JP6970355B2 - Inkjet ink composition and inkjet recording method - Google Patents

Description

The present invention relates to an inkjet ink composition and an inkjet recording method.

An inkjet recording device for recording an image or a character by ejecting a minute droplet of ink from a nozzle hole of a recording head and adhering it to a recording medium is known. Further, as an ink used for such recording, for example, an ink jet ink containing various components such as a coloring material, a surfactant, water, and an organic solvent is known. Further, in ink jet ink compositions, solvent-based (non-aqueous) ink compositions that do not use water as a main solvent are being developed.

For example, Patent Document 1 discloses an ink composition containing a hydrocarbon solvent, a solvent having an ester group and an ether group, and a solvent that dissolves in both of them, and Patent Document 2 discloses an amide solvent (ether amides). ) Is disclosed, and Patent Document 3 discloses an ink composition containing three kinds of alcohols having different boiling points. Such a non-aqueous ink composition has good adaptability to a vinyl chloride-based recording medium, and is often used for recording for so-called sign applications such as outdoor signboards.

Japanese Unexamined Patent Publication No. 2012-012432. Japanese Unexamined Patent Publication No. 2012-046671 Japanese Unexamined Patent Publication No. 2010-018730

However, when the non-aqueous inkjet ink composition is used for signing applications, the weather resistance of the recorded material may be insufficient. That is, recorded materials for signatures are often used in an outdoor environment exposed to rain, sunlight, etc., and are required to have higher weather resistance than indoor use. According to the inventors, it is important to use inks containing orange pigments that have excellent weather resistance when trying to expand the color reproduction range of warm colors. It has become clear that it is important to use ink with a particularly wide color reproduction range of warm colors. It has also been found that good color development of ink is also important for fully exerting the function of expanding the color reproduction area.

As one of the means for improving the weather resistance of the inkjet ink composition, it is conceivable to use a coloring material having high weather resistance. However, in inkjet recording, many performances are required for each of a plurality of configurations such as an ink composition, a recording device, and a recording medium, and moreover, a high degree of balance between the configurations is required. Therefore, there is a concern that other performances of the inkjet ink composition will be insufficient simply by selecting a coloring material having high weather resistance. Further, when a cyclic ester compound or a specific amide compound is contained as a solvent in the non-aqueous ink composition in order to improve the scratch resistance of the recorded material, the color development property of the ink is inferior. was there.

The inventors use a combination of a specific pigment type and solvent to expand the warm color reproduction range and improve weather resistance, color development, and abrasion resistance while maintaining the overall performance of the inkjet ink composition. We found it important and came to make the present invention.

That is, one of the objects according to some aspects of the present invention is to provide an inkjet ink composition capable of forming an image having a wide warm color reproduction region and excellent weather resistance. Further, it is an object of the present invention to provide an inkjet ink composition having excellent scratch resistance and color development property. Another object of the present invention is to provide an ink set having excellent characteristics and an inkjet recording method.

The present invention has been made to solve at least a part of the above problems, and can be realized as the following aspects or application examples. Such an inkjet ink composition has an excellent warm color reproduction region and excellent weather resistance. Further, the recorded material is excellent in scratch resistance and color development.

[Application Example 1]
[1]
A solvent containing at least one of the solvent group A consisting of the cyclic ester compound and the compound represented by the following general formula (1), and C.I. I. A non-aqueous inkjet ink composition comprising Pigment Orange-43 (PO-43).

（式（１）中、Ｒ¹は炭素数１〜８のアルキル基を表し、Ｒ²およびＲ³はメチル基またはエチル基を表す。）

(In the formula (1), R ¹ represents an alkyl group having 1 to 8 carbon atoms, and R ² and R ³ represent a methyl group or an ethyl group.)

[2]
In [1], a non-aqueous inkjet ink composition further containing a fixing resin.

[3]
In [1] or [2]
A non-aqueous inkjet ink composition in which the ratio of the total content of the fixing resin to the total content of the solvent group A is 0.1 to 1.0.

[4]
A non-aqueous inkjet ink composition comprising at least one of the compounds represented by the following general formula (2) as a solvent in any one of [1] to [3].
R ¹ O- (R ² O) _m- R ³ ... (2)
[In the general formula (2), R ¹ and R ³ independently represent hydrogen or an alkyl group having 1 or more and 5 or less ^{carbon atoms, and R 2} represents an alkylene group having 2 or 3 carbon atoms. Represents an integer of 2-6. However, ^{at least one} of R 1 and R ³ is an alkyl group having 1 or more and 5 or less carbon atoms. ]

[5]
In [4]
A non-aqueous inkjet ink composition in which the total content of the compound represented by the general formula (2) is 10% by mass or more and 90% by mass or less with respect to the total amount of the inkjet ink composition.

[6]
In any one of [1] to [5],
A non-aqueous inkjet ink composition having a solvent A content of 2 to 40% by mass.

[7]
The non-aqueous inkjet ink composition according to any one of [1] to [6], which is used for recording on a vinyl chloride-based recording medium.

[8]
The non-aqueous inkjet ink composition according to any one of [1] to [7], wherein the fixing resin is at least one of a (meth) acrylic resin and a vinyl chloride resin.
[9]
The fixing resin contains 2.5 to 5% by mass of a (meth) acrylic resin with respect to the ink composition and 0.5 to 2.5% by mass of a vinyl chloride resin with respect to the ink composition [1]. The non-aqueous inkjet ink composition according to any one of [8].

[10]
A specific non-aqueous inkjet ink composition containing Pigment Orange-43 (PO-43) as a solvent and a pigment, a non-aqueous cyan ink composition containing a solvent and a pigment, and a non-aqueous magenta containing a solvent and a pigment. An ink set comprising at least an inkjet ink composition and a non-aqueous yellow inkjet ink composition containing a solvent and a pigment.

[11]
The specific non-aqueous inkjet ink composition, non-aqueous cyan inkjet ink composition, non-aqueous magenta inkjet ink composition, and non-aqueous yellow inkjet ink composition are each a compound represented by the following general formula (2) as a solvent. The ink set according to [10], which comprises one or more kinds.
R ¹ O- (R ² O) _m- R ³ ... (2)
[In the general formula (2), R ¹ and R ³ independently represent hydrogen or an alkyl group having 1 or more and 5 or less ^{carbon atoms, and R 2} represents an alkylene group having 2 or 3 carbon atoms. Represents an integer of 2-6. However, ^{at least one} of R 1 and R ³ is an alkyl group having 1 or more and 5 or less carbon atoms. ]

[12]
The ink set according to [10] or [11], wherein the specific non-aqueous inkjet ink composition is the non-aqueous inkjet ink composition according to any one of [1] to [9].

[13]
Inkjet recording is performed on a recording medium by an inkjet method using the inkjet ink composition according to any one of [1] to [9] or the ink set according to any one of [10] to [12]. Recording method.

Hereinafter, some embodiments of the present invention will be described. The embodiments described below describe an example of the present invention. The present invention is not limited to the following embodiments, and includes various modifications implemented without changing the gist of the present invention. Not all of the configurations described below are essential configurations of the present invention.

1. 1. Inkjet Ink Composition The inkjet ink composition according to the present embodiment contains a solvent and a pigment. The inkjet ink composition according to the present embodiment is a non-aqueous ink composition, and is preferably a solvent-based ink composition containing a volatile solvent (mainly an organic solvent) as a main component. It is preferable to obtain a non-photocurable ink for recording by fixing the solid content by drying the solvent by heating or room temperature after adhering it on a recording medium. A photocurable ink that is cured by irradiating with radiation (light) may be used, but a non-photocurable ink is preferable because it does not require irradiation.
The non-water-based ink composition does not contain water as a main solvent component, but is an ink composition that does not contain water as a functional component for exhibiting the function and performance of the ink. The content of water with respect to the ink composition is 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and more particularly. It is preferably 0.1% by mass or less, and may not contain water. The solvent content of the non-aqueous inkjet ink composition in the present embodiment is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 85. ~ 98% by mass.

