JP7201022B2 - Non-aqueous inkjet ink composition - Google Patents

Description

The present invention relates to non-aqueous inkjet ink compositions.

2. Description of the Related Art Ink jet recording apparatuses are known that record images and characters by ejecting minute droplets of ink from nozzle holes of a recording head and adhering them to a recording medium. Ink jet ink compositions containing various components such as coloring materials, surfactants, water, and organic solvents are known as inks used for such recording. In the field of inkjet ink compositions, non-aqueous inkjet ink compositions that contain substantially no water have also been developed.

Such a non-aqueous ink composition has good adaptability to vinyl chloride-based recording media, and is often used for so-called signage recording such as outdoor signboards. However, when the non-aqueous inkjet ink composition is used for signage, the recorded matter may have insufficient weather resistance. That is, recorded materials for signage are often used in outdoor environments exposed to rain, sunlight, etc., and are required to have higher weather resistance than indoor use.

On the other hand, by using orange ink (special color ink) in addition to cyan, magenta, yellow, and black inks, it is possible to reproduce colors with a wide gamut. have been found to be inferior. Therefore, from the viewpoint of improving the weather resistance of orange ink, C.I. I. An aqueous ink composition, a non-aqueous ink composition, and an ink set containing Pigment Orange 43 (hereinafter also simply referred to as "PO43") as a pigment for orange ink have been proposed (see, for example, Patent Documents 1 to 3). .

JP 2009-173853 A Japanese Patent Application Laid-Open No. 2004-70048 JP 2011-89043 A

However, it has become clear that foreign substances are generated in the ink when the non-aqueous ink composition containing PO43 is stored for a long period of time. When foreign matter is generated in the ink, problems such as clogging of the ink ejection nozzles of the inkjet printer and the occurrence of missing nozzles may occur.

Therefore, some aspects of the present invention solve at least part of the above problems, thereby forming an image excellent in weather resistance and print quality, suppressing the generation of ink foreign matter, and enabling long-term storage. A non-aqueous inkjet ink composition having excellent stability is provided.

In addition to these, some aspects of the present invention provide a non-aqueous inkjet ink composition capable of forming an image having excellent abrasion resistance.

The present invention has been made to solve at least part of the problems described above, and can be implemented as the following aspects or application examples.

[Application example 1]
One aspect of the non-aqueous inkjet ink composition according to the present invention is
C.I. I. Pigment Orange 43,
one or more compounds represented by the following general formula (1) as a solvent;
including
The content of water contained in the ink composition is characterized by being 0.1% by mass or more and 2% by mass or less.
R ¹ O—(R ² O) _m —R ³ (1)
(In general formula (1), R ¹ and R ³ each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, provided that at least one of R ¹ and R ³ has 1 carbon atom an alkyl group of 4 or less, R ² represents an alkylene group having 2 or 3 carbon atoms, and m represents an integer of 2 to 3.)

According to the non-aqueous inkjet ink composition of Application Example 1, it is possible to form an image excellent in weather resistance and print quality, the generation of foreign substances in the ink is suppressed, and the composition is excellent in long-term storage stability.

[Application example 2]
In the non-aqueous inkjet ink composition of Application Example 1,
The content of the pigment contained in the ink composition may be 1% by mass or more and 6% by mass or less.

[Application Example 3]
In the non-aqueous inkjet ink composition of Application Example 1 or Application Example 2,
The total content of the compound represented by formula (1) contained in the ink composition may be 10% by mass or more and 90% by mass or less.

[Application example 4]
In the non-aqueous inkjet ink composition of any one of Application Examples 1 to 3,
A compound having a flash point of 70° C. or less among the compounds represented by the general formula (1) may be included, and the total content of the compounds contained in the ink composition may be 50% by mass or more.

[Application example 5]
In the non-aqueous inkjet ink composition of any one of Application Examples 1 to 4,
The ink composition may further contain one or more cyclic esters as the solvent, and the total content of the cyclic esters contained in the ink composition may be 5% by mass or more and 40% by mass or less.

[Application example 6]
In the non-aqueous inkjet ink composition of any one of Application Examples 1 to 5,
Furthermore, vinyl chloride resin can be included.

[Application example 7]
In the non-aqueous inkjet ink composition of any one of Application Examples 1 to 6,
A content of the water may be 0.1% by mass or more and 1% by mass or less.

Preferred embodiments of the present invention are described below. The embodiments described below describe examples of the present invention. The present invention is by no means limited to the following embodiments, and includes various modifications implemented within the scope of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

1. Non-aqueous inkjet ink composition The non-aqueous inkjet ink composition according to the present embodiment contains a solvent and a pigment, and the content of water contained in the ink composition is 0.1% by mass or more and 2% by mass or less. It is characterized by The non-aqueous inkjet ink composition according to the present embodiment contains a volatile solvent (mainly an organic solvent) as a main component, and after being deposited on a recording medium, the solvent is dried by heating or at room temperature to fix the solid content. This ink is used for recording by Therefore, the ink is different from photocurable ink that is cured by irradiation with radiation (light).

The term "non-aqueous" inkjet ink composition in the present invention means that water is not intentionally added during the production of the ink composition, and the ink composition is inevitably mixed during production or storage. It does not matter if it contains moisture.

Each component contained in the non-aqueous inkjet ink composition according to the present embodiment will be described below.

1.1. Solvent The non-aqueous inkjet ink composition according to the present embodiment contains one or more compounds represented by the following general formula (1) as a solvent.

1.1.1. Compounds represented by general formula (1) R ¹ O—(R ² O) _m —R ³ (1)
(In general formula (1), R ¹ and R ³ each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, provided that at least one of R ¹ and R ³ has 1 carbon atom an alkyl group of 4 or less, R ² represents an alkylene group having 2 or 3 carbon atoms, and m represents an integer of 2 to 3.)

