JP2011063735A - Ink composition and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition having excellent storage stability, adhesiveness to a substrate, ink dryability (blocking resistance and film strength) on the substrate and ejection stability, and an inkjet recording method. <P>SOLUTION: There are provided the ink composition containing a polar organic solvent and at least one kind of compound expressed by formula (1) or (2), and the inkjet recording method of using the ink composition. In the formulas, R<SP>1</SP>to R<SP>6</SP>are each independently 4-18C alkyl; and M<SP>1</SP>and M<SP>2</SP>are each independently Ca or Mg. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solvent-type ink composition and an ink jet recording method.

Conventionally, gravure printing for soft packaging materials, flexographic printing for sanitary, silk screen printing for metal plates, inkjet printing for indoor and outdoor advertising, etc. are generally known as printing methods for non-absorbent substrates. However, the ink composition used in these printing methods generally uses a solvent such as toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. corresponding to the second type organic solvent. There has been a demand for inks that are difficult to handle and have higher safety and hygiene due to the installation of a local exhaust system or the occurrence of regular medical checkup due to odors and the like. In particular, inkjet is different from gravure printing, flexo printing, and silk screen printing, which are printed at a dedicated large-scale factory, so it must be considered more safe, harmful, and odorous because it is used in small offices.
In order to improve safety, non-toluene inks that do not use toluene, which has a low environmental concentration setting value, and water-based inks based on alcohol have been developed for soft packaging gravure printing and sanitary flexographic printing.
The aqueous ink type ink composition for ink jet was also the center of development, but this type has the disadvantage that it cannot be printed on the surface of a substrate having a polymer surface such as polyvinyl chloride, and is not applicable to the second type organic solvent. Inks using certain nonpolar hydrocarbon solvents have been developed (Patent Documents 1 and 2).

Patent Document 1 discloses an electrostatic ink-jet ink composition containing a dispersion medium, charged particles containing at least a coloring material, and a charge control agent, wherein the charge control agent includes the following component (A) and ( An electrostatic ink-jet ink composition comprising a mixture containing B) and having a mass ratio of the following (B) component: (A) component of 10: 3 to 40: 3 is disclosed. Yes.
(A) (i) a chromium salt of C14-18 alkyl salicylic acid; (ii) calcium didecyl sulfosuccinate; and (iii) a copolymer of lauryl methacrylate, stearyl methacrylate and 2-methyl-5-vinylpyridine, the copolymer being 20 Each having a vinylpyridine content of ˜30% by weight and an average molecular weight of 15,000 to 250,000, wherein at least 50% of the basic nitrogen groups are salts of sulfosuccinic acid didecyl ester; A salt mixture composed of 10 parts by weight;
(B) a salt-free copolymer of (i) lauryl methacrylate and (ii) a monomer selected from the group consisting of 2- or 4-vinylpyridine, styrene and N, N-dimethylaminoethyl methacrylate, A copolymer having a molecular weight of 15,000 to 100,000 and a weight ratio of said monomer B (i) to B (ii) of 4: 1 to 50: 1.
In Patent Document 2, formed from a mixed solution of a reverse micelle solution and an aqueous dye solution in which a surfactant, for example, sodium di (2-ethylhexyl) sulfosuccinate, phosphatidylcholine, or a mixture thereof is dissolved in a nonpolar organic solvent. An oil-based ink for ink jet is disclosed.

JP 2006-233000 A JP 2002-212466 A

The ink composition described in Patent Document 1 is inferior in storage stability and inferior in adhesion to a plastic base because it uses a nonpolar organic solvent. In addition, since an organic solvent having a relatively low boiling point is used as the dispersion medium, ink drying on the substrate is fast, but there are drawbacks such as the solvent drying out when ink ejection is stopped and the head nozzles being easily clogged. .
In addition, the ink composition described in Patent Document 2 has excellent storage stability, but has a drawback of poor adhesion to a plastic base because a nonpolar solvent is used. In addition, there is a drawback that the drying of the solvent is fast and the head nozzle is likely to be clogged when ink ejection is stopped.
Therefore, recently, it is also not applicable to the second type organic solvent, and nitrogen-containing heterocyclic compounds such as 2-pyrrolidone and N-methyl-2-pyrrolidone, which are polar high boiling point solvents, or lactone compounds are also used as a co-solvent. Thus, solvent-based ink compositions have been developed aiming at solving the above problems.
However, these ink compositions use a solvent having a relatively slow drying property, and there is an insufficient point to achieve both the quick drying property of the ink on the substrate and the prevention of ink drying on the head. .
As described above, there has been a demand for the realization of an ink composition that sufficiently satisfies the problems such as ink storage stability, adhesion to a plastic substrate, ink drying on the substrate, and ejection stability.

  The object of the present invention, that is, the problem to be solved by the present invention is storage stability, adhesion to a substrate, ink drying on the substrate (blocking resistance, film strength), and ejection stability. It is to provide an ink composition excellent in properties and an ink jet recording method.

The above object has been achieved by the means described in <1> or <10> below. It is shown below with <2>-<9> which are preferable embodiments.
<1> an ink composition comprising a polar organic solvent and at least one compound represented by the following formula (1) or formula (2):

（式（１）及び式（２）中、Ｒ¹〜Ｒ⁶はそれぞれ独立に、炭素原子数４〜１８のアルキル基を表し、Ｍ¹及びＭ²はそれぞれ独立に、Ｃａ又はＭｇを表す。）

(In formula (1) and formula (2), R ^{1 to} R ⁶ each independently represents an alkyl group having 4 to 18 carbon atoms, and M ¹ and M ² each independently represent Ca or Mg. )

<2> The total content of the compounds represented by the formulas (1) and (2) is 0.1 to 10% by weight with respect to the total weight of the ink composition, according to the above <1>. An ink composition,
<3> The ink composition according to <1> or <2>, wherein the polar organic solvent includes a compound represented by the following formula (3):

（式（３）中、Ｒ⁷及びＲ⁸はそれぞれ独立に、−ＮＲ¹⁰−又は酸素原子を表し、Ｒ⁹は−Ｃ_mＨ_n−で表される炭化水素基を表し、分岐を有していてもよく、ｍは２〜８の整数を表し、ｎは（２ｍ−４）、（２ｍ−２）又は２ｍのいずれかの整数を表し、Ｒ¹⁰は炭素数１〜３のアルキル基、炭素数１〜３のヒドロキシアルキル基又は水素原子を表す。）

(In Formula (3), R ⁷ and R ⁸ each independently represent —NR ¹⁰ — or an oxygen atom, R ⁹ represents a hydrocarbon group represented by —C _m H _n —, and has a branch. M represents an integer of 2 to 8, n represents an integer of (2m-4), (2m-2) or 2m, R ¹⁰ represents an alkyl group having 1 to 3 carbon atoms, Represents a C 1-3 hydroxyalkyl group or a hydrogen atom.)

<4> The ink composition according to any one of <1> to <3>, wherein the polar organic solvent contains a cyclic carbonate compound and / or a cyclic urea compound.
<5> The ink composition according to any one of <1> to <4>, wherein the polar organic solvent includes propylene carbonate and / or ethylene carbonate;
<6> The ink composition according to any one of <1> to <5>, wherein the total content of the polar organic solvent is 50 to 90% by weight with respect to the total weight of the ink composition.
<7> The ink composition according to any one of <1> to <6>, further including a colorant,
<8> The ink composition according to any one of <1> to <8>, wherein R ^{1 to} R ⁶ are each independently an alkyl group having 8 to 12 carbon atoms.
<9> The ink composition according to any one of <1> to <8> above, which contains only the polar organic solvent as a solvent.
<10> A step of discharging the ink composition according to any one of the above <1> to <9> on a recording medium, and applying heat to the discharged ink composition, the ink composition An ink jet recording method comprising: fixing the ink.

  According to the present invention, an ink composition excellent in storage stability, adhesion to a substrate, ink drying on the substrate (blocking resistance, film strength), and ejection stability, and inkjet A recording method could be provided.

  Hereinafter, the present invention will be described in detail.

