnace carbon black, lamp black, acetylene black and channel black can be used.

In the case of using a pigment, the average particle diameter of the pigment is preferably 300 nm or less, more preferably 150 nm or less, and further preferably 100 nm or less from the viewpoint of ejection stability and storage stability. Here, the average particle diameter of the pigment is a value measured by a dynamic light scattering particle size distribution analyzer LB-500 manufactured by Horiba, Ltd.
It is also preferable to use a so-called self-dispersing pigment that has been surface-treated in order to enhance dispersibility in a solvent.

  Examples of the dye include a basic dye, an acid dye, a direct dye, a soluble vat dye, an acid mordant dye, a mordant dye, a reactive dye, a vat dye, a sulfur dye, and the like. Water-soluble dyes can be used. Either or both of a pigment and a dye may be used as a colorant. However, the use of a pigment is preferable because an ink with less bleeding and show-through and excellent weather resistance can be obtained.

  The content of the colorant in the ink is usually 0.01 to 20% by mass, preferably 1 to 15% by mass from the viewpoint of printing density and ink viscosity, and more preferably 5 to 10% by mass. preferable.

The non-aqueous solvent is a non-polar organic solvent or a polar organic solvent having a 50% distillation point of 150 ° C. or higher. The 50% distillation point means a temperature at which 50% by mass of a solvent is volatilized, which is measured according to JIS K0066 “Testing method for distillation of chemical products”. From the viewpoint of safety, it is preferable to use one having a 50% distillation point of 160 ° C or higher, preferably 230 ° C or higher.
The ink according to the present invention is a non-aqueous ink that does not substantially contain water, and the non-aqueous ink herein means that the amount of water in the ink is 5% by mass or less.

For example, preferred examples of the nonpolar organic solvent include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents and the like. Examples of the aliphatic hydrocarbon solvent and alicyclic hydrocarbon solvent include, for example, “Teclean N-16, Teclean N-20, Teclean N-22, Nisseki Naphthezol L, Nissho Naphthezol M, manufactured by Nippon Petroleum Corporation. Nisseki Naphthezol H, No. 0 Solvent L, No. 0 Solvent M, No. 0 Solvent H, Nisseki Isosol 300, Nisseki Isosol 400, AF-4, AF-5, AF-6, AF-7 ", manufactured by Exxon “Isopar (Isopar) G, Isopar H, Isopar L, Isopar M, Exxsol D40, Exxsol D80, Exxsol D100, Exxsol D120, Exxsol D130, Exxsol D140, Norpar 13 or NorN13, Norpar 13 Can Kill. Preferred examples of the aromatic hydrocarbon solvent include “Nisseki Clean Sol G” (alkylbenzene) manufactured by Nippon Petroleum Corporation, “Solvesso 200” manufactured by Exxon, and the like.
These are solvents having a polar solubility parameter (also referred to as a Hansen solubility parameter) of 2 MPa ^1/2 or less.

As the polar organic solvent, ester solvents, alcohol solvents, higher fatty acid solvents, ether solvents, and mixed solvents thereof can be used. More specifically,
Methyl laurate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, isostearyl palmitate, methyl oleate, ethyl oleate, isopropyl oleate, butyl oleate, methyl linoleate, isobutyl linoleate, ethyl linoleate, isostearin Isopropyl acid, methyl soybean oil, soybean oil isobutyl, tall oil methyl, tall oil isobutyl, diisopropyl adipate, diisopropyl sebacate, diethyl sebacate, propylene glycol monocaprate, trimethylolpropane tri-2-ethylhexanoate, tri-2- Ester solvents having 14 or more carbon atoms in one molecule, such as glyceryl ethylhexanoate;
Alcohol solvents having 12 or more carbon atoms in one molecule, such as isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol, oleyl alcohol;
Higher fatty acid solvents such as isononanoic acid, isomyristic acid, hexadecanoic acid, isopalmitic acid, oleic acid, isostearic acid;
Preferable examples include ether solvents such as diethyl glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, and propylene glycol dibutyl ether.
These non-aqueous solvents can be used alone or in admixture of two or more.

Among these, the nonpolar organic solvent and the polar organic solvent are preferably used in combination. For example, for a nonpolar organic solvent having a polar solubility parameter of 2 MPa ^1/2 or less, the polar solubility parameter is 2 MPa ^{1/2 or} more. It is preferable to use a combination of polar organic solvents that are large and 7 MPa ^1/2 or less in an amount of 50 mass% or less of the total solvent. The polar organic solvents used in combination are preferably alcohols, glycols, polyglycols, glycols and esters of polyglycols, and mixtures thereof. Particularly preferred polar organic solvents are glycols, polyglycols and esters thereof, such as dipropylene glycol, polypropylene glycol with a molecular weight of 4000 or less, mono- and di-esters of ethylene glycol, di- and tri-ethylene glycol, ethoxylation Alkylphenol. In this case, the boiling point of the polar organic solvent is preferably 100 ° C. or higher, and more preferably 200 ° C. or higher.