1.1. Solvent The solvent contained in the inkjet ink composition according to the present embodiment preferably contains at least one of the solvent group A composed of a cyclic ester compound or a compound represented by the following general formula (1).

1.1.1. Cyclic ester compound The inkjet ink composition according to this embodiment preferably contains a cyclic ester (cyclic lactone) as a solvent. Since the inkjet ink composition contains a cyclic ester (cyclic ester compound), a part of the recording surface (preferably a recording surface containing a vinyl chloride resin) of the recording medium is dissolved and inkjet into the inside of the recording medium. The ink composition can be infiltrated. By permeating the ink composition into the recording medium in this way, the abrasion resistance (friction fastness) of the image recorded on the recording medium can be improved. In other words, since the cyclic ester has a high affinity with the vinyl chloride resin, it is easy for the components of the inkjet ink composition to infiltrate the recording surface (it is easy to bite). As a result of the cyclic ester having such an action, it is considered that the inkjet ink composition containing the cyclic ester can form an image having excellent scratch resistance even under severe conditions such as an outdoor environment. In addition, since it has excellent solubility of solid content components such as fixing resin contained in the ink composition, when the ink is ejected from the inkjet head by preventing the precipitation of the resin in the ink during long-term storage or use of the ink. It is preferable because it does not cause a defective ejection and the pigment adhering to the surface of the recorded material can be uniformly covered with the resin, and the weather resistance of the recorded material tends to be more excellent. On the other hand, the cyclic ester promotes the penetration of the ink into the recording medium and thus suppresses the spread of the ink in the lateral direction on the surface of the recording medium, which tends to hinder the color development of the ink composition in the recording material. There is.

The cyclic ester is a compound having a structure in which the hydroxyl group and the carboxyl group are dehydrated and condensed in one molecule having a hydroxyl group and a carboxyl group. The cyclic ester has a heterocycle containing two or more carbon atoms and one oxygen atom, and has a structure in which a carbonyl group is arranged adjacent to the oxygen atom forming the heterocycle, and is collectively referred to as a lactone. It is a compound.

Examples of the cyclic ester having a simple structure include β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. be able to. The number of ring members of the heterocycle of the cyclic ester is not particularly limited, and for example, any side chain may be bonded to the ring member of the heterocycle. The cyclic ester may be used alone or in combination of two or more.

From the viewpoint of further enhancing the scratch resistance of the image formed by the ink composition of the present embodiment, among the above-exemplified cyclic esters, a cyclic ester having a 3-membered ring or more and a 7-membered ring or less is preferable, and a 5-membered ring or a 6-membered ring is preferable. It is more preferable to use a cyclic ester of a member ring, and in any case, it is more preferable to have no side chain. Specific examples of such cyclic esters include β-butyrolactone, γ-butyrolactone, and γ-valerolactone. Further, since such a cyclic ester has a high affinity with polyvinyl chloride in particular, the effect of enhancing the abrasion resistance can be remarkably obtained when it is adhered to a recording medium containing polyvinyl chloride. can.

When the cyclic ester is blended, the content (the total amount when a plurality of types are used) with respect to the total amount of the inkjet ink composition is 2% by mass or more and 40% by mass or less, preferably 5% by mass or more and 40. It is mass% or less, more preferably 10% by mass or more and 30% by mass or less, and particularly preferably 10% by mass or more and 20% by mass or less. When the content is within the above range, it is more preferable in terms of scratch resistance, color development, ejection stability, glossiness, and suppression of uneven aggregation.

11.2. A compound represented by the formula (1).
The inkjet ink composition according to this embodiment preferably contains a compound represented by the general formula (1) (also referred to as a cyclic ester or cyclic lactone) as a solvent.

（式（１）中、Ｒ¹は炭素数１〜８のアルキル基を表し、Ｒ²およびＲ³はメチル基またはエチル基を表す。）
式（１）中、Ｒ¹は、炭素数１〜４のアルキル基であることが好ましい。「炭素数１〜４のアルキル基」は、直鎖状または分岐状のアルキル基であることができ、例えば、メチル基、エチル基、ｎ−プロピル基、ｉｓｏ−プロピル基、ｎ−ブチル基、ｉｓｏ−ブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基であることができる。Ｒ¹は、炭素数が少ない場合、炭素数が多い場合と比べて沸点が低くインク組成物の乾燥性を比較的高める点で好ましく、炭素数１が特に好ましい。Ｒ²およびＲ³も同様の点で炭素数が少ない場合好ましい。

(In the formula (1), R ¹ represents an alkyl group having 1 to 8 carbon atoms, and R ² and R ³ represent a methyl group or an ethyl group.)
In the formula (1), R ¹ is preferably an alkyl group having 1 to 4 carbon atoms. The "alkyl group having 1 to 4 carbon atoms" can be a linear or branched alkyl group, for example, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and the like. It can be an iso-butyl group, a sec-butyl group, or a tert-butyl group. When the ^{number of carbon atoms is small, R 1} has a lower boiling point than when the number of carbon atoms is large, and is preferable in that the drying property of the ink composition is relatively improved, and R 1 is particularly preferable when the number of carbon atoms is 1. R ² and R ³ are also preferable when the number of carbon atoms is small in the same respect.

The compound represented by the formula (1) has the same functions and properties as the above-mentioned cyclic ester compound, improves the abrasion resistance (rubbing fastness) and weather resistance of the image, and improves the solubility of the components contained in the ink. Although it can be improved and the ejection stability of the ink composition can be improved, the property of satisfactorily dissolving the components contained in the recording surface of the recording medium and the ink composition is further excellent. In addition, the compound represented by the formula (1) can impart appropriate pseudoplasticity to the non-aqueous ink composition, thereby ensuring good ejection stability of the ink. Since it interacts with the vinyl chloride resin, it is particularly excellent in that the ink is more firmly fixed on the surface of the recording medium containing the vinyl chloride resin.

The content of the solvent represented by the above formula (1) in the non-aqueous ink composition according to the present embodiment is 2% by mass or more and 40% by mass or less, preferably 5% by mass or more and 40% by mass or less. It is preferably 10% by mass or more and 30% by mass or less, and particularly preferably 10% by mass or more and 20% by mass or less. When the content is within the above range, it is more preferable in terms of scratch resistance, color development, ejection stability, glossiness, and suppression of uneven aggregation, and an appropriate pseudoplasticity is imparted to the non-aqueous ink composition, and ink ejection is performed. It is also preferable in that stability can be ensured.

The total content of the solvent group A in the non-aqueous ink composition is 2% by mass or more and 40% by mass or less, preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less. Yes, and particularly preferably 10% by mass or more and 20% by mass or less. When the content is within the above range, it is more preferable in terms of scratch resistance, color development, ejection stability, glossiness, and suppression of uneven aggregation.

11.3. The compound represented by the formula (2) The inkjet ink composition according to the present embodiment preferably contains a compound represented by the general formula (2) (also referred to as glycol ether) as a solvent.
R ¹ O- (R ² O) _m- R ³ ... (2)
[In the general formula (1), R ¹ and R ³ independently represent hydrogen or an alkyl group having 1 or more and 5 or less ^{carbon atoms, and R 2} represents an alkylene group having 2 or 3 carbon atoms. Represents a 2-6 integer. However, ^{at least one} of R 1 and R ³ is an alkyl group having 1 or more carbon atoms and 5 or less carbon atoms. ]

Of the above, R ¹ and R ³ are each independently preferably hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and m is preferably an integer of 2 to 3.
Here, the alkyl group having 1 or more and 5 or less carbon atoms can be a linear or branched alkyl group, and specifically, a methyl group, an ethyl group, an n-propyl group, or an iso-propyl group. , N-butyl group, sec-butyl group, or tert-butyl group. Examples of the alkylene group having 2 or 3 carbon atoms include an ethylene group (dimethylene) and a propylene group (trimethylene or methylethylene). The compound represented by the general formula (2) is an alkylene glycol alkyl ether. The compound represented by the general formula (2) may be contained alone or in combination of two or more.