(Ink composition)
The ink composition of the invention contains a polar organic solvent and at least one compound represented by the following formula (1) or formula (2).
The ink composition of the present invention can be suitably used as an ink composition for ink jet recording.

（式（１）及び式（２）中、Ｒ¹〜Ｒ⁶はそれぞれ独立に、炭素原子数４〜１８のアルキル基を表し、Ｍ¹及びＭ²はそれぞれ独立に、Ｃａ又はＭｇを表す。）

(In formula (1) and formula (2), R ^{1 to} R ⁶ each independently represents an alkyl group having 4 to 18 carbon atoms, and M ¹ and M ² each independently represent Ca or Mg. )

  Since the compound represented by formula (1) or formula (2) is highly oil-soluble, there is no precipitation from the ink composition, and hence the storage stability of the ink is improved, and the surface active ability is obtained. The droplets of the above ink composition are considered to spread wet, have a large surface area, and dry quickly. In the vicinity of the head nozzle subjected to the ink repellent treatment, the conventional ink composition dries immediately because there is only a very small amount of the ink composition, but the compound represented by formula (1) or formula (2) It is presumed that the ink composition of the present invention containing the above can wet and spread to prevent drying.

(A) Polar organic solvent The ink composition of the present invention contains a polar organic solvent.
Examples of the polar organic solvent in the present invention include carbonic acid ester compounds, urea compounds, urethane compounds, glycol ether compounds, ester compounds, amide compounds, amine compounds, aldehyde compounds, ketone compounds, alcohol compounds, sulfone compounds, sulfoxide compounds, and nitriles. Compounds.
Among these, as the polar organic solvent, a carbonic acid ester compound, a urea compound, a urethane compound, a glycol ether compound, a cyclic ester compound, and a cyclic amide compound can be preferably exemplified, and a cyclic carbonate compound, a cyclic urea compound, a cyclic urethane compound, More preferred examples include glycol compounds, glycol ether compounds, cyclic ester compounds, and cyclic amide compounds, more preferred examples include cyclic carbonate compounds, cyclic urea compounds, and cyclic urethane compounds, and particularly preferred examples include cyclic carbonate compounds and cyclic urea compounds. it can.
The ink composition of the present invention may contain one type of polar organic solvent or two or more types in any proportion.
The ink composition of the present invention preferably contains only a polar organic solvent as a solvent.

  The ink composition of the present invention preferably contains a compound represented by the formula (3) as a polar organic solvent.

（式（３）中、Ｒ⁷及びＲ⁸はそれぞれ独立に、−ＮＲ¹⁰−又は酸素原子を表し、Ｒ⁹は−Ｃ_mＨ_n−で表される炭化水素基を表し、分岐を有していてもよく、ｍは２〜８の整数を表し、ｎは（２ｍ−４）、（２ｍ−２）又は２ｍのいずれかの整数を表し、Ｒ¹⁰は炭素数１〜３のアルキル基、炭素数１〜３のヒドロキシアルキル基又は水素原子を表す。）

(In Formula (3), R ⁷ and R ⁸ each independently represent —NR ¹⁰ — or an oxygen atom, R ⁹ represents a hydrocarbon group represented by —C _m H _n —, and has a branch. M represents an integer of 2 to 8, n represents an integer of (2m-4), (2m-2) or 2m, R ¹⁰ represents an alkyl group having 1 to 3 carbon atoms, Represents a C 1-3 hydroxyalkyl group or a hydrogen atom.)

At least one of R ⁷ and R ⁸ in formula (3) is preferably an oxygen atom, and both are oxygen atoms, that is, the organic solvent represented by formula (2) is a carbonate compound. Is more preferable.
R ¹⁰ in Formula (3) is preferably an alkyl group having 1 to 3 carbon atoms or a hydrogen atom.
In formula (3), m in R ⁹ is preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and further preferably 2 or 3.
In formula (3), n in R ⁹ is preferably (2m−2) or 2m, and more preferably 2m.
Specific examples of R ⁹ are preferably an ethylene group, a 1-methylethylene group, and a propylene group. Among these, an ethylene group or a 1-methylethylene group is particularly preferable.

  The ink composition of the present invention includes, as a polar organic solvent, a cyclic carbonate compound (for example, ethylene carbonate, propylene carbonate), a cyclic urea compound (for example, 1,3-dimethyl-2-imidazolidinone), and a cyclic compound. It preferably contains at least one compound selected from the group consisting of urethane compounds (for example, 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, 3-propyl-2-oxazolidinone, etc.), and cyclic It is more preferable to contain a carbonate compound and / or a cyclic urea compound, it is more preferable to contain a cyclic carbonate compound, and it is particularly preferable to contain ethylene carbonate and / or propylene carbonate.

  Preferred examples of the glycol ether compound that can be used as the polar organic solvent include polyoxyalkylene glycol monoalkyl ether or dialkyl ether, polyoxyethylene glycol monoalkyl ether or dialkyl ether, polyoxypropylene glycol monoalkyl ether. Or a dialkyl ether is more preferable, and a compound represented by the following formula (α), formula (β), or formula (γ) is more preferable.

As the dialkyl ether of polyoxyalkylene glycol, polyoxyethylene glycol dialkyl ether represented by the formula (α) is preferable.
R ²¹ — (OC ₂ H ₄ ) _n —OR ²² (α)
In the formula (α), R ²¹ and R ²² each independently represent an alkyl group having 1 to 3 carbon atoms, and R ²¹ and R ²² may be the same or different. n represents an integer of 2 to 4, and is preferably 2 or 3.
The alkyl group having 1 to 3 carbon atoms in R ²¹ and R ²² may be linear or branched, and examples thereof include a methyl group, an ethyl group, and a propyl group.

  Specific examples of the polyoxyethylene glycol dialkyl ether represented by the formula (α) include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, and diethylene glycol. Examples include ethyl methyl ether, triethylene glycol ethyl methyl ether, tetraethylene glycol ethyl methyl ether, diethylene glycol-di-n-propyl ether, and diethylene glycol-di-iso-propyl ether. Among these, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and diethylene glycol ethyl methyl ether are preferable, and diethylene glycol diethyl ether and triethylene glycol dimethyl ether are more preferable.

As the monoalkyl ether of polyoxyalkylene glycol, polyoxyethylene glycol monoalkyl ether represented by the formula (β) and polyoxypropylene glycol monoalkyl ether represented by the formula (γ) are preferably exemplified.
R ³¹ — (OC ₂ H ₄ ) _n —OH (β)
R ⁴¹ — (OC ₃ H ₆ ) _n —OH (γ)

In the formula (β), R ³¹ represents an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 3 to 6. Among the alkyl groups having 1 to 6 carbon atoms represented by R ³¹ , an alkyl group having 1 to 4 carbon atoms is preferable, and for example, a methyl group, an ethyl group, a propyl group, and a butyl group are preferable.
Specific examples of the polyoxyethylene glycol monoalkyl ether represented by the formula (β) include triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monobutyl ether, pentaethylene glycol monomethyl ether. And hexaethylene glycol monomethyl ether.

In the formula (γ), R ⁴¹ represents an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 2 to 3. Among the alkyl groups having 1 to 4 carbon atoms represented by R ⁴¹ , for example, a methyl group, an ethyl group, a propyl group, and a butyl group are preferable.
Specific examples of the polyoxypropylene glycol monoalkyl ether represented by the formula (γ) include polypropylene glycol monoalkyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, and dipropylene. Examples include glycol monobutyl ether and tripropylene glycol monomethyl ether.

