JP2020063341A - Inkjet ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-moisture ink having excellent pigment dispersion stability and less curl.
The inkjet ink composition of the present invention comprises a pigment, water, triethylene glycol, 2-pyrrolidone, triethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, or diethylene glycol monobutyl ether acetate. The content of water is less than the content of triethylene glycol.
[Selection diagram] None

Description

  The present invention relates to inkjet ink compositions.

  The ink jet recording method is a method in which droplets of an ink composition are ejected from fine ejection nozzles to be ejected and adhered to a recording medium such as paper for printing. This method has a feature that a high-resolution and high-quality image can be printed at high speed with a relatively inexpensive device. In the inkjet ink composition used in such an inkjet recording method, various coloring materials and solvents are used depending on the recording medium used.

  For office use, there is an increasing need for a system capable of high-speed full-color printing without being restricted by recording media (for example, plain paper, coated paper, art paper, double-sided plain paper, etc.). Various studies have also been conducted on the composition of the inkjet ink composition in order to achieve high speed. For example, Patent Document 1 discloses an inkjet ink having a water content of less than 45% by mass in order to suppress curl and strike-through during printing on plain paper.

Japanese Patent Laid-Open No. 2005-220296

  However, the composition described in Patent Document 1 has a problem that it is not easy to ensure the dispersibility of the pigment when the content of water is 30% by mass or less. This is because the pigment used in the inkjet ink composition for office has the property of being easily compatible with paper for the purpose of improving the printing density. Since cellulose, which is the main component of paper, has an OH group, which is a hydrophilic group, in the molecule, the pigment used in the ink composition for office tends to have high hydrophilicity. It is not easy to ensure the dispersibility of the pigment as the composition is low and the content of the organic solvent is high.

  On the other hand, when the content of water in the ink composition is increased in order to ensure the dispersibility of the pigment, there is a problem that curling is likely to occur during printing. The curl occurs when water contained in the ink composition penetrates into the recording medium and swells, and then the water evaporates to reduce the swelling. That is, there has been a demand for an inkjet ink composition that suppresses curling and improves the dispersion stability of the pigment.

  The inkjet ink composition of the present application contains a pigment, water, triethylene glycol, 2-pyrrolidone, triethylene glycol monobutyl ether, and diethylene glycol monoethyl ether acetate, or diethylene glycol monobutyl ether acetate. However, the content of water is less than the content of triethylene glycol with respect to the total mass of the inkjet ink composition.

  In the above inkjet ink composition, the content of water is preferably 40% by mass or less based on the total mass of the inkjet ink composition.

  It is preferable that the total content of diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate is less than 15% by mass based on the total mass of the inkjet ink composition.

  It is preferable that the content of triethylene glycol is equal to or more than the content of 2-pyrrolidone with respect to the total mass of the inkjet ink composition.

  The ink jet ink composition ejects minute ink droplets (droplets of the ink jet ink composition) from a jet nozzle of an ink jet head onto a recording medium such as plain paper by an ink jet method to produce images, colors, characters and patterns. Is used for forming

  The inkjet ink composition according to the present embodiment includes a pigment, water, triethylene glycol, 2-pyrrolidone, triethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, or diethylene glycol monobutyl ether acetate. , And the content of water is less than the content of triethylene glycol based on the total mass of the inkjet ink composition. Hereinafter, each component contained in the inkjet ink composition according to this embodiment will be described. In addition, in the following description, the inkjet ink composition is also simply referred to as an ink composition.

[Ink composition]
<Pigment>
As the inorganic pigment, carbon black (CI (Colour Index Generic Name) pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide and titanium oxide can be used.

  Examples of organic pigments include insoluble azo pigments, condensed azo pigments, azo pigments such as azo lake and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Polycyclic pigments, dye chelates (eg basic dye chelates, acid dye chelates, etc.), dye lakes (basic dye lakes, acid dye lakes), nitro pigments, nitroso pigments, aniline black, daylight Examples include fluorescent pigments.

  More specifically, as carbon black used as the black ink, No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 52. 2200B, etc. (manufactured by Mitsubishi Chemical Co., Ltd.), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc., manufactured by Columbia Carbon Co., Ltd., Rega1 400R, Rega1 330R, Rega1 660L, Mogul. 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (manufactured by Cabot Corp.), Color Black FW, Color Black FW2, Color Black FW2, Color Black FW2, Color Black FW2, Color Black FW2, Color Black FW2, Color Black Fluor Black, Color Black FW2, Color Black Fluor Black, Color Black FW2, Color Black Fluor Black, Color Black Black, Black Fluor Black, Color Black Fluor Black, Color Black Fluor Black, Color Black Black Fluor Black, Color Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Blue, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black Fluor Black, Color Black Black, Black Fluor Black. B1a ck S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4, Special Black 4, Special Black 4 and so on.