Here, the alkyl group having 1 to 4 carbon atoms may be a linear or branched alkyl group, specifically, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group. , n-butyl group, sec-butyl group and tert-butyl group. Examples of the alkylene group having 2 or 3 carbon atoms include an ethylene group (dimethylethylene) and a propylene group (trimethylene or methylethylene). The compound represented by the general formula (1) may be contained singly or in combination of two or more.

Specific examples of the compound represented by the general formula (1) include diethylene glycol monomethyl ether (105° C.) (sometimes abbreviated as “DEGmME”), triethylene glycol monomethyl ether (139° C.), and diethylene glycol monoisopropyl. Ether (101°C), diethylene glycol monobutyl ether (120°C), triethylene glycol monobutyl ether (156°C), diethylene glycol monoisobutyl ether (112°C), dipropylene glycol monomethyl ether (76.5°C), tripropylene glycol monomethyl ether (123 ° C.), dipropylene glycol monopropyl ether (108 ° C.), dipropylene glycol monobutyl ether (117 ° C.), tripropylene glycol monobutyl ether (138 ° C.), diethylene glycol dimethyl ether (56 ° C.) (abbreviated as “DEGdME” ), triethylene glycol dimethyl ether (113°C) (sometimes abbreviated as “TriEGdME”), diethylene glycol methyl ethyl ether (64°C) (sometimes abbreviated as “DEGMEE”), diethylene glycol diethyl ether (70.8 ° C) (may be abbreviated as "DEGDEE"), diethylene glycol dibutyl ether (122 ° C) (may be abbreviated as "DEGdBE"), diethylene glycol butyl methyl ether (94 ° C) ("DEGBME ), dipropylene glycol dimethyl ether (65° C.), tripropylene glycol dimethyl ether, and the like. In addition, the numerical value in the parenthesis in the said illustration shows a flash point.

The above flash point shall be the flash point by the Cleveland open flash point tester if the flash point by the closed tag flash point tester is not 80 ° C or less, and the flash point by the closed tag flash point tester is 80 ° C or less. In the case of , if the dynamic viscosity of the solvent at the flash point is less than 10 cSt, the flash point is determined by a closed tag flash point tester, and if the dynamic viscosity of the solvent at the flash point is 10 cSt or more, the seta closed flash point test The flash point is determined by the instrument.

From the viewpoint of achieving both the drying property of the non-aqueous inkjet ink composition on a recording medium and the print image quality, among these compounds, it is preferable to include a compound having a flash point of 75° C. or less, more preferably 70° C. or less, and furthermore. It preferably contains a compound having a temperature of 50° C. or higher and 70° C. or lower, particularly preferably 55° C. or higher and 68° C. or lower. In addition, the content of the compound (compound having a flash point of 75 ° C. or less among the compounds represented by the general formula (1)) with respect to the total mass of the non-aqueous inkjet ink composition (when using multiple types, total amount) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% by mass or more. In addition, among the above compounds, the content of compounds having a flash point of 70° C. or less (the total amount when multiple types are used) is preferably 50% by mass or more, more preferably 60% by mass or more, Particularly preferably, it is 65% by mass or more. When the content of the compound contained in the ink composition is within the above range, the drying property of the non-aqueous inkjet ink composition can be improved, and wet spreading and uneven aggregation (aggregation of pigments, etc.) in the formed image can be improved. ) can be suppressed and the glossiness can be improved. In addition, the non-aqueous inkjet ink composition tends to have better storage stability than other solvents. The reason for this is presumed to be that, among the compounds represented by the general formula (1), compounds having a flash point of 75° C. or lower can suppress the increase in water content during long-term storage of the ink.

The content of the compound represented by the general formula (1) with respect to the total mass of the non-aqueous inkjet ink composition (the total amount when multiple types are used) 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.

1.1.2. Cyclic Ester The non-aqueous inkjet ink composition according to the present embodiment preferably contains a cyclic ester (cyclic lactone). By containing a cyclic ester, the non-aqueous inkjet ink composition dissolves a part of the recording surface of the recording medium (for example, the recording surface containing the vinyl chloride resin) to the inside of the recording medium. You can permeate things. By penetrating the ink into the inside of the recording medium in this way, it is possible to improve the abrasion resistance (rubbing fastness) of the image recorded on the recording medium. In other words, the cyclic ester has a high affinity with the vinyl chloride resin, so that the components of the non-aqueous inkjet ink composition can easily infiltrate (stick to) the recording surface. As a result of the cyclic ester having such an effect, it is believed that a non-aqueous inkjet ink composition containing the cyclic ester can form images with excellent abrasion resistance even under severe conditions such as outdoor environments.

A cyclic ester is one molecule having a hydroxyl group and a carboxyl group,
It is a compound having a structure in which the hydroxyl group and the carboxyl group are dehydrated and condensed in the molecule. Cyclic esters have a heterocyclic ring containing two or more carbon atoms and one oxygen atom, and have a structure in which a carbonyl group is arranged adjacent to the oxygen atom forming the heterocyclic ring, and are collectively referred to as lactones. It is a compound that

Examples of cyclic esters having simple structures 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 heterocyclic ring of the cyclic ester is not particularly limited, and any side chain may be bonded to the ring member of the heterocyclic ring, for example. Cyclic esters may be used singly or in combination of two or more.

From the viewpoint of further enhancing the abrasion resistance of an image formed by the non-aqueous inkjet ink composition according to the present embodiment, among the cyclic esters exemplified above, cyclic esters having a 3- to 7-membered ring are preferable. It is more preferable to use a cyclic ester with a membered ring or a 6-membered ring, in which case it is more preferable to have no side chains. Specific examples of such cyclic esters include γ-butyrolactone and σ-valerolactone. In addition, since such a cyclic ester has particularly high affinity with polyvinyl chloride, when it is adhered to a recording medium containing polyvinyl chloride, the effect of increasing abrasion resistance can be obtained very significantly. can.