In addition to the above, examples of the glycol ether compound include a monoalkyl ether monoalkyl ester compound of (poly) alkylene glycol.
Specifically, diethylene glycol monomethyl ether monomethyl ester, diethylene glycol monoethyl ether monomethyl ester, diethylene glycol monomethyl ether monoethyl ester, diethylene glycol monomethyl ether monobutyl ester, diethylene glycol monobutyl ether monomethyl ester, diethylene glycol monobutyl ether monoethyl ester, dipropylene glycol monomethyl ether Monomethyl ester, dipropylene glycol monoethyl ether monomethyl ester, dipropylene glycol monobutyl ether monomethyl ester, dipropylene glycol monoethyl ether monoethyl ester, dipropylene glycol monoethyl ether monobutyl ester, trie Ren glycol monomethyl ether monomethyl ester, triethylene glycol monoethyl ether monomethyl ester, triethylene glycol monobutyl ether monomethyl ester, tetraethylene glycol monomethyl ether monomethyl ester, tetraethylene glycol monoethyl ether monomethyl ester, tetraethylene glycol monobutyl ether monomethyl ester, etc. Illustrated.

  Preferred examples of the cyclic ester compound that can be used as the polar organic solvent include compounds represented by the following formula (δ).

R ⁵¹ in the formula (δ) represents a divalent hydrocarbon group, which may be linear, branched or cyclic, but may be a linear alkylene group It is preferable that
The number of carbon atoms of the divalent hydrocarbon group for R ⁵¹ is preferably 2 to 20, more preferably from 3 to 8, more preferably 3-5.
Among these, γ-butyrolactone is particularly preferable as the compound represented by the formula (δ).

  Preferred examples of the cyclic amide compound that can be used as the polar organic solvent include compounds represented by the following formula (ε).

R ⁶¹ in the formula (ε) represents a divalent hydrocarbon group, which may be linear, branched, or cyclic, but is a linear alkylene group It is preferable that
The number of carbon atoms of the divalent hydrocarbon group for R ⁶¹ is preferably 2 to 20, more preferably from 3 to 8, more preferably 3-5.
R ⁶² in formula (ε) represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and a methyl group. More preferably among these, as the compound represented by the formula (ε), N-methyl-2-pyrrolidone, 2-pyrrolidone and ε-caprolactam are preferable, and N-methyl-2-pyrrolidone is particularly preferable.

  The ink composition of the present invention does not contain a nonpolar organic solvent such as a hydrocarbon compound, a halogenated hydrocarbon compound, and an ether compound (excluding a glycol ether compound) and an inorganic solvent such as water. preferable. That is, the ink composition of the present invention preferably contains only a polar organic solvent as a solvent.

The total content of the solvent in the ink composition of the present invention is preferably 50% by weight or more, more preferably 50 to 95% by weight, and more preferably 50 to 90% by weight with respect to the total weight of the ink composition. More preferably, it is 70 to 90% by weight, most preferably 80 to 90% by weight.
Further, the total content of the polar organic solvent in the ink composition of the present invention is preferably 30% by weight or more, more preferably 50 to 95% by weight, based on the total weight of the ink composition. More preferably, it is -90 weight%, It is especially preferable that it is 70-90 weight%, It is most preferable that it is 80-90 weight%.

(B) Compound Represented by Formula (1) or Formula (2) The ink composition of the present invention is a compound represented by Formula (1) or Formula (2) (hereinafter also referred to as “specific compound”). Containing.

（式（１）及び式（２）中、Ｒ¹〜Ｒ⁶はそれぞれ独立に、炭素原子数４〜１８のアルキル基を表し、Ｍ¹及びＭ²はそれぞれ独立に、Ｃａ又はＭｇを表す。）

(In formula (1) and formula (2), R ^{1 to} R ⁶ each independently represents an alkyl group having 4 to 18 carbon atoms, and M ¹ and M ² each independently represent Ca or Mg. )

The alkyl group having 4 to 18 carbon atoms in R ^{1 to} R ⁶ may be linear, branched or have a ring structure.
In addition, the alkyl group having 4 to 18 carbon atoms in R ^{1 to} R ⁶ preferably has 8 to 12 carbon atoms.
R ¹ and R ² in the formula (1) can be independently bonded at any position of the benzene ring other than the position where the sulfur atom is bonded.
Specific examples of the alkyl group having 4 to 18 carbon atoms in R ^{1 to} R ⁶ include butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, 2-methyldodecyl, tridecyl, 2-methyltridecyl, tetradecyl, hexadecyl, octadecyl, and A cis-9-octadecenyl group is mentioned preferably, t-butyl group, 2-ethylhexyl group, dodecyl group and octadecyl group are mentioned more preferably, and a 2-ethylhexyl group and dodecyl group are particularly preferred.
More preferably, M ¹ and M ² in the formula (1) or the formula (2) are Mg.
The bond between M ¹ and —SO ₃ oxygen atom in formula (1) and the bond between M ² and —SO ₃ oxygen atom in formula (2) are ionic bonds or covalent bonds. May be.
In addition, the ink composition of the present invention may contain one kind of the compound represented by the formula (1) or the formula (2) alone, or may contain two or more kinds, and the formula (1). ) And one or more compounds each represented by formula (2) may be contained.
The ink composition of the present invention preferably contains at least one compound represented by formula (2), and is represented by formula (2) as a compound represented by formula (1) or formula (2). It is more preferable that only the compound to be contained is contained.
Moreover, it is preferable that the compound represented by the said Formula (1) or Formula (2) is a compound represented by following formula (1 ') or Formula (2').

R ¹ to R ^4, M ¹ and M ² in the formula (1 ') or formula (2') has the same meaning as R ¹ to R ^4, M ¹ and M ² in the formula (1) or Formula (2) The preferable range is also the same.
Specific examples of the compound represented by formula (1) or formula (2) include (1) -1 to (1) -5 and (2) -1 to (2) -4 as shown below. Can be preferably exemplified.

Although there is no restriction | limiting in particular as a preparation method of the compound represented by Formula (1), The method of making it neutralize with a calcium compound or a magnesium compound after making alkylbenzene react with sulfur trioxide can be illustrated.
Moreover, the compound represented by Formula (1) can also use a commercial item.

Although there is no restriction | limiting in particular as a preparation method of the compound represented by Formula (2), The method of performing sulfonation after making a C4-C18 alkyl alcohol and maleic anhydride react is illustrated.
Examples of these alcohols include higher alcohols derived from natural animals and plants such as butyl alcohol, capryl alcohol, cetyl alcohol, lauryl alcohol, myristyl alcohol, stearyl alcohol, oleyl alcohol, etc., and a synthetic linear aliphatic first by the Ziegler method. Secondary alcohols obtained by liquid phase oxidation of side chain aliphatic primary alcohols such as secondary alcohol, 2-ethylhexanol, 2-methyldodecanol, 2-methyltridecanol, etc., usually obtained by oxo synthesis, n-paraffin. Grade alcohol etc. are mentioned, Especially C8-C12 alcohol is preferable.
Moreover, a commercial item can also be used for the compound represented by Formula (2).

  The total content of the compounds represented by formula (1) and formula (2) in the ink composition of the present invention is preferably 0.01 to 20% by weight based on the total weight of the ink composition. 0.05 to 12% by weight, more preferably 0.1 to 10% by weight, particularly preferably 0.2 to 5% by weight, and 0.5 to 2 parts by weight. Most preferred. It is excellent in adhesiveness, blocking resistance, and the intensity | strength of a film | membrane as it is the said range.

(C) Colorant The ink composition of the present invention preferably contains (C) a colorant.
There is no restriction | limiting in particular as a coloring agent which can be used for this invention, It can select and use arbitrarily from well-known coloring agents, such as a pigment, an oil-soluble dye, a water-soluble dye, and a disperse dye. Among these, the colorant is preferably a pigment and / or an oil-soluble dye, and more preferably a pigment, from the viewpoint of excellent weather resistance and rich color reproducibility.

<Pigment>
The pigment is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include known organic pigments and inorganic pigments. Resin particles dyed with dyes, commercially available pigment dispersions and surfaces Treated pigments (for example, pigments dispersed in water, liquid organic compounds or insoluble resins, and pigment surfaces treated with resins, pigment derivatives, etc.) are also included. Examples of the pigment include, for example, “The Pigment Dictionary” edited by Seijiro Ito (2000, published by Asakura Shoten), Isao Hashimoto “Organic Pigment Handbook” (2006, published by Color Office), Herbst, K.M. Hunger, “Industrial Organic Pigments” (published by Wiley-VHC in 1992), JP 2002-12607, JP 2002-188025, JP 2003-26978, and JP 2003-342503 Can be mentioned.