Specific examples of the compound represented by the general formula (2) include diethylene glycol methyl ethyl ether (64 ° C.) (may be abbreviated as “DEGMEE” or “MEDG”), diethylene glycol dimethyl ether (56 ° C.) (“DEGdME”). (May be abbreviated as "DEGdEE" or "DEDG"), dipropylene glycol dimethyl ether (65 ° C.), diethylene glycol diethyl ether (71 ° C.), diethylene glycol monomethyl ether (105 ° C.). (Sometimes abbreviated as "DEGmME"), diethylene glycol monoisobutyl ether (112 ° C.), diethylene glycol monoisopropyl ether (101 ° C.), diethylene glycol monohexyl ether (141 ° C.), diethylene glycol butylmethyl ether (94 ° C.) (". It may be abbreviated as "DEGBME"), diethylene glycol dibutyl ether (122 ° C) (may be abbreviated as "DEGdBE"), dipropylene glycol monopropyl ether (108 ° C), dipropylene glycol monobutyl ether (117 ° C). ), Triethylene glycol monomethyl ether (139 ° C.), triethylene glycol monobutyl ether (156 ° C.), triethylene glycol dimethyl ether (113 ° C.) (may be abbreviated as "TriEGdME" or "DMTG"), tripropylene glycol. Monomethyl ether (123 ° C), tripropylene glycol monobutyl ether (138 ° C), tripropylene glycol dimethyl ether (104 ° C), tetraethylene glycol monobutyl ether (177 ° C) (abbreviated as "TerraEGmBE" or "BTG-H"). ), Tetraethylene glycol dimethyl ether (141 ° C.) (sometimes abbreviated as "TerraEGdME"), and the like. The numerical values in parentheses in the above example indicate the flash point.

The flash point of the compound in the present embodiment is the flash point by the Cleveland open flash point tester when the flash point by the tag closed flash point tester is not 80 ° C or lower, and the flash point by the tag closed flash point tester. When the temperature is 80 ° C. or lower, the flash point of the solvent at the flash point is less than 10 cSt, the flash point is set by the tag closed flash point tester, and when the flash point of the solvent is 10 cSt or more, the setter is sealed. The flash point is the flash point of the tester.

From the viewpoint of improving the drying property of the inkjet ink composition, it is preferable to use a compound having a flash point of 140 ° C. or lower among these compounds. By using a compound having a flash point of 140 ° C. or lower, the drying property of the inkjet ink composition is enhanced, uneven aggregation (aggregation of pigments, etc.) in the formed image can be less likely to occur, and scratch resistance is also excellent. It can be.

Further, these compounds can be mixed with a solvent and blended, but it is more preferable to blend a compound having a flash point of 140 ° C. or lower. When only a compound having a flash point exceeding 140 ° C. is blended, the drying of the inkjet ink composition may be delayed, the wet spreadability of the ink on the recording medium is enhanced, and the glossiness of the formed image is enhanced. On the other hand, for example, uneven aggregation (aggregation of pigments, etc.) in the formed image may occur. On the other hand, a compound having a flash point of 140 ° C. or lower improves the drying property of the inkjet ink composition, and by blending the compound, uneven aggregation (aggregation of pigment, etc.) in the formed image may be less likely to occur. can. By balancing the blending amount of the compound having a flash point of more than 140 ° C. and the compound having a flash point of 140 ° C. or less, the glossiness of the formed image can be enhanced and the aggregation unevenness can be suppressed. can. It is more preferable that the above compound contains a compound having a flash point of 70 ° C. or lower.

The content of the compound represented by the above formula (2) with respect to the total amount of the inkjet ink composition (the total amount when a plurality of types are used) is preferably 10% by mass or more and 95% by mass or less, and more. It is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, still more preferably 30% by mass or more and 75% by mass or less, and particularly preferably 40% by mass or more and 70% by mass or less. be.

Further, among the compounds of the above formula (2), the content (the total amount when a plurality of types are used) with respect to the total amount of the compound having a ignition point of 140 ° C. or lower is preferably 10% by mass. It is 95% by mass or less, more preferably 10% by mass or more and 90% by mass or less, further preferably 20% by mass or more and 80% by mass or less, and further preferably 40% by mass or more and 70% by mass or less. Further, among the compounds of the above formula (2), the content of the compound having a ignition point of 70 ° C. or less with respect to the total amount of the inkjet ink composition (the total amount when a plurality of kinds are used) is 10% by mass or more and 90. It is 0% by mass or less, preferably 20% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 70% by mass or less.

When the compound represented by the formula (1) contains a solvent having a lower flash point, the ink composition is more excellent in drying property, more excellent in suppressing uneven aggregation, and more excellent in abrasion resistance. Further, in that case, the ink composition tends to have poor color development due to poor spreadability on the surface of the recording medium of the ink composition, but even in such a case, the ink composition is pigment orange-43 (PO-43) as a pigment. ) Can be included to improve the color development property.
^{When the ink contains a glycol monoether compound in which any of R 1} and R ³ is hydrogen among the compounds represented by the formula (1), in addition to the above-mentioned effects, the aggregation unevenness tends to be particularly excellent, which is preferable. When the ink contains a glycol monoether compound, the content thereof is preferably 2 to 20% by mass, more preferably 3 to 15% by mass, still more preferably 3 to 10% by mass in the above points. The flash point of the glycol monoether compound does not matter.

1.1.4. Other Solvents In addition to the above, the following compounds can be used as the solvent in the inkjet ink composition according to the present embodiment.

Examples of such a solvent include alcohols (methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol, fluoroalcohol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), and carboxylic acid esters (acetic acid). Methyl, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, etc.), ethers (diethyl ether, dipropyl ether, tetrahydrofuran, dioxane, etc.), polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, etc.) , Polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, trimethylolpropane, etc.) and the like.

Further, (polyvalent) alcohols may be contained as the solvent. Examples of (polyvalent) alcohols include glycerin, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and 3-methyl-. 1,3-Butanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2, Examples thereof include 2-dimethyl-1,3-propanediol and 2-methylpentane-2,4-diol.

When the inkjet ink composition contains (polyvalent) alcohols, the total content includes the effect of improving wet spreadability and permeability on the recording medium to reduce shading unevenness, storage stability, and storage stability. From the viewpoint of ensuring ejection reliability, it is preferably 0.05% by mass or more and 30% by mass or less, and 0.1% by mass or more and 30% by mass or less, based on the total mass of the inkjet ink composition. More preferred. When the content of (multivalent) alcohols is within the above range, the wettability, permeability, and dryness of the ink are improved, and an image having good print density (color development) may be obtained. .. Further, when the content of the (multivalent) alcohol is within the above range, the viscosity of the ink can be made appropriate, and the occurrence of nozzle clogging or the like may be reduced.

In addition, amines may be blended in the inkjet ink composition, for example, triethanolamine, tripropanolamine, tributanolamine, N, N-dimethyl-2-aminoethanol, N, N-diethyl-2-. Examples thereof include hydroxylamines such as aminoethanol, and one or more kinds can be used. When the amines are contained, the total content is preferably 0.05% by mass or more and 5% by mass or less, and 0.1% by mass or more and 3% by mass or less, based on the total mass of the inkjet ink composition. Is more preferable.

Further, as a solvent, higher fatty acid esters such as methyl laurate, isopropyl hexadecanoate (isopropyl palmitate), isopropyl myristate, methyl oleate, ethyl oleate and the like, and dicarboxylic acids (carbons) of aliphatic hydrocarbons having 2 to 8 carbon atoms. The number is a dibasic acid diester obtained by diestering an alkyl group having 1 to 5 carbon atoms (excluding the carbon of the carboxyl group), and a monocarboxylic acid of an aliphatic hydrocarbon having 6 to 10 carbon atoms (the number of carbon atoms is a carboxyl group). Amidated (excluding carbon) alkylamides (N, N-dimethyldecaneamide, etc.) in which the substituents substituting the amide nitrogen atom are independently hydrogen atoms and alkyl groups having 1 to 4 carbon atoms. And so on.