When a cyclic ester is blended, the content relative to the total mass of the non-aqueous inkjet ink composition (the total amount when multiple types are used) is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass. It is more than mass % and below 30 mass %.

1.1.3. Other Solvents In the non-aqueous inkjet ink composition according to the present embodiment, the following compounds can be used as solvents in addition to the compound represented by the general formula (1) and the cyclic ester.

Examples of such solvents include alcohols (methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol, fluorinated alcohol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), carboxylic acid esters (methyl acetate , 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, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, trimethylolpropane, etc.).

Moreover, (polyhydric) alcohols may be contained as a solvent. (Polyhydric) alcohols include glycerin, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 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, 2-dimethyl-1,3-propanediol, 2-methylpentane-2,4-diol, and the like.

The total content of the (polyhydric) alcohols in the non-aqueous inkjet ink composition is effective in improving wet spreadability and permeability on the recording medium to reduce unevenness in density and storage stability. From the viewpoint of ensuring properties and 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, relative to the total mass of the non-aqueous inkjet ink composition. is more preferable. When the content of the (polyhydric) alcohol is within the above range, the wettability, permeability, and drying properties of the ink are improved, and an image with good print density (color development) may be obtained. . In addition, when the content of the (polyhydric) alcohol is within the above range, the viscosity of the ink can be made appropriate, and the occurrence of clogging of nozzles can be reduced in some cases.

In addition, the non-aqueous inkjet ink composition may contain amines, such as triethanolamine, tripropanolamine, tributanolamine, N,N-dimethyl-2-aminoethanol, N,N-diethyl- Examples include hydroxylamines such as 2-aminoethanol, and one or more 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, based on the total mass of the non-aqueous inkjet ink composition. % or less.

In addition, as solvents, higher fatty acid esters such as methyl laurate, isopropyl hexadecanoate (isopropyl palmitate), isopropyl myristate, methyl oleate and ethyl oleate, dicarboxylic acids of aliphatic hydrocarbons having 2 to 8 carbon atoms (carbon dibasic acid diesters that are diesterified with alkyl groups having 1 to 5 carbon atoms, and monocarboxylic acids of aliphatic hydrocarbons having 6 to 10 carbon atoms (the number of carbon atoms is excluding carbon atoms in the carboxyl group excluding carbon) (the substituents substituting the amide nitrogen atom are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) alkylamide (N,N-dimethyldecanamide, etc.) etc.

One or more of the other solvents exemplified here can be added in an appropriate amount to the non-aqueous inkjet ink composition.

1.2. Pigment The non-aqueous inkjet ink composition according to the present embodiment contains C.I. I. Contains Pigment Orange 43 (PO43).

PO43 is a pigment with CAS Registry Number 4424-06-0 and the chemical name is bisbenzimidazo[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. PO43 has a penorine structure and has been given the generic name "penorine orange". The hue of PO43 is bright reddish orange. "C.I." is an abbreviation for color index.

PO43 can also use commercial products, for example, Clariant "Hostaperm Orange", "PV Gast Orange GRL", DIC Corporation "Fasogen Super Orange 6200", Toyo Ink Co., Ltd. "Lionogen Orange GR- It is available as F.

When adding PO43 to the ink, it is desirable to prepare a pigment dispersion before adding it to the ink. The method for producing the pigment dispersion is not particularly limited, and examples thereof include a method of adding PO43, a medium and other arbitrary components and dispersing them with a high-speed disper or the like. Furthermore, if necessary, it may be dispersed by a bead mill, a roll mill, or the like. Filter filtration and centrifugal separation are then carried out in order to remove particles of a certain size or larger that may be contained in the finally obtained pigment dispersion. When performing filter filtration, if necessary, the pore size (mesh size) of the filter is appropriately selected so as to adjust the particle size of the particles contained in the pigment dispersion to a predetermined particle size. may However, filter filtration may be performed at the stage of preparing the pigment dispersion, but it may also be performed at the stage of preparing the ink, or may be performed at each stage of preparing the pigment dispersion and the ink.

The volume average particle size of PO43 contained in the non-aqueous inkjet ink composition according to the present embodiment is preferably 100 nm or more and 400 nm or less, more preferably 150 nm or more and 300 nm or less. Here, the volume average particle size of the pigment can be evaluated by a laser diffraction/scattering method. Specifically, an ink sample (pigment) is diluted with DEGdEE (diethylene glycol diethyl ether) to 1000 ppm or less, and this is measured by a laser diffraction/scattering measurement device (for example, Microtrac UPA250 (manufactured by Nikkiso Co., Ltd.) )) under an environment of 20° C. by reading the value of the median diameter D50. Therefore, even when PO43 having different volume average particle sizes are mixed and used, the volume average particle size of each and the volume average particle size of the mixture can be measured.

Even when PO43 having different volume average particle sizes are mixed and used, the volume average particle size of each PO43 is preferably 100 nm or more and 400 nm or less, the lower limit is more preferably 150 nm or more, and the upper limit is more preferably 350 nm. or less, more preferably 300 nm or less.

The non-aqueous inkjet ink composition according to the present embodiment contains, as a pigment, C.I. I. By including Pigment Orange 43 (PO43), it is possible to improve the overall balance of performance including weather resistance, print stability, and abrasion resistance.

If the volume average particle size of PO43 is within the above range, it can be used as it is, but the volume average particle size can be adjusted as follows. That is, after mixing the solvent (partially or entirely), the mixture (pigment dispersing solvent) is appropriately treated with a ball mill, bead mill, ultrasonic crushing and/or jet mill, etc. to obtain a particle size distribution and volume. Average particle size can be adjusted.