Examples of the organic pigment and the inorganic pigment include a yellow pigment, a red pigment, a magenta pigment, a blue pigment, a cyan pigment, a green pigment, an orange pigment, a purple pigment, a brown pigment, a black pigment, and a white pigment.
Examples of the yellow pigment include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 10, 65, 73, 74, 75, 97, 98, 111, 116, 130, 167, 205, monoazo pigments, 61, 62, 100, 168, 169, Monoazo lake pigments such as 183, 191, 206, 209, 212, 12, 13, 14, 16, 17, 55, 63, 77, 81, 83, 106, 124, 126, 127, 152, 155, 170, 172, Disazo pigments such as 174, 176, 214 and 219, anthraquinone pigments such as 24, 99, 108, 193 and 199, monoazopyrazolone pigments such as 60, condensed azo pigments such as 93, 95, 128 and 166, 109, 110, 139, 173, 185 and other isoindoline pigments, 120, 151, 154, 175, 180, 181, 194 and other benz Izoazolone pigments, azomethine metal complex pigments such as 117, 129, 150 and 153, quinophthalone pigments such as 138, and quinoxaline pigments such as 213 are preferred.

  Examples of the red or magenta pigment include C.I. I. Pigment Red 193 and other monoazo lake pigments, 38 and other disazo pigments, 2, 5, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 22, 23, 31, 32, 112, 114, Naphthol AS pigments such as 146, 147, 150, 170, 184, 187, 188, 210, 213, 238, 245, 253, 256, 258, 266, 268, 269, etc. β-naphthol pigments such as 3, 4, 6, etc. , 49, 53, 68 etc. β-naphthol lake pigments, 237, 239, 247 etc. naphthol AS lake pigments, 41 etc. pyrazolone pigments, 48, 52, 57, 58, 63, 64: 1, 200 etc. BONA Lake pigments, xanthene lake pigments such as 81: 1, 169, 172, thioindigo pigments such as 88, 181, 279, 123, 149, 1 8, 179, 190, 224 etc. perylene pigment, 144, 166, 214, 220, 221, 242, 262 etc. condensed azo pigment, 168, 177, 182, 226, 263 etc. anthraquinone pigment, 83 etc. anthraquinone lake Pigments, benzimidazolone pigments such as 171, 175, 176, 185, 208, quinacridone pigments such as 122, 202 (including mixtures with CI Pigment Violet 19), 207, 209, 254, 255, 264, Diketopyrrolopyrrole pigments such as 270 and 272 are preferred, and azomethine metal complex pigments such as 257 and 271 are preferred.

Examples of the blue or cyan pigment include C.I. I. Naphthol AS pigments such as CI Pigment Blue 25 and 26, phthalocyanine pigments such as 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17: 1, 75, and 79 Dye lake pigments such as 1:56, 61, 62, anthraquinone pigments such as 60, indigo pigments such as 63, and dioxazine pigments such as 80 are preferable.
Examples of the green pigment include C.I. I. Dye lake pigments such as CI Pigment Green 1 and 4, phthalocyanine pigments such as 7 and 36, and azomethine metal complex pigments such as 8 are preferable.
Examples of the orange pigment include C.I. I. Monoazo pigments such as CI Pigment Orange 1, β-naphthol pigments such as 2, 3, 5 and the like, naphthol AS pigments such as 4, 24, 38 and 74, pyrazolone pigments such as 13, 34, 36, 60, 62, 64 and 72 Benzimidazolone pigments such as 15 and 16, disazo pigments such as 15 and 16, β-naphthol lake pigments such as 17 and 46, naphthalene sulfonic acid lake pigments such as 19; perinone pigments such as 43, quinacridone pigments such as 48 and 49, 51 Anthraquinone pigments such as 61, isoindolinone pigments such as 61, isoindoline pigments such as 66, azomethine metal complex pigments such as 68, and diketopyrrolopyrrole pigments such as 71, 73 and 81 are preferred.

Examples of the brown pigment include C.I. I. BONA lake pigments such as CI Pigment Brown 5, condensed azo pigments such as 23, 41 and 42, and benzimidazolone pigments such as 25 and 32 are preferred.
Examples of the purple pigment include C.I. I. Pigment violet 1, 2, 3, 27 etc. dyed lake pigments, 13, 17, 25, 50 etc. naphthol AS pigments, 5: 1 etc. anthraquinone lake pigments, 19 etc. quinacridone pigments, 23, 37 etc. dioxazine pigments A perylene pigment such as No. 29, benzimidazolone pigment such as No. 32, and a thioindigo pigment such as No. 38 are preferred.
Examples of the black pigment include C.I. I. Indazine pigments such as CI pigment black 1, carbon black as 7, graphite as 10, magnetite as 11, anthraquinone pigment as 20 and perylene pigment as 31 and 32 are preferable.
Examples of the white pigment include C.I. I. Pigment White 4 Zinc oxide, 6 Titanium oxide, 7 Zinc sulfide, 12 Zirconium oxide (zirconium white), 18 Calcium carbonate, 19 Aluminum oxide / silicon oxide (Kaolin clay), 21 Or the barium sulfate which is 22, the aluminum hydroxide (alumina white) which is 23, the silicon oxide which is 27, and the calcium silicate which is 28 are preferable.
The inorganic particles used in the white pigment may be simple substances, or may be oxides such as silicon, aluminum, zirconium, and titanium, organometallic compounds, and composite particles with organic compounds.
Among these, the titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, a large hiding power and coloring power, and is excellent in durability against acids, alkalis and other environments. used. In addition to the titanium oxide, another white pigment (may be other than the above-described white pigment) may be used in combination.

  The average particle size of the pigment particles is preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.45 μm, and still more preferably 0.015 to 0.4 μm. It is preferable to set selection, dispersion conditions, and filtration conditions. When the average particle size is in the above range, clogging of the head nozzle is suppressed, and the storage stability and transparency of the ink composition are excellent.

<Oil-soluble dye>
The oil-soluble dye that can be used in the present invention will be described below.
The oil-soluble dye that can be used in the present invention means a dye that is substantially insoluble in water. Specifically, the solubility in water at 25 ° C. (the mass of the dye that can be dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Therefore, the oil-soluble dye means a so-called water-insoluble pigment or oil-soluble dye, and among these, an oil-soluble dye is preferable.

Of the oil-soluble dyes that can be used in the present invention, any yellow dye can be used.
For example, phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; for example, azomethine dyes having open-chain active methylene compounds as coupling components; Examples include methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes; and other dye species such as quinophthalone dyes, nitro / nitroso dyes, Examples include acridine dyes and acridinone dyes.

Of the oil-soluble dyes that can be used in the present invention, any magenta dye can be used.
For example, aryl or heteryl azo dyes having phenols, naphthols, anilines as coupling components; for example, azomethine dyes having pyrazolones, pyrazolotriazoles as coupling components; for example arylidene dyes, styryl dyes, merocyanine dyes, oxonol dyes Methine dyes such as: diphenylmethane dyes, triphenylmethane dyes, carbonium dyes such as xanthene dyes; quinone dyes such as naphthoquinone, anthraquinone and anthrapyridone; condensed polycyclic dyes such as dioxazine dyes, etc. Can be mentioned.

Among the oil-soluble dyes that can be used in the present invention, any cyan dye can be used.
For example, indoaniline dyes, indophenol dyes or azomethine dyes having pyrrolotriazoles as coupling components; polymethine dyes such as cyanine dyes, oxonol dyes, merocyanine dyes; carboniums such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes Examples include dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; indigo / thioindigo dyes, and the like.

  Each of the above dyes may exhibit yellow, magenta, and cyan colors only after a part of chromophore (chromogenic atomic group) is dissociated. In this case, the counter cation may be an alkali metal or ammonium. Such inorganic cations may be used, organic cations such as pyridinium and quaternary ammonium salts may be used, and polymer cations having such a structure may be used.