  Examples of pigments used in white ink include C.I. I. Pigment White 6,18,21.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1,2,3,4,5,6,7,10,11,12,13,14,16,17,24,34,35,37,53,55,65,73,74,75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154. 155,167,172,180.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1,2,3,4,5,6,7,8,9,10,11,12,14,15,16,17,18,19,21,22,23,30,31,32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 , 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, C.I. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

  Examples of pigments used in cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Butt Blue 4,60 can be mentioned.

  Examples of pigments other than magenta, cyan, and yellow include C.I. I. Pigment Green 7,10, C.I. I. Pigment Brown 3, 5, 25, 26, C.I. I. Pigment Orange 1, 2, 5, 7, 13, 14, 15, 15, 24, 34, 36, 38, 40, 43, 63.

  The content of the pigment is not particularly limited, but is preferably 0.1% by mass or more and 30% by mass or less based on the total mass of the ink composition. It is more preferably 1% by mass or more and 20% by mass or less, and further preferably 1% by mass or more and 15% by mass or less. By setting the content of the pigment within the above range, it is possible to secure the coloring of the pigment in the medium recorded by inkjet, and to suppress the increase in the viscosity of the ink composition and the occurrence of clogging of the inkjet head.

  In order to improve the dispersibility of the pigment in the ink composition, it is preferable to subject the pigment to a surface treatment or to add a dispersant or the like. The surface treatment of the pigment is a method of introducing a hydrophilic group such as a carboxy group or a sulfo group onto the particle surface of the pigment by physical treatment or chemical treatment. Surface treatment of the pigment allows the pigment to be dispersed in an aqueous solvent.

  In the dispersant, the hydrophobic part (hydrophobic group) in the molecular structure is adsorbed on the particle surface of the pigment, and the hydrophilic part (hydrophilic group) is oriented to the solvent side (medium side). This action allows the pigment to be dispersed in an aqueous solvent. As the dispersant, a known surfactant or resin can be used. Alternatively, a method of coating the pigment particles with a resin or the like to impart dispersibility may be used. As a method for coating the pigment particles, an acid precipitation method, a phase inversion emulsification method, a miniemulsion polymerization method and the like can be adopted.

  <Water>

* CL2 Support Water is the solvent with the lowest viscosity and highest pigment dispersibility among the media of this embodiment. Therefore, it is mixed for the purpose of lowering the viscosity of the inkjet ink composition and improving the dispersibility of the pigment. However, the content of water is 40% by mass with respect to the total mass of the inkjet ink composition, since the curl of the recording medium becomes large when the content of the medium is the best among the media of the exemplary embodiment and the content is large. The following is preferable. It is more preferably 30% by mass or less.

  Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, and ultrapure water in which ionic impurities have been removed as much as possible. Further, by using water sterilized by irradiation of ultraviolet rays or addition of hydrogen peroxide, it is possible to prevent the generation of mold and bacteria when the aggregated liquid is stored for a long period of time. This tends to improve storage stability.

<Triethylene glycol>
Triethylene glycol has two OH groups in the molecule and thus has good pigment dispersibility, but has a high viscosity (50 mPa · s), and therefore it has a high viscosity (50 mPa · s). , 2-pyrrolidone, triethylene glycol monobutyl ether, and either diethylene glycol monoethyl ether acetate or diethylene glycol monobutyl ether acetate are preferably combined.

<2-pyrrolidone>
Since 2-pyrrolidone has an NH group which is a hydrophilic group, it has an advantage that the pigment dispersibility is relatively good and the viscosity is relatively low (17.2 mPa · s). On the other hand, since the curl is larger than that of triethylene glycol, the content of triethylene glycol is preferably equal to or more than the content of 2-pyrrolidone.

<Triethylene glycol monobutyl ether>
Triethylene glycol monobutyl ether has the advantages of relatively low viscosity (10.1 mPa · s) and almost no PP attack in the medium of the present embodiment, but when the content is high, the pigment dispersibility is high. Therefore, the content is preferably smaller than the content of triethylene glycol.

<Diethylene glycol monoethyl ether acetate or diethylene glycol monobutyl ether acetate>
Diethylene glycol monoethyl ether acetate (hereinafter sometimes simply referred to as “EDGAC”) or diethylene glycol monobutyl ether acetate (hereinafter sometimes simply referred to as “BDGAC”) is used in the medium of the present embodiment. Since it has the lowest viscosity (EDGAC 2.89 mPa · s / BDGAC 3.63 mPa · s), the viscosity of the ink composition can be reduced by using it as a medium of the ink composition. On the other hand, the total content of diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate is 15 with respect to the total mass of the inkjet ink composition because it deteriorates the pigment dispersibility and also has the PP attack property. It is preferably less than mass%. More preferably, it is 10 mass% or less.