In addition, as a method for adjusting the volume average particle size of PO43, a pigment having a small primary particle size is prepared, and when this is mixed with a solvent (partially or entirely), the amount of a dispersant (described later) added is changed. can be employed to perform the dispersion. That is, if a sufficient amount of dispersant is added, agglomeration of primary particles can be prevented, and the particles can be dispersed with a particle size that is almost the same as that of the primary particles. By reducing the amount added, the primary particles can be aggregated to obtain a volume average particle size based on the particle size of the secondary particles. In this case, it is preferable to use a starting pigment having a smaller primary particle size, because this increases the degree of freedom in adjusting the volume average particle size. Furthermore, when it is desired to increase the degree of freedom in adjusting the volume average particle size, the obtained pigment is once pulverized with a ball mill or the like as described above to make it smaller, and then the average particle size is adjusted with a dispersant. may

The content of PO43 is preferably 1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 6% by mass or less, particularly preferably 1% by mass or more and 5% by mass or less. When the content of PO43 is within the above range, a distinctive orange ink with excellent color developability can be obtained. In addition, an image formed with this ink has good weather resistance.

On the other hand, the non-aqueous inkjet ink composition according to this embodiment may further contain a coloring material other than PO43 described above. Such colorants include pigments and dyes of hues similar to PO43, such as C.I. I. pigments numbered C.I.P.O. I. Examples include those given a Pigment Red number.

1.3. Water The non-aqueous inkjet ink composition according to the present embodiment contains 0.1% by mass or more and 2% by mass or less of water. When producing the non-aqueous inkjet ink composition according to the present embodiment, the solvent contains a trace amount of moisture, or the solvent absorbs moisture in the air during production, so that the non-aqueous inkjet ink composition about 3% by mass of water is often mixed. Therefore, in order to set the water content of the non-aqueous inkjet ink composition according to the present embodiment to 0.1% by mass or more and 2% by mass or less, each solvent used is dehydrated with a dehydrating agent. or by adding a recoverable dehydrating agent to the resulting non-aqueous inkjet ink composition to adjust the water content.

The chemical name of PO43 is bisbenzimidazo[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. The chemical structural formula of PO43 is as shown in formula (2) below. As shown in the following formula (2), PO43 has a chemical structure that does not have a hydrophilic group, so it is easily affected by water. Therefore, it is speculated that if the non-aqueous inkjet ink composition contains more than 2% by mass of water, the dispersion system of PO43 is destroyed and the PO43 aggregates with each other, resulting in an increase in particle size and an increase in viscosity. be done. As a result, problems such as clogging of nozzles for ejecting ink of an inkjet printer and the occurrence of missing nozzles may occur. On the other hand, in order to make the water content in the non-aqueous inkjet ink composition less than 0.1% by mass, not only does the dehydration process require a considerable amount of time, difficult to do

The water content of the non-aqueous inkjet ink composition according to the present embodiment is preferably 0.1% by mass or more and 1% by mass or less, more preferably 0.1% by mass, from the viewpoint of effectively suppressing aggregation of PO43. It is more than mass % and below 0.7 mass %.

The water content of the non-aqueous inkjet ink composition according to this embodiment can be measured by quantifying the produced non-aqueous inkjet ink composition with a Karl Fischer moisture meter. As such a device, for example, a trace moisture measuring device “AQ-2200” manufactured by Hiranuma Sangyo Co., Ltd., a Karl Fischer moisture meter “MKV-710S” manufactured by Kyoto Electronics Industry Co., Ltd., etc. can be used.

1.4. Other Components The non-aqueous inkjet ink composition according to the present embodiment may further contain components described below, such as vinyl chloride resins, acrylic resins, surfactants, and dispersants.

1.4.1. Vinyl chloride resin Vinyl chloride resin that can be used in the non-aqueous inkjet ink composition according to the present embodiment includes copolymers containing structural units derived from vinyl chloride and vinyl acetate (hereinafter referred to as "vinyl chloride copolymer Also referred to as "coalescence".) can be mentioned. The vinyl chloride acetate copolymer can be dissolved in the compound represented by the general formula (1). As a result, the vinyl chloride-acetate copolymer dissolved in the compound represented by the general formula (1) enables the ink to be firmly fixed on the surface of the recording medium containing the vinyl chloride-based resin.

A vinyl chloride acetate copolymer can be obtained by a conventional method, for example, by suspension polymerization. Specifically, water, a dispersant, and a polymerization initiator are charged into a polymerization vessel, and after deaeration, vinyl chloride and vinyl acetate are injected to carry out suspension polymerization, or part of vinyl chloride and vinyl acetate are injected. to start the reaction, and the suspension polymerization can be carried out while the remaining vinyl chloride is injected into the reaction.

The vinyl chloride/acetate copolymer preferably contains 70 to 90% by mass of vinyl chloride units as its constitution. If it is in the above range, it is stably dissolved in the inkjet ink composition, so that it is excellent in long-term storage stability. Furthermore, it is possible to obtain excellent ejection stability and excellent fixability to a recording medium.

In addition to the vinyl chloride units and vinyl acetate units, the vinyl chloride/vinyl acetate copolymer may optionally have other structural units such as carboxylic acid units, vinyl alcohol units, and hydroxyalkyl acrylate units. and vinyl alcohol units are particularly preferred. It can be obtained by using a monomer corresponding to each unit described above. Specific examples of monomers that provide carboxylic acid units include maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, acrylic acid, and methacrylic acid. Specific examples of monomers that give hydroxyalkyl acrylate units include hydroxyethyl (meth)acrylate and hydroxyethyl vinyl ether. The content of these monomers is not limited as long as it does not impair the effects of the present invention.

Moreover, a commercially available vinyl chloride acetate copolymer may be used, and examples thereof include Solbin CN, Solbin CNL, Solbin C5R, Solbin TA5R, Solbin CL (manufactured by Nissin Chemical Industry Co., Ltd.) and the like. .