Although not limited to the following, specific examples of preferable oil-soluble dyes include C.I. I. Solvent Black 3, 7, 27, 29 and 34; C.I. I. Solvent Yellow 14, 16, 19, 29, 30, 56, 82, 93 and 162; C.I. I. Solvent Red 1, 3, 8, 18, 24, 27, 43, 49, 51, 72, 73, 109, 122, 132 and 218; I. Solvent Violet 3; C.I. I. Solvent Blue 2,11,25,35,38,67 and 70; I. Solvent Green 3 and 7; I. Solvent Orange 2 etc. are mentioned.
Particularly preferred among these are: Nubian Black PC-0850, Oil Black HBB, Oil Yellow 129, Oil Yellow 105, Oil Pink 312, Oil Red 5B, Oil Scallet 308, Vali Fast Blue chemistry 2606e B2 (Manufactured by Co., Ltd.), Aizen Spiron Blue GNH (manufactured by Hodogaya Chemical Co., Ltd.), Neopen Yellow 075, Neopen Magenta SE1378, Neopen Blue 808, Neopen Blue FF4012, and Neo42 Cy FF4012.

<Disperse dye>
In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. The disperse dye generally includes a water-soluble dye, but in the present invention, the disperse dye is preferably used as long as it is soluble in a water-immiscible organic solvent.
Preferable specific examples of the disperse dye include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99, 100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 , 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9 etc. are mentioned.

The colorant that can be used in the present invention may be used alone or in combination of two or more.
In the present invention, the content of the colorant can be appropriately selected depending on the physical properties of the colorant (specific gravity, coloring power, color, etc.), and how many colors of the ink composition are combined to produce a printed material. From the viewpoint of hiding power and coloring power, it is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, and more preferably 1 to 10% by weight with respect to the weight of the whole ink composition. % Is particularly preferred.

  In the present invention, the colorant may be blended directly with each component during preparation of the ink composition, but it is added in advance to a polar organic solvent that can be used in the present invention and dispersed to obtain a pigment dispersion ( Also referred to as “mill base”) and then blended.

In the ink composition of the present invention, it is preferable to use a pigment as a colorant. When used, it is preferable to contain a dispersant in order to disperse the pigment stably in the ink composition.
As the dispersant that can be used in the present invention, a polymer dispersant is preferable. The “polymer dispersing agent” in the present invention means a dispersing agent having a weight average molecular weight of 1,000 or more.
The main chain skeleton of the polymer dispersant is not particularly limited, and examples thereof include a polyurethane skeleton, a polyacryl skeleton, a polyester skeleton, a polyamide skeleton, a polyimide skeleton, a polyurea skeleton, and the like, in terms of storage stability of the ink composition. A polyurethane skeleton, a polyacryl skeleton, and a polyester skeleton are preferable. The structure of the polymer dispersant is not particularly limited, and examples thereof include a random structure, a block structure, a comb structure, and a star structure. Similarly, in terms of storage stability, a block structure or a comb structure is used. preferable.

  As the polymer dispersant, the wet dispersant DISPERBYK series 101, 102, 103, 106, 108, 109, 110, 111, 112, 116, 130, 140, 142, 145, 161, commercially available from Big Chemie, 162, 163, 164, 166, 167, 168, 170, 171, 174, 180, 182, 183, 184, 185, 2000, 2001, 2020, 2050, 2070, 2096, 2150, commercially available from Ciba Specialty Chemicals EFKA Series 4008, 4009, 4010, 4015, 4020, 4046, 4047, 4050, 4055, 4060, 4080, 4300, 4330, 4340, 4400, 4401, 4402, 4403, 4406, 4800, 5400 10, 5044, 5054, 5055, 5063, 5064, 5065, 5066, 5070, 5244, SOLSPERSE series 3000, 11200, 13240, 13650, 13940, 16000, 17000, 18000, 20000, 21000, commercially available from Lubrizol. , 24000SC, 24000GR, 26000, 28000, 31845, 32000, 32500, 32550, 32600, 33000, 34750, 35100, 35200, 36000, 36600, 37500, 38500, 39000, 53095, 54000, 55000, 56000, 71000 DISPARLON series 1210, 1220, 1831, 1850, 18 available from 0, 2100, 2150, 2200, 7004, KS-260, KS-273N, KS-860, KS-873N, PW-36, DN-900, DA-234, DA-325, DA-375, DA-550, DA-1200, DA-1401, DA-7301, Ajisper series PB-711, PB-821, PB-822, PN-411, PA-111, commercially available from Ajinomoto Co., Inc., commercially available from Air Products Surfinol series 104A, 104C, 104E, 104H, 104S, 104BC, 104DPM, 104PA, 104PG-50, 420, 440, DF110D, DF110L, DF37, DF58, DF75, DF210, CT111, CT121, CT131, CT136 , GA, TG, TGE, Olfin series STG, E1004, commercially available from Nissin Chemical Industry Co., Ltd., SN Sparse series 70, 2120, 2190, Sanadepco Co., Ltd., Adeka Coal and Adekator, available from ADEKA Corporation Series, Sannonic series, Narrow Acty CL series, Emarmin series, New Pole PE series, Ionette M series, Ionette D series, Ionette S series, Ionette T series, Sanseparor 100 available from Sanyo Chemical Industries, Ltd. Can be mentioned.

  In addition to the above-mentioned commercially available products, the polymer dispersant includes a cationic monomer containing a basic group, an anionic monomer having an acidic group, a monomer having a hydrophobic group, and if necessary, a nonionic monomer and a hydrophilic group. What was synthesize | combined and copolymerized with other monomers, such as a monomer which has can be used. For details of other monomers such as a cationic monomer, an anionic monomer, a monomer having a hydrophobic group and a nonionic monomer or a monomer having a hydrophilic group, the monomers described in paragraphs 0034 to 0036 of JP-A-2004-250502 are used. Can be mentioned.

The polymer dispersant preferably contains a hydrophobic group in the molecule, and more preferably is insoluble in water. The polymer pigment dispersant containing a hydrophobic group can further improve the water resistance of the recorded matter. As an example of a preferable polymer pigment dispersant, a polyester dispersant having a polyester chain in the molecule can be given. By including a flexible polyester chain, the adsorptivity to the pigment is increased and the dispersibility is improved. Specifically, for example, a compound obtained by reacting a polyalkyleneimine and a polyester compound described in JP-A-54-37082, JP-A-61-174939, or the like, or described in JP-A-9-169821 A compound in which the side chain amino group of polyallylamine is modified with polyester, a graft polymer having a polyester type macromonomer described in JP-A-9-171253 as a copolymerization component, and described in JP-A-60-166318 Preferred examples include polyester polyol-added polyurethane.
As the polyester polymer dispersant, for example, “SOLSPERSE” (for example, SOLPERSE 17000, 24000GR, 28000, 32000, 38500) manufactured by Lubrizol, “DISPERBYK” (for example, DISPERBYK-161, 162, 167, manufactured by BYK Chemie) 168), “EFKA” manufactured by Ciba Specialty Chemicals (for example, EFKA 4047, 4050), “Ajisper” manufactured by Ajinomoto Co., Inc. (for example, Ajisper PB711, PN411, PA111, PB821, PB822), and the like. Both are on the market.

Among these polymer dispersants, the absolute value of the difference between the acid value and the amine value of the polymer dispersant is 0 mgKOH / g or more and 100 mgKOH / g or less in terms of the balance between storage stability and curing speed. Is more preferably 0 mgKOH / g or more and 60 mgKOH / g or less, and further preferably 0 mgKOH / g or more and 30 mgKOH / g or less.
The acid value represents an acid value per 1 g of the solid content of the polymer dispersant, and can be determined by potentiometric titration according to JIS K 0070.
The amine value represents an amine value per gram of the solid content of the polymer dispersant, and is a value converted to an equivalent of potassium hydroxide after being obtained by a potentiometric titration method using a 0.1N hydrochloric acid aqueous solution. When a plurality of dispersants are used, it can be expressed as the weight average.