As the other solvents exemplified here, one kind or a plurality of kinds can be added to the inkjet ink composition in an appropriate blending amount.

1.2. Pigments The inkjet ink composition of this embodiment is used as a pigment in C.I. I. Pigment Orange-43 (PO-43) is preferably included. C. I. By including Pigment Orange-43 (PO-43), the recorded material can be obtained with excellent weather resistance suitable for outdoor use and a wide color reproduction range of warm colors.

PO-43 is a pigment of CAS Registry Number 4424-06-0, and the chemical name is benzimidazole [2,1-b: 2', 1'-i] benzo [lmn] [3,8] phenanthroline. -8,17-dione or 1,8- (1H-benzimidazole-2,1-diylcarbonyl) -5,4- (1H-benzimidazole-2,1-diylcarbonyl) naphthalene. PO-43 has a penorin structure and is given the generic name "penorin orange". The hue of PO-43 is a bright reddish orange. "CI is an abbreviation for Color Index. A non-aqueous inkjet ink composition contains CI Pigment Orange-43 (Pigment Orange-43, PO-43) to provide a warm color. It is possible to widen the reproduction area and record a recorded material with excellent weather resistance and color development. Excellent color development means that the ink on the recording medium required for printing at a predetermined density is required. It is advantageous in that the amount of adhesion can be reduced. The small amount of ink adhered is advantageous in terms of accelerating drying and improving image quality by reducing uneven aggregation and the like, and is also advantageous in terms of reducing printing costs.

The warm color reproduction region is recommended by the CIE (International Commission on Illumination), and in the L ^* a ^* b ^* color system, both a ^* and b ^* refer to the positive range. In this embodiment, C.I. I. The ink composition containing Pigment Orange-43 is also referred to as a specific non-aqueous ink composition. C.I. I. The ink composition containing Pigment Orange-43 is at least C.I. I. It may contain Pigment Orange-43, and may be orange ink, yellow ink, red ink, magenta ink, or the like. It may be used as an ink particularly used for printing warm colors as compared with the basic color ink described later. In particular, since the orange color reproduction area is wide, it is particularly useful when using orange ink (orange ink composition). Orange ink is an ink used for coloring oranges. The orange ink is at least orange ink when the product name is orange ink or an ink having a product name having a substantially similar meaning thereof. Further, the ink particularly used for orange printing as compared with the basic color ink described later corresponds to this.

Commercially available products can be used for PO-43, for example, "Hostaperm Orange" and "PV Gast Orange GRL" manufactured by Clariant, "Fasogen Super Orange 6200" manufactured by DIC Corporation, and "Lionogen Orange" manufactured by Toyo Ink Co., Ltd. It can be obtained as "GR-F" or the like.

The volume average particle size of PO-43 contained in the inkjet ink composition of the present embodiment is preferably 100 nm or more and 400 nm or less, and more preferably 150 nm or more and 300 nm or less in terms of ejection stability, weather resistance and color development. .. Here, the volume average particle size of the pigment can be evaluated by a laser diffraction / scattering method. Specifically, the inked sample (pigment) is diluted with DEGdEE (diethylene glycol diethyl ether) to 1000 ppm or less, and this is diluted with a laser diffraction / scattering measuring device (for example, Microtrac UPA250 (manufactured by Nikkiso Co., Ltd.)). )) Can be measured by reading the value of the median diameter D50 in an environment of 20 ° C. Therefore, even when PO-43 having different volume average particle diameters are mixed and used, the volume average particle diameter of each and the volume average particle diameter of the mixture can be measured.

The content of PO-43 with respect to the total amount of the inkjet ink composition of the present embodiment is preferably 0.05% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 10% by mass or less. , More preferably 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 8% by mass or less, and particularly preferably 3% by mass or more and 7% by mass or less.

On the other hand, the inkjet ink composition of the present embodiment may further contain a coloring material other than the above-mentioned PO-43. Examples of such a coloring material include pigments and dyes having a hue similar to that of PO-43, for example, in the color index number, C.I. I. Pigment orange numbered pigments and C.I. I. Examples include those given a Pigment Red number.

1.3. Fixing Resin The inkjet ink composition according to this embodiment preferably contains a fixing resin. The fixing resin is a resin that protects and adheres solids contained in ink such as pigments to a recording medium to improve abrasion resistance. Examples of the fixing resin that can be used include vinyl chloride resin, (meth) acrylic resin, urethane resin, polyether resin, polyester resin and the like. When the solvent contained in the ink is the solvent of the solvent group A, the fixing resin is satisfactorily dissolved and can be dissolved in the ink. As a result, the ink can be firmly fixed on the surface of the recording medium by the fixing resin, and the recorded material has excellent abrasion resistance. In addition, the fixing resin does not completely dissolve in the ink and becomes a foreign substance, which lowers the ejection stability at the time of inkjet ejection. There is no. Among the fixing resins, vinyl chloride-based resin and (meth) acrylic-based resin are particularly excellent in solubility in a solvent, particularly solvent group A, and particularly excellent in abrasion resistance, and are preferable.

Examples of the vinyl chloride resin include a vinyl chloride polymer and a vinyl chloride copolymer, and examples of the vinyl chloride copolymer include a copolymer containing vinyl chloride and vinyl acetate. When the solvent contained in the ink is the solvent of the solvent group A, the copolymer containing vinyl chloride and vinyl acetate has particularly excellent solubility and can be satisfactorily dissolved in the ink. As a result, the ink can be firmly fixed on the surface of the recording medium containing the vinyl chloride resin by the copolymer containing vinyl chloride and vinyl acetate dissolved in the solvent.

The vinyl chloride resin can be obtained by a conventional method, for example, by suspension polymerization. Specifically, water, a dispersant, and a polymerization initiator are charged in the polymerizer, and after degassing, vinyl chloride and vinyl acetate are press-fitted for suspension polymerization, or a part of vinyl chloride and vinyl acetate are press-fitted. Then, the reaction can be started, and suspension polymerization can be carried out while the remaining vinyl chloride is press-fitted during the reaction.

The vinyl chloride-based resin preferably contains 70 to 90% by mass of vinyl chloride units as its composition. Within the above range, it is stably dissolved in the inkjet ink composition, so that it is excellent in long-term storage stability. Further, it has excellent ejection stability and can obtain excellent fixability to a recording medium.

The vinyl chloride-based resin may include, if necessary, other structural units together with the vinyl chloride unit and the vinyl acetate unit, and examples thereof include a carboxylic acid unit, a vinyl alcohol unit, and a hydroxyalkyl acrylate unit. Particularly, the vinyl alcohol unit is preferably mentioned. It can be obtained by using the monomer corresponding to each of the above-mentioned units. Specific examples of the monomer giving a carboxylic acid unit include maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, acrylic acid, and methacrylic acid. Specific examples of the monomer giving a hydroxyalkyl acrylate unit include hydroxyethyl (meth) acrylate, hydroxyethyl vinyl ether and the like. The content of these monomers is not limited as long as the effect of the present invention is not impaired, but for example, copolymerization can be carried out in the range of 15% by mass or less of the total amount of the monomers.

As the vinyl chloride resin, commercially available ones may be used, and examples thereof include sorbine CN, sorbine CNL, sorbine C5R, sorbine TA5R, and sorbine CL (all manufactured by Nisshin Kagaku Kogyo Co., Ltd.).

The average degree of polymerization of the vinyl chloride resin is not particularly limited, but is preferably 150 to 1100, more preferably 200 to 750. When the average degree of polymerization is in the above range, the vinyl chloride resin is stably dissolved in the ink composition of the present embodiment, and is therefore excellent in long-term storage stability. Further, it has excellent ejection stability and can obtain excellent fixability to a recording medium. The average degree of polymerization of the vinyl chloride resin is calculated by measuring the specific viscosity, and can be obtained according to the method for calculating the average degree of polymerization described in "JISK6720-2".