Although the average degree of polymerization of the vinyl chloride resin is not particularly limited, it is preferably 150-1100, more preferably 200-750. When the average degree of polymerization of the vinyl chloride-based resin is within the above range, it is stably dissolved in the non-aqueous inkjet ink composition according to the present embodiment, and thus has excellent long-term storage stability. Furthermore, it is possible to obtain excellent ejection stability and 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 "JIS K6720-2".

Although the number average molecular weight of the vinyl chloride resin is not particularly limited, it is preferably 10,000 to 50,000, more preferably 12,000 to 42,000. 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 non-aqueous inkjet ink composition according to the present embodiment is, for example, 0.05% by mass or more and 6% by mass or less, preferably 0.5% by mass or more and 4% by mass or less. can. When the content of the vinyl chloride resin is within the above range, the vinyl chloride resin dissolved in the compound represented by the general formula (1) provides excellent fixability to the vinyl chloride recording medium. . As the vinyl chloride-based resin, other than the vinyl chloride-acetate copolymer described above, any resin containing at least structural units derived from vinyl chloride can be used.

In the non-aqueous inkjet ink composition according to the present embodiment, the vinyl chloride resin and the compound represented by the general formula (1) are contained at a mass ratio of 1:5 to 1:40. is preferred. If the ratio is within the above range, the vinyl chloride resin can be easily dissolved in the compound represented by the general formula (1). Ink fixability can be improved, and clogging of nozzles is less likely to occur.

1.4.2. Acrylic Resin In addition to the vinyl chloride resin, an acrylic resin may be added to the non-aqueous inkjet ink composition according to the present embodiment from the viewpoint of improving the adhesion of the ink coating film of the image.

Examples of acrylic resins include poly(meth)acrylic acid, polymethyl(meth)acrylate, polyethyl(meth)acrylate, (meth)acrylic acid-(meth)acrylate copolymer resin, styrene-( meth)acrylic copolymer resin, ethylene-(meth)acrylic acid copolymer resin, ethylene alkyl(meth)acrylate resin, ethylene-(meth)acrylic acid ester copolymer resin and the like.

As the above acrylic resin, a commercially available product may be used. For example, ACRYPET MF (trade name, manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin), Sumipex LG (trade name, manufactured by Sumitomo Chemical Co., Ltd., acrylic resin), Paraloid B series (trade name, manufactured by Rohm and Haas Co., acrylic resin), Parapet G-1000P (trade name, manufactured by Kuraray Co., acrylic resin), and the like. In the present invention, (meth)acrylic acid means both acrylic acid and methacrylic acid, and (meth)acrylate means both acrylate and methacrylate.

The content of the acrylic resin in the non-aqueous inkjet ink composition according to the present embodiment can be, for example, 0.5% by mass or more and 10% by mass or less, preferably 0.5% by mass or more and 6% by mass or less. . When the content of the acrylic resin is within the above range, excellent fixability to a vinyl chloride recording medium can be obtained.

1.4.3. Surfactant In addition to the organic solvent, the non-aqueous inkjet ink composition according to the present embodiment contains a silicone surfactant, a fluorine-based surfactant, and Activators or polyoxyethylene derivatives that are nonionic surfactants may be added.

Polyester-modified silicone or polyether-modified silicone is preferably used as the silicone-based surfactant. Specific examples include BYK-347, 348, BYK-UV3500, 3510, 3530, and 3570 (all manufactured by BYK-Chemie Japan).

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

Moreover, as a polyoxyethylene derivative, it is preferable to use an acetylene glycol surfactant. Specific examples include Surfynol 82, 104, 465, 485, TG (all manufactured by Air Products Japan), Olfin STG, E1010 (all manufactured by Nissin Chemical Co., Ltd.), Nissan Nonion A-10R, A-13R. (both manufactured by NOF Corporation), Floren TG-740W, D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Neugen CX-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

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

1.4.4. Dispersant The non-aqueous inkjet ink composition according to the present embodiment can use any dispersant that is used in ordinary ink compositions 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 Chemicals Co., Ltd.). Compounds, Solsperse 20000, 24000, 32000, 32500, 33500, 34000, 35200, 37500 (all manufactured by LUBRIZOL "Solsperse"), Disperbyk-161, 162, 163, 164, 166, 180, 190, 191, 192 (all BYK Chemie Japan), Floren DOPA-17, 22, 33, G-700 (both manufactured by Kyoeisha Chemical Co., Ltd.), Ajisper PB821, PB711 (both manufactured by Ajinomoto Co., Inc.), LP4010, LP4050, LP4055, POLYMER400, 401, 402, 403, 450, 451, 453 (all manufactured by EFKA Chemicals) and the like.

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, imino group or pyrrolidone group as a basic group are preferred. 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 as polymeric dispersants having basic groups.

Specific examples of polymeric dispersants having a basic group include BYK Chemie's "Anti-Terra-U (polyaminoamide phosphate)", "Anti-Terra-204 (high molecular weight polycarboxylate)", "Disperbyk-101 (polyaminoamide phosphate and acid ester) 130 (polyamide) can be mentioned. Also, Avecia's Solsperse 5000 (phthalocyanine ammonium salt system), 13940 (polyester polyimine), 17000, 18000, Examples include 19000 (polyester polyamine) and 11200 (polyester polyimine), and V-216 and V-220 (polyvinylpyrrolidone having a long-chain alkyl group) manufactured by ISP.

In the ink composition according to the present embodiment, when the dispersant is used, the content thereof can be appropriately selected according to the pigment contained. On the other hand, it is preferably 5 parts by mass or more and 200 parts by mass or less, more preferably 30 parts by mass or more and 120 parts by mass or less.