  The non-aqueous solvent is adjusted to an amount that constitutes the remainder other than the essential component and the optional component and makes the total 100 with respect to the total amount of ink. As a guide, the non-aqueous solvent is preferably 50 to 95% by mass in the ink.

The ink can contain any component that is usually used in the art as long as the effects of the present invention are not impaired.
For example, when a pigment is blended as a colorant, it is preferable to use a pigment dispersant. The pigment dispersant is not particularly limited as long as the pigment is stably dispersed in the solvent, and examples thereof include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, High molecular weight polycarboxylic acid salt, long chain polyaminoamide and polar acid ester salt, high molecular weight unsaturated acid ester, high molecular weight copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic active agent, naphthalene sulfone Examples include acid formalin condensate salts, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonyl phenyl ether, polyester polyamines, stearylamine acetate and the like. These may be used alone or in combination of two or more.

The blending amount of the pigment dispersant when blending the pigment dispersant can be set as appropriate, but from the viewpoint of pigment dispersibility, it is about 0.05 to 1.0 part by weight with respect to 1 part of the pigment. Preferably, it is 0.1-0.7 part.
The pigment dispersant is preferably contained in an amount of about 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass with respect to the total amount of ink.

In addition, examples of various additives that can be contained in the ink include nozzle clogging inhibitors, antioxidants, conductivity modifiers, viscosity modifiers, surface tension modifiers, oxygen absorbers, and the like. These are not limited to specific compounds, and may be added as needed.
For example, as an antifoaming agent, a surface tension reducing agent, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or a polymer-based, silicone-based, or fluorine-based surfactant. It can be contained in the ink.

  In the case of an ink jet recording system, the viscosity of the ink varies depending on the nozzle diameter of the ejection head, the ejection environment, and the like, but in general, the viscosity is preferably 2 to 30 mPa · s at 23 ° C. 1 is more preferable. Here, the viscosity represents a value when the shear stress is increased from 0 Pa to 10 Pa over 1 minute at 23 ° C.

  The method for producing the ink is also not particularly limited. For example, in the case of a pigment ink, a pigment dispersion containing a pigment, a pigment dispersant, and a non-aqueous solvent is first prepared. It can be produced by adding ingredients. Or you may mix all the compounding components at once. As a dispersing means, a ball mill, a bead mill or the like can be preferably used.

The ink of the present invention can be applied to any ink jet recording apparatus. The ink jet printer may be of any system such as a piezo system, an electrostatic system, or a thermal system.
In particular, the ink of the present invention can be preferably used for an ink jet printer having an IJ head having a structure in which an electrode and an ink are in contact with each other. In this IJ head, for example, a part of an ink chamber (pressure chamber) in which ink is stored is composed of a piezoelectric member, an electrode is provided on the surface of the piezoelectric member on the ink chamber side, and voltage is applied from this electrode to the piezoelectric member. However, the present invention is not limited to this.

An example of this type of IJ head is schematically shown in FIG. FIG. 1 is a partial cross-sectional view of an IJ head including an ink chamber having at least a part of a wall surface made of a piezoelectric member (piezoelectric element) cut at the position of the piezoelectric member along the ink ejection direction. The IJ head 1 includes a plurality of ink chambers 2 to which ink is supplied and a nozzle plate 3 provided at the lower end surface of each ink chamber. The nozzle plate discharges ink corresponding to each ink chamber 2. Nozzle holes 31 are provided for this purpose. A part of the walls of each ink chamber 2 is composed of a piezoelectric member (piezoelectric element) 11. The upper end surface of the ink chamber 2 is closed by a lid member (not shown), and a nozzle supply pipe is provided on the lid member, and the ink chamber communicates with an external ink tank.
An electrode 5 is provided on the surface of the piezoelectric member 11 on the ink chamber 2 side and is in contact with the ink in the ink chamber 2. The piezoelectric member 11 is deformed by selectively applying a voltage to each electrode 5 to increase the pressure in the ink chamber, and a part of the ink is ejected from the nozzle hole 31 as an ink droplet 7.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. Hereinafter, “mass%” is simply referred to as “%”.
<Examples and Comparative Examples>
Each compounding component shown in the table was placed in a 250 ml polypropylene container and mixed, 450 g of zirconia beads (diameter 0.5 mm) was added, and the mixture was dispersed for 60 minutes by a rocking mill (Seiwa Giken Co., Ltd.). Thereafter, zirconia beads were separated by filtration, and the obtained contents were filtered through a 3.0 μm and 0.8 μm membrane filter to remove dust and coarse particles, thereby obtaining each ink.