  The preferred addition amount of the dispersant in the ink composition is such that the weight ratio (D / P) is P where the weight of the pigment in the ink composition is P and the weight of the polymer dispersant in the ink composition is D. 0.01 ≦ D / P ≦ 2.0 is preferable, 0.03 ≦ D / P ≦ 1.5 is more preferable, and 0.05 ≦ D / P ≦ 0.6 is satisfied. Is more preferable. Within the above range, pigment aggregation / sedimentation and ink viscosity increase do not occur, and an ink composition having excellent storage stability can be obtained, and an ink composition having low ink viscosity and excellent ejection stability can be obtained.

  Further, at the time of dispersion, in addition to the dispersing agent, a dispersing aid generally called synergist (for example, SOLPERSE series 5000, 12000, 22000, commercially available from Lubrizol, EFKA 6745, commercially available from Ciba Specialty Chemicals, Inc.) Etc.), various surfactants and antifoaming agents are also added to improve the dispersibility and wettability of the pigment.

In the present invention, when the pigment is dispersed, the pigment and the dispersant are mixed and then added and dispersed in the polar organic solvent, or the polar organic solvent and the dispersant are mixed and then the pigment is added. And dispersing. For the dispersion, for example, dispersion devices such as a ball mill, a bead mill, a sand mill, a salt mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used. Among these, a bead mill dispersing device is preferable because of its excellent dispersibility.
The beads used when performing bead mill dispersion are preferably those having an average diameter of 0.01 to 3.0 mm, more preferably 0.05 to 1.5 mm, and still more preferably 0.1 to 1.0 mm. Thus, a pigment dispersion having excellent stability can be obtained.

(D) Resin The ink composition of the present invention preferably contains at least one resin. By containing the resin, it is possible to further improve the scratch resistance of the image.
The resin also contains the polymer dispersant described above.
As the resin that can be used in the present invention, a (meth) acrylic resin is preferable, and a resin having 40 to 100 mol% of monomer units represented by the following formula (P) with respect to all monomer units is more preferable. In the resin, the monomer units represented by the following formula (P) may be used alone or in combination of two or more.

In formula (P), R ^a represents a hydrogen atom or a methyl group, X represents a single bond, COO or CONR ^b , R ^b represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and Y represents carbon The hydrocarbon group of number 1-20 is represented. The hydrocarbon group may contain an ether bond, an ester bond or an amide bond. Moreover, you may have a hydroxyl group, a carboxy group, and a halogen atom as a substituent.

  Preferred examples of the monomer for producing the resin include styrene, p-methoxystyrene, methyl (meth) acrylate, ethyl (meth) acrylate, allyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2- Ethihexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) Ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 2,2,2-tetrafluoroethyl (meth) acrylate, 1H, 1H, 2H, 2H-perfluorodecyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate , Glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (Meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-methacryloyloxytyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (Meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, (meth) acrylamide, N-butyl (meth) acrylamide, Np-hydroxyphenyl ( And meth) acrylamide and p-sulfamoylphenyl (meth) acrylamide. In addition, well-known monomers other than the above can be used as necessary.

  Moreover, as resin, anionic resin is preferable and anionic (meth) acrylic resin is more preferable. The anionic resin preferably has an acid value of 7 to 150 mgKOH / g, more preferably 20 to 100 mgKOH / g, and still more preferably 30 to 80 mgKOH / g. When the acid value is 7 mgKOH / g or more, the affinity with the pigment or the medium surface is good, and when it is 150 mgKOH / g or less, the effect of improving the scratch resistance is effective while suppressing the viscosity of the ink composition. Is obtained.

  The anionic resin preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 8,000 to 60,000, and still more preferably 10,000 to 30,000. When the weight average molecular weight is 5,000 or more, a steric repulsion effect is easily obtained when the anionic resin is adsorbed to the pigment particles in the ink composition, and the effect of improving the storage stability is enhanced. When the strength is improved and the viscosity is 100,000 or less, the ink viscosity can be suppressed and the fluidity of the ink can be maintained. In addition, a weight average molecular weight is calculated | required as a polystyrene conversion molecular weight by gel permeation chromatography.

Moreover, as an anionic resin, resin which has a polyether structure containing at least 1 of a polyoxyethylene structure or a polyoxypropylene structure is mentioned preferably.
As a resin having a polyether structure, a macromonomer having a polyether structure, an anionic monomer, and other monomers such as a cationic monomer, a nonionic monomer, a hydrophobic monomer, and a hydrophilic monomer as necessary may be used. Those synthesized by polymerization can be used. As the macromonomer having a polyether structure, a macromonomer in which methoxypolyethylene glycol or methoxypolypropylene glycol is bonded to an acryloyl group or methacryloyl group directly or via an alkyl group is preferably used. As the monomer, those similar to those exemplified as the monomer for synthesizing the polymer dispersant are preferably used. The anionic resin is preferably a (meth) acrylic resin obtained by copolymerizing these monomers.

  As the macromonomer having a polyether structure, commercially available products such as PE-200, PE-350, AE-200, AE-350, AP-400, AP-550, AP-800, manufactured by NOF CORPORATION. 70PEP-350B, 10PEP-550B, AEP, 50POEP-800B, 50AOEP-800B, PLE, ALE, PSE, ASE, PNE, ANE, PNP, ANP, PNEP-600, PME-200, PME-400, PME-1000, AME-400, PP-500, PP-800, PP-1000, AMP-10G, AMP-20G, AMP-60G, AM-90G, manufactured by Shin-Nakamura Chemical Co., Ltd., manufactured by Osaka Organic Chemical Industries, Ltd. Biscote # 355HP, Biscote # 310, Biscote # 310HP, Biscote # 31 HG, biscoat # 312, biscoat # 700, light acrylate EHDG-A, light acrylate EC-A, light acrylate MTG-A, light acrylate 130A, light acrylate P-200A, light acrylate NP-4EA manufactured by Kyoeisha Chemical Co., Ltd. , Light acrylate NP-8EA, light ester MC, light ester 130MA, light ester 041MA, Shin Nakamura Chemical Co., Ltd. NK ester M-20G, NK ester M-40G, NK ester M-90G, ADEKA Corporation Examples include Adekaria soap NE-10, Adekaria soap NE-20, and Adekaria soap NE-40.

The resin content in the ink composition of the present invention is preferably 1 to 25% by weight, more preferably 2 to 20% by weight, and more preferably 3 to 15% by weight with respect to the total weight of the ink composition. More preferably.
Further, when a pigment is used in the ink composition of the present invention, the resin content is preferably 10 to 200% by weight, more preferably 15 to 150% by weight, more preferably 20% to 20% by weight based on the total weight of the contained pigment. More preferred is ˜100% by weight. Within the above range, the ratio to the pigment is good and good fixability can be obtained, and the viscosity of the ink composition can be suppressed.
The ink solid content of the resin and colorant in the ink composition of the present invention is preferably 1 to 40% by weight, more preferably 5 to 30% by weight, and still more preferably 10 to 25% by weight.

(Other ingredients)
In addition to the above-described components, the ink composition of the present invention includes a surfactant, a surface conditioner, a leveling agent, an antifoaming agent, an antioxidant, a pH adjuster, a charge imparting agent, a bactericide, Known additives such as preservatives, deodorants, charge control agents, wetting agents, anti-skinning agents, fragrances, pigment derivatives and the like may be added as optional components.

<Method for Preparing Ink Composition>
There is no restriction | limiting in particular as a preparation method of the ink composition of this invention, The preparation method of a well-known solvent-type ink composition can be used. Specifically, each component is agitated by a simple dispersing machine such as a ball driving machine mill such as a ball mill, a centrifugal mill, a planetary ball mill, a high-speed rotating mill such as a sand mill, a medium stirring mill such as a stirring tank mill, a disper, The method of preparing by mixing and dispersing can be illustrated. About the addition order of each component, it is arbitrary. Preferably, a colorant, a polymer dispersant, and an organic solvent are premixed and then dispersed, and the resulting dispersion is mixed with the resin and the organic solvent. In this case, at the time of addition or after addition, the mixture is uniformly mixed with a simple stirrer such as a three-one motor, a magnetic stirrer, a disper, or a homogenizer. You may mix using mixers, such as a line mixer. Further, in order to make the dispersed particles finer, they may be mixed using a dispersing machine such as a bead mill or a high-pressure jet mill. Depending on the type of pigment or polymer dispersant, an anionic resin may be added during premixing before pigment dispersion.