1.4.5. Others In addition to the above components, the non-aqueous inkjet ink composition according to the present embodiment contains resins other than vinyl chloride resins and acrylic resins, chelating agents such as ethylenediaminetetraacetate (EDTA), and preservatives.・Substances for imparting predetermined performance, such as antifungal agents and anticorrosive agents, can be contained.

Examples of resins other than vinyl chloride resins and acrylic resins include aliphatic polyesters, aromatic polyesters, polyurethanes, epoxy resins, polyvinyl acetates, ethylene-vinyl acetate copolymer resins, polycarbonates, polyvinyl butyral, polyvinyl alcohols, and phenoxy resins. , ethyl cellulose resin, cellulose acetate propionate resin, cellulose acetate butyrate, nitrocellulose resin, polystyrene, vinyl toluene-α-methylstyrene copolymer resin, polyamide, polyimide, polysulfone resin, petroleum resin, chlorinated polypropylene, polyolefin , terpene-based resins, rosin-modified phenolic resins, various synthetic rubbers such as NBR, SBR, MBR, and modified products thereof. These resins may be used singly or in combination of two or more.

1.5. Uses and Effects The non-aqueous inkjet ink composition according to the present embodiment is a non-aqueous ink composition containing the compound represented by the general formula (1), so that recording can be performed on film media such as vinyl chloride-based recording media. Since the image quality is excellent when the image is displayed, it is particularly suitable for sign applications displayed outdoors. The vinyl chloride-based recording medium is not particularly limited as long as it contains a vinyl chloride-based resin. Recording media containing vinyl chloride resins include hard or soft vinyl chloride films or sheets. The non-aqueous inkjet ink composition according to the present embodiment enables recording of an image on the untreated surface of a vinyl chloride resin substrate, and is expensive for recording as with conventional recording media having a receiving layer. It has an excellent effect of not requiring the use of a medium, and needless to say, it can be applied even to substrates surface-treated with an ink-receiving layer.

The non-aqueous inkjet ink composition according to the present embodiment has a water content of 0.1% by mass or more and 2% by mass or less, thereby suppressing the aggregation (foreign matter) of PO43 due to long-term storage and stabilizing storage. good properties. As a result, clogging of the nozzles of the inkjet printer can be prevented, and ejection reliability can be improved.

In addition, when the non-aqueous inkjet ink composition according to the present embodiment contains PO-43, when it is applied to signage to be displayed outdoors, weather resistance of the image is particularly good. Further, the abrasion resistance can be improved by adding a cyclic ester, but the cyclic ester tends to have high hygroscopicity, and the dispersion stability of PO43 tends to be impaired. However, by using a compound represented by the above general formula (1) with a flash point of 75° C. or less and a cyclic ester in combination, it is possible to ensure the abrasion resistance of the image and further improve the storage stability. This is a particularly preferred embodiment.

Further, by making an ink set in which each color ink such as cyan, magenta, yellow, and black is combined with a special color orange ink (the ink composition according to the present embodiment), color reproduction with a wide gamut becomes possible. The color reproduction is maintained over a long period of time.

2. Examples and Comparative Examples Examples and Comparative Examples are shown below to further describe the present invention, but the present invention is not limited to the following examples. "Parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

2.1. Preparation of ink composition 2.1.1. Production of Pigment 120 mL of ion-exchanged water, 18 g of hydrochloric acid, 6.8 g of acetic acid, and 2 g of polyoxyalkylenealkylamine were put into a 500 mL container, mixed and stirred. Next, after adding 16 g of 2,5-dichloroaniline, add ice to adjust the liquid temperature to about 5°C, add 6 g of sodium nitrite, and keep the liquid temperature in the container at 10°C or less. , and stirred for 30 minutes to obtain a diazotized solution.

On the other hand, 200 mL of ion-exchanged water and 23.5 g of 2-acetoacetylamino-6-ethoxybenzothiazole were put into a 300 mL container and stirred for 30 minutes. After that, 5.2 g of potassium hydroxide was added and stirred for 30 minutes to obtain a reaction liquid.

The diazotized liquid obtained above was filtered with a filter paper (No. 5C), and the filtrate was put into a 2 L container. After adding 1 g of sulfamic acid and 15 g of sodium acetate to the filtrate, the liquid temperature was adjusted to 25° C. and the pH was adjusted to 2.0 to 3.0. While maintaining the liquid temperature at 25° C., the above reaction liquid was added and stirred for 60 minutes. Next, after raising the liquid temperature to 90° C. and stirring for 30 minutes, a 30% sodium hydroxide aqueous solution was added to adjust the pH to 8.5. The finally obtained reaction solution was filtered, and the residue was washed with ion-exchanged water and dried at 80°C. The dried residue was pulverized with a sample mill to obtain a powdery pigment (crude material).

The crude material thus obtained was dried by heating at 105°C. After adding 50 g of this crude material to 450 mL of N-methyl-2-pyrrolidone (NMP), the temperature was raised to 80° C. with stirring (heating time is about 1 hour), and the mixture was stirred at 80° C. for 2 hours. bottom. After that, it was cooled to 30° C. or less, and then filtered with Nutsche. The filter-separated residue was washed with 2 L of ion-exchanged water, and the filter-separated residue was obtained as a paste-like pigment dispersion containing the pigment and ion-exchanged water. After that, the product was dried by heating at 105° C. and pulverized with a sample mill to obtain powdery PO43.

2.1.2. Preparation of Pigment Dispersion Using the pigment obtained above and Solsperse 37500 (manufactured by Lubrizol) as a dispersant, the amount of the dispersant added is varied within the range of 100 to 400 parts by mass with respect to 100 parts by mass of the pigment. to prepare a dispersion liquid. As the dispersion medium, the solvent having the largest content as the solvent for each ink composition example was used as the dispersion medium to prepare the pigment dispersion liquid.