The number average molecular weight of the vinyl chloride resin is not particularly limited, but is preferably 1000 to 50000, and more preferably 12000 to 42000. The number average molecular weight can be measured by GPC and can be obtained as a relative value in terms of polystyrene.
The content of the vinyl chloride resin in the inkjet ink composition is, for example, 0.05 to 10% by mass, preferably 0.5 to 5% by mass, more preferably 0.5 to 3% by mass, and further preferably 0. It can be 5 to 2.5% by mass, and more preferably 1 to 2% by mass. When the content is in the above range, the solubility in the solvent is good, the ejection stability of the ink is excellent, the fixing property particularly excellent to the recording medium is obtained, and the scratch resistance is excellent. Further, when the content is within the above range, the recorded material does not appear whitish and muddy, and excellent color development can be obtained. This is especially true for C.I. I. In the case of an ink containing Pigment Orange-43, it is particularly preferable to obtain excellent color development of warm colors.

The (meth) acrylic resin ((meth) acrylic resin) means an acrylic resin or a methacrylic resin. It is a polymer of a (meth) acrylic monomer or a copolymer of a (meth) acrylic monomer and another monomer. Examples of the (meth) acrylic resin include alkyl- (meth) acrylates such as ethyl-, propyl-, and butyl- (meth) acrylate: hydroxymethyl-, hydroxyethyl-, hydroxypropyl-, hydroxybutyl-, and hydroxypentyl. Examples thereof include homopolymers such as hydroxyalkyl (meth) acrylates such as − (meth) acrylates or copolymers thereof, but methyl (meth) acrylate homopolymers, and methyl (meth) acrylates and butyl (meth). Preferables are acrylate copolymers, methyl (meth) acrylate and ethyl (meth) acrylate copolymers, and methyl (meth) acrylate and propyl (meth) acrylate copolymers.
Examples of the copolymer of the (meth) acrylic monomer and the other monomer include an olefin (meth) acrylic copolymer resin such as a styrene (meth) acrylic copolymer resin. The mass ratio of the (meth) acrylic monomer in the copolymer of the (meth) acrylic monomer and the other monomer is preferably 30% by mass or more, more preferably 50% by mass or more.

Examples of commercially available (meth) acrylic resins include "Paraloid B99N" (methyl methacrylate / butyl methacrylate copolymer) Tg 82 ° C., weight average molecular weight 15,000) and "Paraloid B60" (methylmetha) manufactured by Roam & Haas. Acrylate / butyl methacrylate copolymer) Tg 75 ° C., weight average molecular weight 50,000) and the like are exemplified.

The (meth) acrylic resin is a radical polymerization initiator in the polyoxyethylene glycol dialkyl ether represented by the general formula (1) or the polyoxyethylene (alkylene) glycol alkyl ether acetate represented by the general formula (3). It is preferable to obtain a (meth) acrylic resin obtained by solution polymerization using.

By forming the (meth) acrylic resin by solution polymerization, the solubility in a solvent can be improved, and an inkjet ink composition having good ejection stability, abrasion resistance, and resolubility can be obtained.

The molecular weight of the (meth) acrylic resin and the glass transition temperature (Tg) are arbitrary, but the polystyrene-equivalent weight average molecular weight of the (meth) acrylic resin is 8,000 to 100,000, preferably 10,000 to 60,000. Is. Further, the glass transition temperature (Tg) of the (meth) acrylic resin is preferably 70 ° C. or higher, particularly preferably 80 ° C. or higher. The upper limit of the glass transition temperature is about 120 ° C. When the weight average molecular weight or Tg is within the above range, the effect of obtaining good ink storage stability and good printed matter such as drying property and concealing property becomes particularly remarkable, which is preferable.

The content of the (meth) acrylic resin in the inkjet ink composition is, for example, 0.05 to 10% by mass, preferably 0.5 to 7% by mass, more preferably 1 to 6% by mass, still more preferably 2. It can be ~ 5% by mass, particularly preferably 2.5 to 5% by mass, still more preferably 2.5 to 4.5% by mass, and even more preferably 3 to 4.5% by mass. When the content is in the above range, the solubility in the solvent is good, the ejection stability of the ink is excellent, the fixability to the recording medium is excellent, and the scratch resistance is excellent.

Other fixing resins may be contained in the ink. Examples of other resins include rosin modified resins, phenol resins, terpene resins, urethane resins, polyester resins, polyether resins, polyamide resins, epoxy resins, fibrous resins such as cellulose acetate butyrate, and vinyl toluene-α. -Methylstyrene copolymer resin and the like are mentioned, and urethane resin, polyester resin and polyether resin are preferable in terms of excellent solubility and abrasion resistance.

The content of the fixing resin in the inkjet ink composition is, for example, 0.05 to 10% by mass, preferably 0.5 to 7% by mass, more preferably 1 to 6% by mass, and further preferably 2 to 5% by mass. Can be. When the content of the fixing resin is within the above range, the solubility in a solvent is good, the ink ejection stability is excellent, the fixing property to a recording medium is excellent, and the scratch resistance is excellent.

In the inkjet ink composition, the ratio of the total content of the fixing resin to the total content of the solvent group A is preferably 0.1 to 1.5, preferably 0.1 to 1.0, based on the mass. More preferably, 0.2 to 0.5 is further preferable, and 0.3 to 0.5 is particularly preferable. Within the range of the amount ratio, the fixing resin can be easily dissolved in the solvent, the nozzles are less likely to be clogged, and the ink fixing property on the surface of the recording medium can be sufficiently improved. In terms of the content and amount ratio of the fixing resin described above, it is more preferable to use a vinyl chloride resin and / or a (meth) acrylic resin as the fixing resin in the above points.
When the ink contains a vinyl chloride resin and a (meth) acrylic resin as the fixing resin, it is preferable in that the scratch resistance, the weather resistance, the ejection stability and the like can be well-balanced and excellent.

1.4. Others (surfactant)
In addition to the organic solvent, the inkjet ink composition according to the present embodiment contains a silicon-based surfactant, a fluorine-based surfactant, or a fluorine-based surfactant from the viewpoint of reducing surface tension and improving wettability with a recording medium. A polyoxyethylene derivative which is a nonionic surfactant may be added.

As the silicon-based surfactant, it is preferable to use polyester-modified silicon or polyether-modified silicon. Specific examples include BYK-347, 348, BYK-UV3500, 3510, 3530, and 3570 (all manufactured by Big Chemie Japan).

As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and specific examples thereof include BYK-340 (manufactured by Big Chemie Japan).

Further, as the polyoxyethylene derivative, it is preferable to use an acetylene glycol-based surfactant. Specific examples include Surfinol (registered trademark) 82, 104, 465, 485, TG (all manufactured by Air Products Japan), Orfin (registered trademark) STG, E1010 (all manufactured by NOF CORPORATION), and Nissan. Nonion (registered trademark) A-10R, A-13R (all manufactured by NOF Corporation), Floren TG-740W, D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Neugen (registered trademark) CX-100 (Daiichi Kogyo) (Made by Pharmaceutical Co., Ltd.) and the like.

The content of the surfactant in the inkjet ink composition according to the present embodiment is preferably 0.05% by mass or more and 3% by mass or less, and more preferably 0.5% by mass or more and 2% by mass or less.

(Dispersant)
In the inkjet ink composition according to the present embodiment, any dispersant used in a normal ink composition can be used from the viewpoint of improving the dispersion stability of the pigment. Specific examples of such dispersants include polyester polymers such as Hinoact KF1-M, T-6000, T-7000, T-8000, T-8350P, and T-8000E (all manufactured by Takefu Fine Chemical Co., Ltd.). Compounds, Solsperse 20000, 24000, 32000, 32500, 33500, 34000, 35200, 37500 (all "Solspers" manufactured by LUBRIZOL), Disperbyk-161, 162, 163, 164, 166, 180, 190, 191 and 192 (all). Big Chemie Japan Co., Ltd.), Floren DOPA-17, 22, 33, G-700 (all manufactured by Kyoeisha Chemical Co., Ltd.), Azispar PB821, PB711 (all manufactured by Ajinomoto Co., Inc.), LP4010, LP4050, LP4055, POLYMER400, Examples thereof include 401, 402, 403, 450, 451 and 453 (all manufactured by EFKA Chemicals Co., Ltd.).