The ink composition of the present invention preferably has a surface tension at 25 ° C. of 20 to 40 mN / m. The surface tension is measured using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) at 25 ° C. Further, the viscosity of the ink composition of the present invention is preferably 1 to 20 mPa · s, and more preferably 3 to 15 mPa · s. The viscosity is measured by using an ink composition at 25 ° C. using VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.).
It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature (25 ° C.) high, the ink composition can be prevented from penetrating into the recording medium even when a porous recording medium is used. Furthermore, it is preferable because bleeding of the ink composition at the time of landing of the ink composition droplet can be suppressed, and as a result, the image quality is improved.

When a pigment is used, the dispersion average particle diameter of the pigment particles in the ink composition is preferably ₅₀ to 150 nm, more preferably 60 to 100 nm in terms of volume average particle diameter D50. When D ₅₀ is 50 nm or more, it is appropriate from the viewpoint of light resistance of the recorded material, and when it is 150 nm or less, the discharge property is good and a fine recorded material with higher resolution can be obtained.
These can be easily adjusted by selecting the organic solvent and appropriately adjusting the type and amount of other components.

  Further, the surface tension at 25 ° C. of the ink composition of the present invention is preferably 20 to 35 mN / m, and more preferably 23 to 33 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and non-coated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and 35 mN / m or less is preferable in terms of wettability.

(Inkjet recording method and printed matter)
The ink jet recording method of the present invention includes a step of discharging the ink composition of the present invention and a step of fixing the ink composition by applying heat to the discharged ink composition. By performing these steps, an image of the ink composition fixed on the recording medium is formed.
Moreover, the printed matter of the present invention is a printed matter recorded using the ink composition of the present invention, and is preferably a printed matter recorded by the inkjet recording method of the present invention.

  There is no restriction | limiting in particular as an inkjet recording device used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known ink jet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the ink jet recording method of the present invention.

Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and a heating unit.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

In the ink composition of the present invention, it is desirable that the ejected ink composition has a constant temperature. Therefore, the ink jet recording apparatus preferably includes a means for stabilizing the ink composition temperature. The parts to be kept at a constant temperature are all the piping systems and members from the ink tank (intermediate tank if there is an intermediate tank) to the nozzle ejection surface. That is, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion.
The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors at each piping site and perform heating control according to the flow rate of the ink composition and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

  Using the above-described ink jet recording apparatus, the ink composition is ejected by heating the ink composition to preferably 25 to 80 ° C., more preferably 25 to 50 ° C., thereby increasing the viscosity of the ink composition, preferably 3 It is preferable to carry out after lowering to ˜15 mPa · s, more preferably 3 to 13 mPa · s. In particular, it is preferable to use an ink composition having a viscosity of 50 mPa · s or less at 25 ° C. as the ink composition of the present invention, since it can be discharged satisfactorily. By using this method, high ejection stability can be realized.

  Viscosity fluctuation of the ink composition has a great influence on the change of the droplet size and the change of the droplet discharge speed, and thus causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink composition during ejection as constant as possible. Therefore, in the present invention, the control range of the temperature of the ink composition is preferably ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and ± 1 ° C. of the set temperature. Further preferred.

Next, a process for fixing the ink composition by applying heat to the ejected ink composition will be described.
The ink composition discharged onto the recording medium is fixed on the surface of the recording medium by evaporating the solvent by a heating unit and softening the resin when the resin is contained.

  The heating means is not limited as long as the solvent can be dried, and a heat drum, hot air, an infrared lamp, a heat oven, a heat plate heating, or the like can be used.

In the ink jet recording method of the present invention, an ink set containing the ink composition of the present invention can be suitably used. For example, a cyan ink composition, a magenta ink composition, and a black composition may be combined with a yellow ink composition and used as an ink set.
In order to obtain a full-color image using the ink composition of the present invention, an ink set in which four dark ink compositions comprising yellow, cyan, magenta, and black are combined is preferable. More preferably, the ink set is a combination of a dark ink composition group of five colors consisting of yellow, cyan, magenta, black and white and a light cyan and light magenta ink composition group.
The “dark ink composition” in the present invention means an ink composition in which the content of the colorant exceeds 1.5% by weight of the entire ink composition.

  In order to obtain a color image by the ink jet recording method of the present invention, it is preferable to use an ink composition (ink set) of each color and superimpose in order from the color with the lowest brightness. Specifically, when using an ink set composed of yellow, cyan, magenta, and black ink compositions, it is preferably applied onto the recording medium in the order of yellow → cyan → magenta → black. Further, when an ink set including at least a total of seven colors of light cyan and light magenta ink composition groups and cyan, magenta, black, white, and yellow dark ink composition groups is used, In this case, it is preferable to apply the recording material in the order of white → light cyan → light magenta → yellow → cyan → magenta → black.

  In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. Examples of the recording medium include paper, plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, polyvinyl chloride, two Cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic laminated or vapor-deposited with the above metals A film etc. are mentioned. Among them, since the ink composition of the present invention is excellent in adhesion, it can be suitably used as a recording medium for a non-absorbent recording medium, and from the viewpoint of adhesion, vinyl chloride, polyethylene terephthalate, polyethylene, etc. A plastic substrate is preferable, a polyvinyl chloride substrate is more preferable, and a polyvinyl chloride sheet or film is still more preferable.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on weight.

  The pigment dispersions and ink composition materials used in the examples and comparative examples are shown below.

<Colorant>
・ IRGALITE BLUE GLVO (Cyan Pigment, CI Pigment Blue 15: 3, manufactured by Ciba Specialty Chemicals)
CINQUASIA MAGENTA RT355D (magenta pigment, CI Pigment Violet 19, manufactured by Ciba Specialty Chemicals)
NOVOPERM YELLOW 4G01 (yellow pigment, CI Pigment Yellow 155, manufactured by Clariant)
・ SPECIAL BLACK 250 (black pigment, carbon black, manufactured by Degussa)
・ KRONOS2300 (white pigment, titanium oxide, manufactured by KRONOS)

<Solvent>
Propylene carbonate (4-methyl-2-oxo-1,3-dioxolane, polar organic solvent, manufactured by Nippon Soda Co., Ltd.)
・ Ethylene carbonate (1,3-dioxolan-2-one, polar organic solvent, manufactured by Toagosei Co., Ltd.)
・ 1,3-Dimethyl-2-imidazolidinone (polar organic solvent, manufactured by Kawaken Fine Chemical Co., Ltd.)
・ Dipropylene glycol monomethyl ether (polar organic solvent, manufactured by Toho Chemical Industry Co., Ltd.)
・ Diethylene glycol diethyl ether (polar organic solvent, manufactured by Toho Chemical Industry Co., Ltd.)
・ Triethylene glycol dimethyl ether (polar organic solvent, manufactured by Toho Chemical Industry Co., Ltd.)
・ Γ-Butyrolactone (polar organic solvent, manufactured by BASF Japan Ltd.)
・ N-methyl-2-pyrrolidone (polar organic solvent, Sankyo Chemical Co., Ltd.)
・ Cyclohexane (nonpolar organic solvent, manufactured by BASF Japan Ltd.)
・ Dioxane (nonpolar organic solvent, manufactured by Tokyo Chemical Industry Co., Ltd.)