2.1.3. Preparation of Ink Composition Using the pigment dispersion liquid prepared above, ink compositions with different pigment types and solvent types were prepared with the material compositions shown in Tables 1 and 2. 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 through a membrane filter with a pore size of 5 μm to remove impurities such as dust and coarse particles. Prepared by The numerical values in the composition columns in Tables 1 and 2 indicate % by mass.

Further, among the ink compositions of Examples and Comparative Examples, those having a water content of 2% by mass or less were subjected to a step of dehydrating each solvent using a dehydrating agent. For the ink compositions containing 3% or more water as in Comparative Examples 5 and 6, the commercially available solvent was used as it was without performing the dehydration step, and ion-exchanged water was added to adjust the water content. bottom. The ink composition containing 0.1% by mass of water in Example 8 was obtained by dehydrating each solvent using a dehydrating agent, but dehydration took a considerable amount of time.

For each ink composition thus obtained immediately after preparation, the water content was measured using a Karl Fischer moisture meter (Hiranuma Sangyo Co., Ltd., model "AQ-2200"). The results are also shown in Tables 1 and 2.

2.2. Evaluation test 2.2.1. Evaluation of weather resistance Using an inkjet printer (manufactured by Seiko Epson Corporation, model "SC-S70650"), each ink composition of Examples and Comparative Examples was applied to a vinyl chloride banner sheet (manufactured by 3M, model number IJ51 (polyvinyl chloride )), solid printing was performed at a recording resolution of 720×720 dpi to obtain a recorded matter. The obtained recorded matter is put into the chamber of a xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), and the conditions are “light irradiation for 40 minutes” → “light irradiation + water rain for 20 minutes” → “light irradiation for 60 minutes” → “water A cycle test of 60 minutes of rainfall was performed. The operating conditions for the xenon weather meter are as follows. This cycle test was performed continuously for 4 weeks, and the recordings were taken out after 4 weeks. The OD value of each recorded material taken out was measured using a Gretag densitometer (manufactured by Gretag Macbeth) to obtain the OD value retention rate (%), which was judged based on the following criteria.
<Judgment Criteria>
○: OD value residual rate is 90% or more.
Δ: OD value residual rate is 81% or more and less than 90%.
x: OD value residual rate is less than 81%.
<Conditions for xenon weather meter>
Temperature and humidity: 40°C 50% RH
Irradiation intensity: 300-400 nm, 60 W/m ²

2.2.2. Evaluation of print image quality (1) Evaluation of aggregation unevenness Using an inkjet printer (manufactured by Seiko Epson Corporation, model "SC-S70650"), each ink composition of Examples and Comparative Examples was applied to a polyvinyl chloride banner sheet (manufactured by 3M, 100% density and solid printing with a recording resolution of 720×720 dpi were performed on model number IJ51 (polyvinyl chloride)) and dried for 60 minutes in an environment of 25° C. and 65% RH (relative humidity). Thereafter, the evaluation sample was returned to room temperature (25° C.), and the uneven aggregation of the pigment on the recording surface of the evaluation sample was visually observed to evaluate the uneven aggregation. Judgment criteria are as follows.
<Judgment Criteria>
◯: Aggregation unevenness is not observed.
Δ: Slight aggregation unevenness is observed.
x: Aggregation unevenness is conspicuous.

(2) Evaluation of Glossiness For the evaluation sample obtained in the above <Evaluation of uneven aggregation>, the glossiness of the 20° reflection of the recording surface was measured using a photometer MULTI Gloss 268 (manufactured by Konica Minolta). . Judgment criteria are as follows.
<Judgment Criteria>
○: 50 or more.
(triangle|delta): 30-50.
x: less than 30.

(3) Evaluation of Print Image Quality The print image quality was evaluated by comprehensively judging from the evaluation of aggregation unevenness and glossiness. Judgment criteria are as follows.
<Judgment Criteria>
◯: Both the evaluation of uneven aggregation and the evaluation of glossiness are ◯.
Δ: There is no x in the evaluation of aggregation unevenness and the evaluation of glossiness, and either is Δ.
x: Either the evaluation of aggregation unevenness or the evaluation of glossiness is x.

2.2.3. Evaluation of abrasion resistance Using an inkjet printer (manufactured by Seiko Epson Corporation, model "SC-S70650"), each ink composition of Examples and Comparative Examples was applied to a polyvinyl chloride banner sheet (manufactured by 3M, model number IJ51 (polyvinyl chloride )) was printed solid with a recording resolution of 720×720 dpi at a density of 100% and dried for 60 minutes in an environment of 25° C. and 65% RH (relative humidity). After that, after returning this evaluation sample to room temperature (25 ° C.), in accordance with JIS K5701 (ISO 11628), a Gakushin rubbing fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301"). was used to evaluate the abrasion resistance. Specifically, a cotton cloth was placed on the recording surface of the evaluation sample, and rubbed by reciprocating a load of 500 g 20 times. Judgment criteria are as follows.
<Judgment Criteria>
◯: There is no dirt on the cotton cloth. No scratches on the recording surface.
Δ: Printed matter adheres to cotton cloth. There are almost no scratches on the recording surface.
x: Printed matter adheres to the cotton cloth. The recording surface is scratched.