Further, as the dispersant, a metal soap, a polymer dispersant having a basic group, or the like can be used, and a polymer dispersant having a basic group is preferable. In particular, those having an amino group, an imino group or a pyrrolidone group as a basic group are preferable. As the polymer dispersant having a basic group, polyalkylene polyamines, salts of long-chain polyaminoamides and high molecular weight acid esters, salts of polyaminoamides and polar acid esters, modified polyurethanes, polyester polyamines and the like can be used.

Specific examples of the polymer dispersant having a basic group include "Anti-Terra-U (polyaminoamidophosphate)" and "Anti-Terra-204 (high molecular weight polycarboxylate)" manufactured by BYK Chemie. "Disperbyk-101 (polyaminoamidophosphate and acid ester) 130 (polyamide) can be mentioned. Also, Solsperth 5000 (phthalocyanine ammonium salt-based), 13940 (polyesterpolyimine), 17,000, 18,000, manufactured by Abyssia. 19000 (polyester polyamine) and 11200 (polyester polyimine) can be mentioned, and V-216 and V-220 (polyvinylpyrrolidone having a long-chain alkyl group) manufactured by ISP can be mentioned.

In the ink composition according to the present embodiment, the content of the dispersant when the dispersant is used can be appropriately selected depending on the pigment contained in the ink composition, but the content of the pigment in the ink composition is 100 parts by mass. On the other hand, it is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 30 parts by mass or more and 120 parts by mass or less. As the pigment dispersant, one suitable for excellent dispersion stability may be used depending on the pigment to be used.

(others)
In addition to the above components, the inkjet ink composition of the present embodiment imparts predetermined performance such as a chelating agent such as ethylenediaminetetraacetic acid salt (EDTA), a preservative / antifungal agent, and a rust preventive agent. Can contain substances for

2. 2. Ink set The ink set according to the present embodiment is a non-aqueous inkjet ink composition containing a solvent and a pigment containing Pigment Orange-43 (PO-43), and a non-aqueous cyan ink set containing the solvent and the pigment. A warm color reproduction range is such that an ink set comprising at least a composition, a non-aqueous magenta inkjet ink composition containing a solvent and a pigment, and a non-aqueous yellow inkjet ink composition containing a solvent and a pigment is provided. It is preferable in that it is wide and has excellent weather resistance of recorded materials. In the ink set, it is particularly preferable to use a non-aqueous inkjet ink composition containing a solvent and a pigment containing Pigment Orange-43 (PO-43) as the orange ink composition. Hereinafter, a non-aqueous inkjet ink composition containing a solvent and a pigment containing Pigment Orange-43 (PO-43) is also described as an orange ink composition, but is not limited to the orange ink composition.

The non-aqueous orange inkjet ink composition is preferable in that it exhibits the above-mentioned effects when it is the above-mentioned inkjet ink composition containing Pigment Orange-43 (PO-43) as a solvent and a pigment. The non-aqueous cyan inkjet ink composition, the non-aqueous magenta inkjet ink composition, and the non-aqueous yellow inkjet ink composition (hereinafter referred to as basic color inks) use cyan pigments, magenta pigments, and yellow pigments as pigments, respectively. Other than the inclusion, the above-mentioned inkjet ink composition can be obtained, which is preferable in that the above-mentioned effects can be obtained.

As the pigment contained in the basic color ink composition, a pigment such as a colored inorganic pigment or a colored organic pigment usually used in a conventional non-aqueous ink composition can be used. Examples of the pigment include azo pigments such as azolake, insoluble azo pigment, condensed azo pigment, and chelate azo pigment; phthalocyanine pigment, perylene and perylene pigment, anthraquinone pigment, quinacridone pigment, dioxandine pigment, thioindigo pigment, isoindolinone pigment, and quinophthaloni. Polycyclic pigments such as pigments; dye lakes such as basic dye type rakes and acidic dye type rakes; organic pigments such as nitro pigments, nitroso pigments, aniline blacks and daylight fluorescent pigments; inorganic pigments such as carbon blacks. Be done. The average primary particle size of the pigment particles is not particularly limited, but is preferably 50 nm or more and 500 nm or less.

Examples of the magenta pigment used for the magenta ink include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139, C.I. I. Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I. I. Pigment Red 170, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 194, C.I. I. Pigment Red 209, C.I. I. Pigment Red 222, C.I. I. Pigment Red 224 and the like.

Examples of the yellow pigment used for the yellow ink include C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 138, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 180 and the like.

Examples of the cyan pigment used for the cyan ink include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7, C.I. I. Pigment Green 36, C.I. I. Pigment Blue 15: 4 and the like.

The pigment of the basic color ink may be used alone or in combination of two or more with respect to the ink. The content of the pigment in the ink composition is preferably 0.5 to 25% by mass, more preferably 1 to 15% by mass, still more preferably 2 to 10% by mass, and particularly preferably 3 to 7% by mass.

When the basic color ink and the non-aqueous orange inkjet ink composition each contain the solvent of the above-mentioned solvent group A, they are preferable in that they are excellent in weather resistance, rubbing resistance, ejection stability and the like. In particular, the inclusion of the solvent of Solvent Group A promotes the penetration of ink into the recording medium, which is also preferable in terms of reducing the unevenness of ink aggregation, and recording of colors of secondary color or higher using a plurality of inks. This is preferable in that it reduces the problem that the ink aggregates and a clean secondary color cannot be obtained. Further, when the solvent contains one or more of the compounds represented by the above-mentioned general formula (2), the characteristics of the ink composition, for example, drying property, suppression of uneven aggregation, glossiness, color development and the like. Among the compounds represented by the general formula (2), those having a flash point of 140 ° C. or lower, further 70 ° C. or lower, or glycol monoether are more preferable. When the solvent contains one or more of the above-mentioned solvent of solvent group A and one or more compounds represented by the general formula (2), particularly preferable ones, the content thereof is preferably in the above-mentioned range.

When the basic color ink and the non-aqueous orange inkjet ink composition each contain at least one of the above-mentioned solvents of the solvent group A as the solvent, they are preferable in that they are more excellent in abrasion resistance, weather resistance, and ejection stability. When one or more of the solvent group A is contained as the solvent, the content thereof is preferably in the above range.

The inset of the present embodiment may further include another non-aqueous inkjet ink composition. Examples of other non-aqueous inkjet ink compositions include ink compositions containing pigments different from those described above, clear ink compositions not used for coloring, and the like. The composition of the other non-aqueous inkjet ink composition other than the pigment type can be the same as that of the above-mentioned inkjet ink composition. For example, when a non-aqueous inkjet black ink composition containing a black pigment is provided, ^{the color reproduction range of a dark color system (a color region having a low L *} value) is wide and preferable. Examples of the black pigment include carbon black (CI pigment black 7) and the like.

3. 3. Inkjet Recording Method The inkjet recording method according to the present embodiment is characterized in that the above-mentioned inkjet ink composition or ink set is used to record on a recording medium by an inkjet method. According to the inkjet recording method according to the present embodiment, since the above-mentioned inkjet ink composition or ink set is used, it is possible to form an image having good weather resistance and a wide warm color reproduction region, and moreover, stable inkjet. Recording is possible, and images with good image quality and robustness can be recorded. As the recording medium, a vinyl chloride-based recording medium is preferable in the above points.

When the ink of the inkjet ink composition or the ink set contains the solvent of the solvent group A, the solvent interacts with the vinyl chloride resin. Therefore, the inkjet recording method according to the present embodiment is firmly fixed on the recording medium when the above-mentioned droplets of the inkjet ink composition are attached to the surface of the vinyl chloride-based recording medium to record an image. Excellent in terms of points.