The detail of each compounding component is as follows.
Pigment (1): Carbon black, “MA11” manufactured by Mitsui Chemicals, Inc.
Pigment (2): Phthalocyanine blue, Sanyo Dye Co., Ltd. “4044”
Pigment dispersant: “Solsperse 28000” manufactured by Nippon Lubrizol Corporation
Pigment dispersion aid: “Solsperse 5000” manufactured by Nippon Lubrizol Co., Ltd.
Unsaturated fatty acid ester solvent (1): Isopropyl palmitate, “Exepal IPP” manufactured by Kao Corporation
Unsaturated fatty acid ester solvent (2): Methyl oleate, “Exepar MOL” manufactured by Kao Corporation
Hydrocarbon solvent: “AF7” (naphthenic solvent) manufactured by Mitsubishi Oil Corporation
Saturated alcohol solvent: isostearyl alcohol

Alicyclic hydrocarbon (1): Compound in which R ¹ is a t-butyl group in the above formula (2-1) Alicyclic hydrocarbon (2): In the above formula (2-3), R ¹ is t-butyl. Compound which is group Alicyclic hydrocarbon (3): Compound in which R ¹ is a t-butyl group in the above formula (2-5) Alicyclic hydrocarbon (4): R ¹ in the above formula (2-6) Is a t-butyl group and R ² is a hexyl group. Alicyclic hydrocarbon (5): Compound in which R ¹ is a t-butyl group in the above formula (2-7) Alicyclic hydrocarbon ( 6): Compound in which R ¹ is a t-butyl group in the above formula (2-9) Alicyclic hydrocarbon (7): In the above formula (2-11), R ¹ is a t-butyl group, and R ² There compounds alicyclic hydrocarbon iodo group (8): wherein ^{R 1} is t- butyl group in the above formula (2-12), ² is a pentyl group compound

Comparative hydrocarbon (1): t-butylcyclopropane Comparative hydrocarbon (2): Compound in which R ¹ is an n-propyl group in the above formula (2-1) Comparative hydrocarbon (3): The above formula (2-3) compound comparison hydrocarbon ^{R 1} is a methyl group in) (4): the compound wherein ^{R 1} is a methyl group in formula (2-5) Comparative hydrocarbon (5): ^{R 1} in the above formula (2-7) Compound in which is an ethyl group Comparative hydrocarbon (6): a compound in which R ¹ is a methyl group in the above formula (2-9)

The following evaluation was performed using the obtained ink.
<Ink ejection performance>
An IJ head of ORPHIS HC5500 (manufactured by Riso Kagaku Kogyo Co., Ltd.) was attached to a continuous discharge jig (any IJ head can be attached and drive conditions etc. can be arbitrarily set). The IJ head of HC5500 has a structure (FIG. 1) in which the electrode and ink come into contact.

The discharge amount per dot was set to 42 pL, and ink was discharged from all 318 nozzles in total. This discharge was continuously performed for 5 minutes, and the number of non-discharge nozzles in 318 was evaluated according to the following criteria. The test was performed three times.
A: There were 0 or 1 non-ejection nozzle.
B: The number of non-ejection nozzles was 5 or less.
C: The number of non-ejection nozzles was 20 or less.
D: The number of non-ejection nozzles exceeded 20 but not all.
E: All nozzles (318 nozzles) did not discharge.

<Head electrode state>
The electrodes in the IJ head after the discharge test was performed three times were observed with the naked eye to confirm the presence or absence of deposits.
The above results are also shown in Table 1 and Table 2.

In the inks of the examples, the ink ejection performance was good, and no deposits were observed on the electrodes. Furthermore, pigment aggregation was not observed in the ink in the head.
On the other hand, the ink of Comparative Example 1 has a structure in which the alicyclic hydrocarbon used as the comparative hydrocarbon is a three-membered ring and cannot be conformationally changed. It was. In the inks of Comparative Examples 2 to 6, since the substituent of the used comparative hydrocarbon did not induce perturbation, the ink ejection performance was inferior, and deposits were observed on the electrodes. Furthermore, when an ink containing no alicyclic hydrocarbon was tested, the result was poor.

Claims (4)

A non-aqueous ink for ink-jet recording comprising a colorant, a non-aqueous solvent, and an alicyclic hydrocarbon represented by the following formula (1) having at least one substituent T.
ST formula (1)
(In the formula (1), S represents a conformationally convertible alicyclic hydrocarbon, and T represents a monovalent chain saturated hydrocarbon group that induces perturbation in the alicyclic hydrocarbon portion.)   The non-aqueous ink for inkjet recording according to claim 1, wherein the alicyclic hydrocarbon is a cycloalkane having a ring structure having 4 to 8 carbon atoms, which is substituted with an alkyl group having 4 to 8 carbon atoms.   The non-aqueous system for inkjet recording according to claim 1 or 2, wherein in the alicyclic hydrocarbon, the substituent T is selected from the group consisting of a t-butyl group, a 2-methylpentyl group, and a 2,2-dimethylbutyl group. ink.   The non-aqueous ink for inkjet recording according to any one of claims 1 to 3, wherein the alicyclic hydrocarbon has 8 to 18 carbon atoms.

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