<Polymer dispersant>
・ Addisper PB821 (polyester polymer dispersant, manufactured by Ajinomoto Co., Inc.)
・ SOLSPERSE 32000 (polyester polymer dispersant, manufactured by Lubrizol)
・ SOLSPERSE 36000 (made by Lubrizol)

<Compound represented by formula (1) (specific compound)>
(1) -1 (Bis (t-butylbenzenesulfonic acid) calcium)
(1) -2 (bis (2-ethylhexylbenzenesulfonic acid) magnesium)
(1) -3 (bis (dodecylbenzenesulfonic acid) calcium, manufactured by Bayer AG)
(1) -4 (bis (dodecylbenzenesulfonic acid) magnesium, manufactured by Nanjing Chemlin Chemical Industry)
(1) -5 (bis (octadecylbenzenesulfonic acid) magnesium, manufactured by Nanjing Chemlin Chemical Industry)

<Compound represented by formula (2) (specific compound)>
(2) -1 (Bis [2-sulfobutanedioic acid 1,4-bis (2-ethylhexyl)] magnesium, Takemoto Yushi Co., Ltd.)
(2) -2 (bis (2-sulfobutanedioic acid 1,4-di-t-butyl) calcium)
(2) -3 (bis (2-sulfobutanedioic acid 1,4-didodecyl) magnesium)
(2) -4 (bis (2-sulfobutanedioic acid 1,4-dioctadecyl) magnesium)

<Compounds other than the compound represented by Formula (1) or Formula (2) (Comparative Compound)>
・ C-1 (sodium t-butylbenzenesulfonate)
・ C-2 (sodium octylbenzenesulfonate, manufactured by Tokyo Chemical Industry Co., Ltd.)
C-3 (sodium dodecylbenzenesulfonate, manufactured by Wako Pure Chemical Industries, Ltd.)
・ C-4 (sodium octadecylbenzenesulfonate)
C-5 (2-sulfobutanedioic acid 1,4-di-t-butyl sodium)
C-6 (2-sulfobutanedioic acid 1,4-bis (2-ethylhexyl) sodium, Takemoto Yushi Co., Ltd.)
C-7 (2-sulfobutanedioic acid 1,4-didodecyl sodium)
C-8 (2-sulfobutanedioic acid 1,4-dioctadecyl sodium)

  Among the compounds represented by the above formula (1) or formula (2) and the comparative compounds, compounds not described by the manufacturer were synthesized by applying a known method or a known method.

<Resin>
・ ELVACITE 2013 (methyl methacrylate / butyl methacrylate copolymer, manufactured by DuPont)

<Preparation of pigment dispersion>
A pigment dispersion was prepared with the formulation shown in Table 1 below. In addition, each numerical value of the compounding amount in Table 1 represents parts by weight.
Specifically, the mixture was stirred with a stirrer until uniform, and the obtained preliminary dispersion was further dispersed for 3 to 6 hours using 0.1 mm zirconia beads in a vertical bead mill (ready mill manufactured by IMEX Co., Ltd.). Pigment dispersions A to S were respectively prepared.

(Examples 1-32 and Comparative Examples 1-10)
<Preparation of ink composition>
Using the obtained pigment dispersions A to S, ink compositions of Examples 1 to 32 and Comparative Examples 1 to 10 having compositions shown in Tables 2 to 6 below were prepared. In addition, each numerical value of the compounding quantity in Tables 2-6 represents a weight part.
Next, a commercially available ink jet printer (SP-300V manufactured by Roland DG Inc.) was prepared as an ink jet recording apparatus.
Each of the obtained ink compositions was loaded into the ink jet printer, and an image was formed on a polyvinyl chloride sheet to obtain the following printed materials for evaluation.
The following evaluation was performed using each obtained ink composition and printed matter. The evaluation results are shown in Tables 2-6.

<Evaluation of storage stability of ink composition>
The obtained ink composition was sealed in a container, and after aging at 60 ° C. for 1 week, separation of the ink composition was observed. Evaluation was made according to the following criteria.
○: There was no change in the ink composition.
(Triangle | delta): Although the ink composition was isolate | separated slightly, it can be used without a problem by shaking lightly.
X: The ink composition was completely separated.

<Adhesion evaluation (cross hatch test)>
A crosshatch test (JIS K 5600-5-6) was performed as a method for evaluating adhesion to the substrate. In accordance with the inkjet image recording method, a solid image having an average film thickness of 12 μm was drawn.
Thereafter, a cross-hatch test was performed on each printed matter. In addition, evaluation was made into 6 steps evaluation of 0-5 according to JISK5600-5-6. Here, a rating of 0 means that the edges of the cut are completely smooth and there is no peeling on any grid eye.

<Ink drying properties>
As evaluation of ink drying property, the following blocking resistance and film strength evaluation were performed.

[Evaluation of blocking resistance (Evaluation of transfer amount to superposed substrate)]
After drawing a solid image having an average film thickness of 12 μm in accordance with the inkjet image recording method, an unprinted ester film E5000 is overlaid on the cured film so that the entire cured film of the printed material is covered. A load of 200 g / cm ² was applied, and the mixture was left in an atmosphere at 30 ° C. for 1 day. Moreover, blocking resistance was evaluated according to the following criteria.
4: There was no transfer to the upper film and no sticking.
3: Transfer to upper film was less than 1% of total film area.
2: Transfer to the upper film was 1% to 5% of the total film area.
1: Transfer to the upper film was 5% or more of the total film area.

[Film strength evaluation (pencil hardness test)]
As a method for evaluating the film strength, a pencil hardness test (JIS K 5600-5-4) was performed. In accordance with the inkjet image recording method, a solid image having an average film thickness of 12 μm was drawn.
HEIDON HHS2000 (manufactured by Shinto Kagaku Co., Ltd.) was used as the apparatus, and the weight was 750 g, the operation speed was 0.2 mm / sec, and an operation of 20 mm was performed.

<Discharge stability evaluation>
Using the ink jet printer, the head was discharged from the head for 30 minutes, and after stopping for 5 minutes, a solid image and an image (5 cm × 5 cm) obtained by recording a solid line on the recording medium were observed. The observed images were visually evaluated according to the following evaluation criteria.
A: The occurrence of missing dots due to the occurrence of white spots or the like was not recognized, and a good image was obtained.
B: The occurrence of missing dots due to the occurrence of white spots or the like was slightly observed, but it was of a level that would not hinder practical use.
C: Although dot missing occurred due to white spots or the like, the image was not unusable.
D: The image was unusable due to the occurrence of missing dots due to white spots.

Claims (10)

A polar organic solvent,
An ink composition comprising at least one compound represented by the following formula (1) or formula (2):

(In formula (1) and formula (2), R ^{1 to} R ⁶ each independently represents an alkyl group having 4 to 18 carbon atoms, and M ¹ and M ² each independently represent Ca or Mg. )   The ink composition according to claim 1, wherein the total content of the compounds represented by the formulas (1) and (2) is 0.1 to 10% by weight with respect to the total weight of the ink composition. The ink composition according to claim 1 or 2, wherein the polar organic solvent contains a compound represented by the following formula (3).

(In Formula (3), R ⁷ and R ⁸ each independently represent —NR ¹⁰ — or an oxygen atom, R ⁹ represents a hydrocarbon group represented by —C _m H _n —, and has a branch. M represents an integer of 2 to 8, n represents an integer of (2m-4), (2m-2) or 2m, R ¹⁰ represents an alkyl group having 1 to 3 carbon atoms, Represents a C 1-3 hydroxyalkyl group or a hydrogen atom.)   The ink composition according to claim 1, wherein the polar organic solvent contains a cyclic carbonate compound and / or a cyclic urea compound.   The ink composition according to claim 1, wherein the polar organic solvent contains propylene carbonate and / or ethylene carbonate.   The ink composition according to any one of claims 1 to 5, wherein the total content of the polar organic solvent is 50 to 90% by weight with respect to the total weight of the ink composition.   The ink composition according to claim 1, further comprising a colorant. The ink composition according to claim 1, wherein R ^{1 to} R ⁶ are each independently an alkyl group having 8 to 12 carbon atoms.   The ink composition according to any one of claims 1 to 8, comprising only the polar organic solvent as a solvent. A step of discharging the ink composition according to any one of claims 1 to 9 onto a recording medium; and
And a step of fixing the ink composition by applying heat to the ejected ink composition.