The vinyl chloride-based recording medium in the inkjet recording method according to the present embodiment is not particularly limited as long as it contains a vinyl chloride-based resin. Examples of the recording medium containing the vinyl chloride resin include a hard or soft vinyl chloride film or a sheet. The above-mentioned inkjet ink composition enables recording of an image on an untreated surface of a vinyl chloride resin base material, and does not require the use of an expensive recording medium like a conventional recording medium having a receptive layer. However, it goes without saying that it can be applied even to a substrate surface-treated with an ink receiving layer.

The inkjet recording apparatus used in the inkjet recording method according to the present embodiment is not particularly limited, but a drop-on-demand type inkjet recording apparatus is preferable. The drop-on-demand type inkjet recording device employs a piezoelectric element recording method that records using a piezoelectric element arranged in the recording head, heat generated by a heater of a heat generating resistance element arranged in the recording head, or the like. There are some that adopt a heat jet recording method that records using energy, but any recording method can be adopted. Further, since the inkjet ink composition according to the present embodiment has the advantage of being inactive with respect to the ink-repellent treated ejection nozzle surface, for example, an inkjet recording head having an ink-repellent treated ejection nozzle surface. It can be advantageously used in the inkjet recording method of ejecting from the ink jet.

3. 3. Examples The present invention will be further described with reference to Examples, but the present invention is not limited to the following examples.

3.1. Ink composition example 3.1.1. Preparation of Pigment Dispersion Liquid Pigment Orange 43 (PO-43) having a primary particle size of 160 nm was prepared as a pigment. Solsperse 17000 (polyester polyamine manufactured by Lubrizol) was used as the dispersant, and the amount of the dispersant added to the pigment within the same mass range was used to prepare a dispersion. As the dispersion medium, the solvent having the highest content as a solvent was used as the dispersion medium for each ink composition example to prepare a pigment dispersion liquid. Pigment oranges 31, 64, and 71 were also obtained with pigment dispersions in the same manner. The volume average particle size of each pigment was about 200 nm.

3.1.2. Preparation of Ink Composition Using the pigment dispersion prepared above, ink compositions having different pigments and compositions with the material compositions shown in the table were prepared. For each ink composition, the materials shown in the table are placed in a container, mixed and stirred with a magnetic stirrer for 2 hours, and then filtered with a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles. Prepared by. The numerical values in the composition column in the table indicate mass%.

The abbreviations or product names shown in the table are as follows.
<Pigment>
-PO-43: C.I. I. Pigment Orange 43
-PO-31: C.I. I. Pigment Orange 31
-PO-64: C.I. I. Pigment Orange 64
-PO-71: C.I. I. Pigment Orange 71
<Cyclic ester solvent>
・ Gamma-Butyrolactone: Product name, manufactured by Kanto Chemical Co., Inc. ・ σ-Valerolactone: Product name, manufactured by Kishida Chemical Co., Ltd. <General formula (1) solvent>
-M100: Product name, manufactured by Idemitsu Kosan.
-B100: Product name, manufactured by Idemitsu Kosan.

<General formula (2) solvent>
-DEGMEE: Diethylene glycol methyl ethyl ether, trade name "Highsolve EDM", manufactured by Toho Chemical Industry Co., Ltd., flash point 64 ° C)
-DEGdME: Diethylene glycol dimethyl ether, trade name "diethylene glycol dimethyl ether", manufactured by Tokyo Chemical Industry Co., Ltd., flash point 56 ° C)
-DEGDEE: Diethylene glycol diethyl ether, trade name "diethylene glycol diethyl ether", manufactured by Tokyo Chemical Industry Co., Ltd., flash point 71 ° C)
DEGBME: Diethylene glycol butylmethyl ether, trade name "Highsolve BDM", manufactured by Toho Chemical Industry Co., Ltd., flash point 94 ° C.)
-TriEGdME: Triethylene glycol dimethyl ether, trade name "Triethylene glycol dimethyl ether", manufactured by Kishida Chemical Co., Ltd., flash point 113 ° C)
-TetraEGdME: Tetraethylene glycol dimethyl ether, trade name "Tetraethylene glycol dimethyl ether", manufactured by Tokyo Chemical Industry Co., Ltd., flash point 141 ° C.)
-TetraEGmBE: Tetraethylene glycol monobutyl ether, trade name "Buchisenol 40", manufactured by KH Neochem Co., Ltd., flash point 177 ° C)
<Other solvents>
-AF-7: Naphthenic hydrocarbon solvent manufactured by JX Nippon Oil & Energy Co., Ltd.
-Isooctyl palmitate: A fatty acid ester solvent manufactured by Nikko Chemicals.

<Pigment dispersant>
-Solsperse 17000: Product name, manufactured by Lubrizol, polyester polyamine <surfactant>
-BYK340: Product name, manufactured by Big Chemie Japan Co., Ltd., Silicon-based surfactant <fixing resin>
-Solvine CL: trade name, manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride-vinyl acetate copolymer-Paraloid B60: trade name, manufactured by Dow Chemical Co., Ltd., (meth) acrylic resin.

3.1.3. Evaluation test 3.1.3.1. Weather resistance Using each of the prepared ink compositions, use an inkjet printer (manufactured by Seiko Epson Corporation, model "SC-S70650") to set the Duty so that the initial OD values are 0.5, 1.0, and the maximum value. Printing was performed while adjusting. The recording resolution was 1440 × 1440 dpi. A glossy polyvinyl chloride sheet (Roland DG, model number SV-G-1270G) was used as the recording medium. The obtained recorded material was left to dry in a general environment for 1 hour. After that, the obtained recorded material is put into the chamber of the xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), and "light irradiation 25 minutes" → "light irradiation + water rainfall 20 minutes" → "light irradiation 30 minutes" → A cycle test of "60 minutes of water rainfall" was conducted. This cycle test was carried out continuously for 4 weeks, and the record was taken out after 4 weeks. For each recorded material taken out, the OD value was measured using a Gretag densitometer (manufactured by Gretag Macbeth), the residual rate (%) of the OD value was obtained, and the initial OD values were 0.5, 1.0, and the maximum value. Of the three types of recorded materials, the one with the lowest residual rate was evaluated. The weather resistance was determined based on the following criteria. The results are shown in the table.
5: OD value residual rate is 90% or more 4: OD value residual rate is 87% or more and less than 90% 3: OD value residual rate is 84% or more and less than 87% 2: OD value residual rate is 81% or more and less than 84% 1 : OD value residual rate is less than 81%

3.1.3.2. Discharge stability (intermittent evaluation)
The frequency of the piezo element mounted on the inkjet printer (manufactured by Seiko Epson Corporation, model "SC-S70650") is set to 7 kHz, and the drive waveform is optimized from each nozzle of the head for each ink composition. The droplets were continuously ejected for 250 seconds, and then the droplet ejection was interrupted for 300 seconds (1 sequence). After that, in the same manner, the operations of continuous ejection of droplets and interruption of ejection were repeated for 10 sequences. At the end of 10 sequences, printing stability evaluation (intermittent evaluation) was performed by counting the number of non-ejection nozzles in 360 nozzles. The evaluation results are shown in the table. The evaluation criteria are as follows.
4: Number of non-discharge nozzles is 0 3: Number of non-discharge nozzles is 1-2 2: Number of non-discharge nozzles is 3-4 1: Number of non-discharge nozzles is 5 or more

3.1.3.3. Gloss (image quality)
Using the above printer, each ink composition of Examples and Comparative Examples was solid-printed on a glossy polyvinyl chloride sheet (Roland DG, model number SV-G-1270G) at a recording resolution of 1440 × 1440 dpi at 100% density. Then, it was dried at 25 ° C.-65% RH (relative humidity) for 1 day to prepare a record of each example. The glossiness of the 20 ° reflection on the recording surface was measured using the gloss meter MULTI Gloss 268 (manufactured by Konica Minolta) on the recorded material thus obtained. The evaluation results are shown in the table. The evaluation criteria are as follows.
4: 50 or more 3: 40 or more and less than 50 2: 30 or more and less than 40 1:30

3.1.3.4. Aggregation unevenness Recorded materials of each example were prepared in the same manner as in the above-mentioned "evaluation of glossiness". The uneven aggregation of the pigment on the recording surface of the recorded material thus obtained was visually observed to evaluate the uneven aggregation. The evaluation results are shown in the table. The evaluation criteria are as follows.
4: No uneven aggregation is observed.
3: Aggregation unevenness is observed in magnified observation.
2: Some uneven aggregation is observed.
1: Conspicuous aggregation unevenness.