2.2.4. Evaluation of Storage Stability 700 mL of each ink composition of Examples and Comparative Examples was filled in an ink pack composed of a polypropylene film (thickness: 100 μm), sealed, and left at 70° C. for 1 week. The range of variation in physical properties (viscosity and volume average particle size) was measured. Even if the ink composition is sealed with a polypropylene film, water may pass through the film and the water content in the ink composition may slightly increase.
The volume average particle size was measured by diluting the ink sample with diethylene glycol diethyl ether to 1000 ppm, and using a laser diffraction/scattering measurement device (manufactured by Nikkiso Co., Ltd., device name “Microtrac UPA250”) in an environment of 20 ° C. It was measured by reading the volume average particle size (median size D50) below.
The viscosity was measured using a viscometer (manufactured by Anton Paar, device name: "MCR300") at 20°C and a shear rate of 200/s.
Criteria for storage stability are as follows.
<Judgment Criteria>
⊚: less than 2%, whichever is greater in variation of viscosity or volume average particle size.
◯: 2% or more and less than 6%, whichever is larger in variation range of viscosity or volume average particle size.
Δ: 6% or more and less than 11%, whichever is larger in variation range of viscosity or volume average particle size.
x: 11% or more, whichever has a larger fluctuation range of viscosity or volume average particle size.

2.3. Evaluation Results Tables 1 and 2 show ink compositions and evaluation results for Examples and Comparative Examples.

The abbreviations or product names shown in Tables 1 and 2 are as follows.
<Pigment>
- PO43: C.I. I. pigment orange 43
- PO64: C.I. I. pigment orange 64
<Cyclic ester>
・γ-butyrolactone: trade name, manufactured by Kanto Kagaku Co., Ltd.)
・ σ-valerolactone: trade name, manufactured by Kishida Chemical Co., Ltd.)
<Solvent>
・ DEGMEE: Diethylene glycol methyl ethyl ether, trade name “Hi-solve 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 butyl methyl ether, trade name “Hi-solve BD
M", manufactured by Toho Chemical Industry Co., Ltd., flash point 94 ° 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 “Butysenol 40”, manufactured by KH Neochem Co., Ltd., flash point 177 ° C.)
Equamid M100: trade name, manufactured by Idemitsu Kosan Co., Ltd., amide solvent <dispersant>
Solsperse 37500: trade name, manufactured by Lubrizol, polyester polyamide resin <surfactant>
・BYK340: Product name, manufactured by BYK-Chemie Japan Co., Ltd., silicon-based surfactant <fixing resin>
・ Solbin CL: trade name, manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride-vinyl acetate copolymer

According to Examples 1 to 10, it was found that by using the non-aqueous inkjet ink composition of the present invention, images having excellent weather resistance and print quality can be formed. In addition, it was found that the non-aqueous inkjet ink composition of the present invention has an effect of suppressing aggregation of PO43 and is excellent in storage stability.

In Examples 1 to 3, it was found that containing 50% by mass or more of the low-flash-point glycol ether resulted in extremely excellent storage stability. On the other hand, in Examples 4 to 6, it was found that the storage stability was slightly reduced compared to Examples 1 to 3 by containing glycol ether with a slightly higher flash point or by increasing the amount of water. . In Example 7, since it does not contain a cyclic ester that easily absorbs moisture, the storage stability is very excellent. I didn't. In Example 8, the water content in the ink was extremely small, so the storage stability was excellent, but the solvent dehydration process required a considerable amount of time, resulting in poor productivity. In Example 9, since the content of PO43 was small, the occurrence of aggregation between PO43 particles was reduced, and the storage stability was very excellent. In Example 10, since the water content in the ink was small, the storage stability was very excellent. With such a water content, the dehydration step of the solvent did not take much time and the productivity was good. .

In Comparative Examples 1 and 6, since PO64 was used, the weather resistance of the images was poor. In Comparative Examples 2 to 4, since the specific glycol ether was not contained, both storage stability and print quality were poor. In Comparative Example 5, since PO43 was contained and water content was 3% by mass, aggregation of PO43 occurred and the storage stability was deteriorated. In addition, in Comparative Example 6, the storage stability was good despite the water content of 4% by mass. rice field.

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same function, method, and result, or configurations that have the same purpose and effect). Moreover, the present invention includes configurations in which non-essential portions of the configurations described in the embodiments are replaced. In addition, the present invention includes a configuration that achieves the same effects or achieves the same purpose as the configurations described in the embodiments. In addition, the present invention includes configurations obtained by adding known techniques to the configurations described in the embodiments.

Claims (7)

C.I. I. Pigment Orange 43,
As a solvent, one or more compounds represented by the following general formula (1) and one or more cyclic esters ;
including
containing diethylene glycol diethyl ether as the compound represented by the general formula (1),
The content of the diethylene glycol diethyl ether is 40% by mass or more with respect to the total mass of the ink composition,
A non-aqueous inkjet ink composition, wherein the content of water contained in the ink composition is 0.1% by mass or more and 2% by mass or less.
R ¹ O—(R ² O) _m —R ³ (1)
(In general formula (1), R ¹ and R ³ each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, provided that at least one of R ¹ and R ³ has 1 carbon atom an alkyl group of 4 or less, R ² represents an alkylene group having 2 or 3 carbon atoms, and m represents an integer of 2 to 3.) The non-aqueous inkjet ink composition according to claim 1, wherein the content of the pigment contained in the ink composition is 1% by mass or more and 6% by mass or less. The non-aqueous inkjet ink composition according to claim 1 or 2, wherein the total content of the compound represented by the general formula (1) contained in the ink composition is 40 % by mass or more and 90% by mass or less. thing. 1 . wherein the ink composition contains a compound having a flash point of 70° C. or less among the compounds represented by the general formula (1), and the total content of the compound contained in the ink composition is 50% by mass or more. 4. The non-aqueous inkjet ink composition according to any one of items 3. The non-aqueous inkjet ink composition according to any one of claims 1 to 4, wherein the total content of the cyclic ester contained in the ink composition is 5% by mass or more and 40% by mass or less. 6. The non-aqueous inkjet ink composition according to any one of claims 1 to 5, further comprising a vinyl chloride resin. The non-aqueous inkjet ink composition according to any one of claims 1 to 6, wherein the water content is 0.1% by mass or more and 1% by mass or less.