<Other ingredients>
The inkjet ink composition of the present embodiment includes, as other components, a resin such as a styrene acrylic acid copolymer, a wax, a dissolution aid, a viscosity modifier, a pH modifier such as potassium hydroxide or triethanolamine, and an antioxidant. Various additives such as agents, fungicides / antiseptics, antifungal agents, corrosion inhibitors, and chelating agents for capturing metal ions that affect dispersion (eg, sodium ethylenediaminetetraacetate) are appropriately contained. You can also

[Ink composition]
The ink composition of the present embodiment can be prepared by mixing the above-mentioned components in any order and performing filtration or the like as necessary to remove impurities and foreign substances. As a method of mixing each component, a method of sequentially adding the materials to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer, and stirring and mixing is used. As a method of filtration, centrifugal filtration, filter filtration, etc. can be adopted.

The viscosity of the ink composition of the present embodiment can be easily set within a proper range as an inkjet ink composition from the viewpoint of a balance between image quality and reliability as an ink composition. The viscosity of the ink composition according to this embodiment at 20 ° C. is, for example, 2 mPa · s or more and 50 mPa · s or less, preferably 2 mPa · s or more and 35 mPa · s or less, and 2 mPa · s or more and 25 mPa · s or less. Is more preferable.
To measure the viscosity, use a viscoelasticity tester MCR301 (manufactured by Anton-Paar) to increase the Shear Rate to 10 to 1000 under an environment of 20 ° C., and read the viscosity when the Shear Rate is 200. Can be measured by

  The inkjet ink composition according to the present embodiment preferably has a surface tension of 20 mN / m or more and 50 mN / m at 20 ° C., and 25 mN / m from the viewpoint of a balance between image quality and reliability as an inkjet ink. It is more preferably 40 mN / m or less. The surface tension is measured by using an automatic surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.) and confirming the surface tension when the platinum plate is wetted with ink in an environment of 20 ° C. can do.

  The content of water in the inkjet ink composition can be measured by a Karl Fischer moisture meter MKA-520 (manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

  The content of the organic solvent component in the present embodiment is, for example, gas chromatography mass spectrometry (GC / MS), liquid chromatography-mass spectrometry (LC / MS), electric field desorption mass spectrometry (FD / MS). It can be measured by conducting an analysis using the above and the like alone or in combination.

[Inkjet recording method]
In the recording method using the inkjet ink composition of the present embodiment, for example, a printer or the like loaded with the inkjet ink composition is used to eject ink as droplets from an inkjet head based on a digital signal, and a recording medium (for example, plain paper). , Coated paper, art paper, double-sided printing on plain paper, etc.) to obtain an inkjet print. Here, when an inkjet ink composition having a good pigment dispersibility is used, continuous ejection is possible without clogging of the pigment aggregates with the head, and thus an arbitrary inkjet print can be obtained.

  Further, in this step, in the curl, water contained in the ink composition penetrates into the recording medium and swells (for example, the hydrogen bond of the cellulose fiber is cut), and then the water evaporates to reduce the swelling ( For example, hydrogen bonds are regenerated in the cellulose fiber). Therefore, curling can be suppressed by suppressing the content of water in the ink composition.

  As described above, according to the inkjet ink composition of the present embodiment, it is possible to provide a low-moisture ink having excellent pigment dispersion stability and less curl.

  Hereinafter, the effects of the present embodiment will be described more specifically with reference to Examples and Comparative Examples of the ink composition of the present embodiment.

[Preparation of ink composition]
Each material was mixed with the composition shown in Table 1 below, and sufficiently stirred to obtain each composition. The unit of numerical values in Table 1 below is% by mass, and the total is 100.0% by mass. In addition, it means that a column without a numerical value is not included.

  Of the components in the table, for triethylene glycol (TEG), 2-pyrrolidone (2P), triethylene glycol monobutyl ether (TEGmBE), diethylene glycol monoethyl ether acetate (EDGAC), diethylene glycol monobutyl ether acetate (BDGAC), It is described using the abbreviations in the above parentheses.

  The ink composition of Example 1 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 5% by mass, and the content of TEG was 33% by mass. .

  The ink composition of Example 2 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 10% by mass, and the content of TEG was 25% by mass. .