3.1.3.5. Abrasion resistance Recorded materials of each example were prepared in the same manner as in the above-mentioned "evaluation of glossiness". The recorded material thus obtained has abrasion resistance according to JIS K5701 (ISO 11628) using a Gakushin type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., trade name "AB-301"). Was evaluated. That is, a cotton cloth was placed on the recording surface of the recorded material, reciprocated 20 times with a load of 500 g, and rubbed, and the peeled state of the recording surface of the recorded material after rubbing was visually observed. The evaluation results are shown in the table. The evaluation criteria are as follows.
3: There is no dirt on the cotton cloth. There are no scratches on the recording surface.
2: There is a record on the cotton cloth. There are almost no scratches on the recording surface.
1: There is a record on the cotton cloth. There are scratches on the recording surface.

3.1.3.6. Color development The printing was performed in the same manner as in the above weather resistance evaluation, and the initial OD value was measured in the same manner. However, the amount of ink adhered to the recording medium was 8 mg / inch ^{2 in} each example, and the recording resolution was 1440 × 1440 dpi. The evaluation results are shown in the table.
4: Initial OD value is 1.0 or more and 3: Initial OD value is 0.85 or more and less than 1.0 2: Initial OD value is 0.7 or more and less than 0.85 1: Initial OD value is less than 0.7

3.1.4. Evaluation Results Compositions 1 to 16, which are ink compositions containing solvent group A and pigment orange 43, all showed excellent weather resistance, scratch resistance, and color development. On the other hand, the solvent-free ink composition 17 of the solvent group A was inferior in scratch resistance, and the compositions 18 to 20 not containing pigment orange 43 were inferior in either weather resistance or color development. The ink composition 21 containing neither the solvent of the solvent group A nor the pigment orange 43 had relatively good color development property as compared with the composition 20, but was inferior in scratch resistance. Further, the ink composition 16 containing a relatively large amount of vinyl chloride resin tended to have a slightly inferior color development property, but the recorded material appeared white and cloudy, and it is presumed that the color development property was slightly inferior. From this, it was found that there is a particularly preferable range of the vinyl chloride resin, particularly in the case of obtaining excellent warm color development as an ink containing Pigment Orange 43.

3.2. Ink set example 3.2.1. Preparation of Ink Compositions The types of pigments and pigment dispersants were changed, and ink compositions 22 to 25 of other colors were prepared in the same manner as in the above-mentioned ink composition examples. As the pigment dispersion liquid, a pigment dispersant suitable for each pigment was used.
<Pigment>
・ P. B. 15: 3 C.I. I. Pigment Blue 15: 3
・ P. R. 122: C.I. I. Pigment Red 122
・ P. Y. 155: C.I. I. Pigment Yellow 155
・ CB: Carbon black pigment

3.2.2. Evaluation test 3.2.2.1. Weather resistance Printing was performed in the same manner as in the weather resistance evaluation of the above-mentioned ink composition example. ^{However, C *} = √ when the hue angle on the a ^* b ^{* plane formed by the L *} value of 70 and a ^* b ^* is 45 °, which enables color reproduction on a recording medium using the ink provided in each ink set. The printed matter of the color having the largest value of (a ^{* 2} + b ^{* 2) was printed and used for evaluation.} A spectrophotometric system (manufactured by Konica Minolta) was used to confirm the L ^* a ^* b ^{* values at that time.} The weather resistance acceleration test, OD value measurement, and evaluation criteria were performed in the same manner as in the weather resistance evaluation of the ink composition example. The evaluation results are shown in the table.

3.2.2.2. Gamut volume Printing was performed in the same manner as in the above weather resistance evaluation. However, all the colors capable of color reproduction were printed on the recording medium using the ink of each ink set, and ^{the gamut volume of the printable L *} a ^* b ^* color space was calculated. The results are shown in the table.

3.2.2.3. Aggregation unevenness Printing and evaluation were performed in the same manner as in the above-mentioned aggregation unevenness evaluation of the ink composition. However, in order to evaluate the aggregation unevenness when printing secondary colors or more by the ink set, the printing is performed by determining the total amount of ink adhered to the recording medium of the five inks constituting the ink set. The amount of ink adhered to each ink was equalized and divided into five equal parts, assuming that the amount of ink adhered was the same as in the evaluation of uneven aggregation of objects. This was done using ink sets 1 and 2. The results are shown below.
Ink set No. Coagulation unevenness Ink set 1 4
Ink set 2 1

3.2.3. Evaluation Results The ink sets 1 and 2 provided with the orange ink composition containing the pigment orange 43 showed excellent weather resistance of the recorded material and had a large gamut volume. On the other hand, the ink sets 3 to 5 not provided with the orange ink composition containing the pigment orange 43 had poor weather resistance or a narrow gamut volume. Further, the ink set 1 in which each ink contains an ink containing the solvent of the solvent group A was also excellent in reducing secondary color aggregation unevenness, but the ink set 2 containing the solvent-free ink composition 17 of the solvent group A. Was inferior in reducing secondary color aggregation unevenness.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes substantially the same configurations as those described in the embodiments (eg, configurations with the same function, method and result, or configurations with the same purpose and effect). The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. Further, the present invention includes a configuration having the same action and effect as the configuration described in the embodiment or a configuration capable of achieving the same object. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (7)

At least one cyclic ester compound as a solvent, one or more compounds represented by the following general formula (2), and C.I. I. Pigment Orange-43 (PO-43) and resin,
The content of the cyclic ester is 10 to 30% by mass with respect to the total amount of the inkjet ink composition.
Based on the total amount of the content of the resin is the ink jet ink compositions, Ri 1 to 10% by mass,
A non-aqueous inkjet ink composition having a water content of 5% by mass or less based on the total amount of the inkjet ink composition.
R ¹ O- (R ² O) _m- R ³ ... (2)
[In the general formula (2), R ¹ and R ³ independently represent hydrogen or an alkyl group having 1 or more and 5 or less ^{carbon atoms, and R 2} represents an alkylene group having 2 or 3 carbon atoms. Represents an integer of 2-6. However, ^{at least one} of R 1 and R ³ is an alkyl group having 1 or more and 5 or less carbon atoms. ] In claim 1,
A non-aqueous inkjet ink composition in which the ratio of the total content of the resin to the total content of the cyclic ester is 0.1 to 1.0. In claim 1 or 2,
A non-aqueous inkjet ink composition in which the total content of the compound represented by the general formula (2) is 10% by mass or more and 90% by mass or less with respect to the total amount of the inkjet ink composition. In any one of claims 1 to 3,
A non-aqueous inkjet ink composition having a cyclic ester content of 10 to 20% by mass. The non-aqueous inkjet ink composition according to any one of claims 1 to 4, which is used for recording on a vinyl chloride-based recording medium. The non-aqueous inkjet ink composition according to any one of claims 1 to 5, a non-aqueous cyanide ink composition containing at least one cyclic ester compound as a solvent and a pigment, and a cyclic ester compound as a solvent. An ink set comprising at least a non-aqueous magenta inkjet ink composition containing at least one of a pigment and a non-aqueous yellow inkjet ink composition containing at least one of a cyclic ester compound as a solvent and a pigment. An inkjet recording method for recording on a recording medium by an inkjet method using the inkjet ink composition according to any one of claims 1 to 5 or the ink set according to claim 6.