  The ink composition of Example 3 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 20% by mass, and the content of TEG was 24% by mass. .

  The ink composition of Example 4 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 30% by mass, and the content of TEG was 32% by mass. .

  The ink composition of Example 5 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 40% by mass, and the content of TEG was 42% by mass. .

  The ink composition of Example 6 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 10% by mass, and the content of TEG was 45% by mass. .

  The ink composition of Example 7 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition was 20% by mass, and the content of TEG was 36% by mass. .

  The ink composition of Example 8 contains C.I. I. Pigment Black 7 contained BDGAC, TEGmBE, TEG, and 2P as an organic solvent, and the content of water in the ink composition was 20% by mass, and the content of TEG was 36% by mass. .

  The ink composition of Example 9 contained C.I. I. Pigment Black 7 contains EDGAC, BDGAC, TEGmBE, TEG, 2P as an organic solvent, and the content of water in the ink composition is 20% by mass, and the content of TEG is 36% by mass. there were.

  The ink composition of Comparative Example 1 contained C.I. I. Pigment Black 7 was contained as an organic solvent in TEG, and the content of water in the ink composition was 60% by mass, and the content of TEG was 33% by mass.

  The ink composition of Comparative Example 2 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, and TEG as an organic solvent, and the content of water in the ink composition was 30% by mass, and the content of TEG was 15% by mass.

  The ink composition of Comparative Example 3 contained C.I. I. Pigment Black 7 contained EDGAC and TEGmBE as an organic solvent, and the content of water in the ink composition was 30% by mass, and the content of TEG was 0% by mass.

  The ink composition of Comparative Example 4 contained C.I. I. Pigment Black 7 contained EDGAC, TEGmBE, and TEG as an organic solvent, and the content of water in the ink composition was 20 mass%, and the content of TEG was 10 mass%.

[Evaluation]
The ink compositions of Examples and Comparative Examples were evaluated as described below, and the evaluation results are shown in the table.

<Paper stackability>
Paper stackability was evaluated as an evaluation index of curl generated during printing. Specifically, an inkjet recording device (inkjet printer PX-M7050 (manufactured by Seiko Epson Corp.)) is prepared, and each ink composition is filled in an ink cartridge of the inkjet recording device, and A4 size plain paper (product name P (Fuji Xerox Co., Ltd.) at a temperature of 25 ° C. and a humidity of 50%, and 50 solid patterns were continuously printed under the following pattern conditions and standard mode of plain paper.
(Pattern condition)
Print Duty = 100%, edge width = 1 mm, print area = whole recording medium.
(Evaluation criteria)
A: You can stack all 50 cards.
B: You can stack up to 30 sheets.
C: You can stack up to 15 cards.
D: I can't stack 5 cards.

<Pigment dispersibility>
20 g of each ink composition was placed in a screw tube of 30 cc, and the rate of change in viscosity and the presence or absence of precipitation when left for 1 week in an environment of temperature 25 ° C. and humidity 50% were evaluated. Here, a viscoelasticity tester (MCR301, Anton-Paar) was used for viscosity measurement.
(Evaluation criteria)
A: No precipitation occurred after 1 week, and the rate of change in viscosity was less than 5%.
B: No precipitation occurred after 1 week, and the viscosity change rate was less than 10%.
C: Precipitation occurs after 1 week.
D: Precipitation occurs immediately after the preparation of the ink composition.

<PP attack property>
The PP attack property is a property related to the amount of deformation when a printed matter is inserted into a polypropylene (PP) clear folder. In an ink composition with a low water content and a high organic solvent content, when a printed matter is sandwiched between polypropylene (PP) clear folders, the organic solvent moves to the clear folders, so that only the inside of the clear folders is It swells and warps so that the clear folder rises outwards, or wavy and deforms. In particular, when a printed matter recorded with a high duty on a recording medium is sandwiched between clear folders, there is a problem in that the clear folders are largely warped outward and a problem occurs in use.

Each ink composition was applied to A4 size Xerox P paper at a temperature of 25 ° C. and a humidity of 50% using a # 2 bar coater, and then inserted into a PP clear folder. The clear folder in which the printed matter was inserted was left horizontally for 1 week in an environment of a temperature of 25 ° C. and a humidity of 50%. After that, the amount of the outwardly warped clear folder was measured using a ruler, and the value was evaluated as the amount of deformation.
(Evaluation criteria)
A: Deformation amount less than 10 mm.
B: Deformation amount 10 mm or more and less than 20 mm.
C: Deformation amount 20 mm or more and less than 30 mm.
D: Deformation amount of 30 mm or more.

  As shown in Table 2, it can be seen that the ink compositions of Examples 1 to 9 have a B level of pigment dispersibility that is equal to or higher than the B level, which corresponds to an “appropriate” level. Regarding the paper stacking property, it can be seen that the ink compositions of Examples 1 to 9 have a C judgment or higher corresponding to the “OK” level. Here, among the ink compositions of the examples, when the water content in the ink composition is less than 40% by mass, the paper stacking property is B judgment or more corresponding to the “adequate” level. From the results, it is more preferable that the content of water in the ink composition is less than 40% by mass.

  Regarding the PP attack property as well, it can be seen that the ink compositions of Examples 1 to 9 have the C judgment or higher corresponding to the “OK” level. Here, among the ink compositions of the examples, those in which the total content of EDGAC and BDGAC is less than 15% by mass based on the total mass of the ink composition are B judgment or higher corresponding to “adequate” level. Therefore, it is understood that the total content of EDGAC and BDGAC in the ink composition is preferably less than 15% by mass.

  On the other hand, the ink composition of Comparative Example 1 was D-judgment corresponding to the "impossible" level in the paper stacking property, and Comparative Examples 2 to 4 could not ensure the pigment dispersibility, so the paper stacking property was evaluated. It could not be carried out. Further, in Comparative Examples 2 to 4 in which the total content of EDGAC and BDGAC was more than 15% by mass based on the total mass of the ink composition, the PP attack property was D judgment corresponding to the “impossible” level.

  As described above, as is clear from the results shown in Table 2, the inkjet ink composition according to the present embodiment is a low-curl low-moisture ink having excellent pigment dispersion stability as compared with the comparative example. I understand.

  The contents derived from the embodiment will be described below.

  The inkjet ink composition contains a pigment, water, triethylene glycol, 2-pyrrolidone, triethylene glycol monobutyl ether, and diethylene glycol monoethyl ether acetate, or diethylene glycol monobutyl ether acetate, and The content of water is less than the content of triethylene glycol based on the total mass of the inkjet ink composition.

  According to this configuration, it is possible to realize a low water content ink with excellent curl dispersion stability and less curl. By blending the composition for inkjet ink with highly hydrophilic triethylene glycol and 2-pyrrolidone in such a relationship as described above, the dispersibility of the pigment can be secured even in a composition having a low water content. . Furthermore, the viscosity is low, curl does not occur triethylene glycol monobutyl ether and diethylene glycol monoethyl ether acetate, or by containing diethylene glycol monobutyl ether acetate, not only the dispersibility of the pigment, but also the curl A low amount of low-moisture ink can be realized.

  The inkjet ink composition preferably has a water content of 40% by mass or less based on the total mass of the inkjet ink composition.

  With this configuration, curling due to water can be reduced. Specifically, by setting the content of water to 40% by mass or less based on the total mass of the inkjet ink composition, the water contained in the ink composition permeates into the recording medium and swells (for example, cellulose fibers). C.), and then swelling is mitigated by water evaporating (for example, hydrogen bonds are regenerated in the cellulose fiber), and thus curling can be suppressed.

  The inkjet ink composition is preferably an inkjet ink composition in which the total content of diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate is less than 15% by mass based on the total mass of the inkjet ink composition. .

  According to this configuration, it is possible to reduce the PP attack property while reducing the viscosity of the ink composition by blending diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate.

  The inkjet ink composition is preferably an inkjet ink composition in which the content of triethylene glycol is equal to or more than the content of 2-pyrrolidone with respect to the total mass of the inkjet ink composition.

  According to this configuration, it is possible to reduce the viscosity of the ink composition by 2-pyrrolidone while suppressing the deterioration of the curling property by 2-pyrrolidone, which has the worst curling property among the organic solvents of the present embodiment.

Claims (4)

Pigment, water, triethylene glycol, 2-pyrrolidone, triethylene glycol monobutyl ether,
Containing either diethylene glycol monoethyl ether acetate or diethylene glycol monobutyl ether acetate,
The inkjet ink composition, wherein the content of water is less than the content of the triethylene glycol with respect to the total mass of the inkjet ink composition.   The inkjet ink composition according to claim 1, wherein the content of water is 40% by mass or less based on the total mass of the inkjet ink composition.   The inkjet ink composition according to claim 1 or 2, wherein the total content of the diethylene glycol monoethyl ether acetate and the diethylene glycol monobutyl ether acetate is less than 15% by mass based on the total mass of the inkjet ink composition. object.   The inkjet ink composition according to any one of claims 1 to 3, wherein the content of the triethylene glycol is equal to or more than the content of the 2-pyrrolidone with respect to the total mass of the inkjet ink composition.