Inkjet ink

Abstract

To provide an inkjet ink that has a low viscosity and a low freezing point, enables suppression of swelling of rubber members, and has excellent ejection stability without using mineral oils, such as MOAH and MOSH.SOLUTION: An ink comprises a saturated fatty acid monoester having a flash point of 125 to 170°C and a viscosity at 20°C of 4.0 to 10.0 mPa s (1), a saturated fatty acid monoester having a flash point of 170 to 200°C (2), and a plasticizer, comprising two or more saturated fatty acid diesters each having a flash point of 125 to 220°C, or a saturated fatty acid diester having a flash point of 125 to 220°C and a saturated fatty acid monoester having a flash point of 125 to 170°C and a viscosity at 20°C of 0.1 to 4.0 mPa s (3), and the total content of the saturated fatty acid monoester (1) and the saturated fatty acid monoester (2) is 53.0 to 63.0 mass% based on the total amount of the ink taken as 100 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to ink-jet inks. [Background technology]

[0002] An inkjet recording system is a printing system that prints by ejecting highly fluid liquid ink from minute nozzles onto a recording medium such as paper. This inkjet recording system has recently become increasingly popular due to its ability to print high-resolution, high-quality images at high speed and with low noise using relatively inexpensive equipment.

[0003] Among these, the piezoelectric inkjet method uses a piezoelectric element (piezo element) that changes volume when voltage is applied, and ink is ejected from the inkjet head by vibration in response to the volume change of the piezo element. This piezoelectric inkjet method allows for precise control of the ink ejection volume through voltage control, and because it does not require heating, it is less affected by the usage environment and is highly durable.

[0004] However, oil-based inkjet inks used in piezoelectric inkjet systems (piezo inkjet inks) must meet various requirements. First, they must be resistant to evaporation, preventing loss of ejection stability due to evaporation. Second, to prevent clogging of inkjet heads, oil-based inkjet inks used in piezoelectric inkjet systems (piezo inkjet inks) must have low viscosity; the higher the resolution of the head, the lower the viscosity required. Specifically, a viscosity of 15.0 mPa·s or less at 20°C is required. Second, the inkjet ink must prevent swelling of rubber components such as rubber gaskets that make up the inkjet head. Furthermore, considering winter use, the inkjet ink must have a freezing point below freezing to prevent clogging due to solidification.

[0005] In order to satisfy the various requirements described above, inkjet inks used in piezoelectric inkjet systems (piezo inkjet inks) often contain petroleum hydrocarbons, such as liquid paraffin, as the solvent. Summary of the Invention [Problem to be solved by the invention]

[0006] However, due to concerns about the risks to the human body, the French government has restricted the use of mineral oil and banned the use of oils and fats made from petroleum hydrocarbons used in ink production from January 1, 2023. This means that mineral oil aromatic hydrocarbons (MOAH), which contain 1 to 7 aromatic rings, and mineral oil saturated hydrocarbons (MOSH), which contain 16 to 35 carbon atoms, can no longer be used.

[0007] Therefore, there is a demand for an inkjet ink that satisfies the above-mentioned various requirements without using mineral oils such as MOAH and MOSH.

[0008] Therefore, an object of the present invention is to provide an inkjet ink that has low viscosity and freezing point, can suppress swelling of rubber members, and has excellent ejection stability without using mineral oils such as MOAH and MOSH. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to achieve the above-mentioned object. As a result, they have found that by using a saturated fatty acid monoester having a specific flash point and a saturated fatty acid diester having a specific flash point, and by controlling the content of the saturated fatty acid monoester within a specific range, an oil-based inkjet ink can be obtained that has a low viscosity and freezing point, can suppress swelling of rubber components, and has excellent ejection stability, even without using mineral oils such as MOAH or MOSH. Based on this finding, the present inventors have conducted further research and completed the present invention. That is, the present invention includes the following features.

[0010] Item 1. A saturated fatty acid monoester (1) having a flash point of 125 to 170°C and a viscosity at 20°C of 4.0 to 10.0 mPa·s; A saturated fatty acid monoester (2) having a flash point of 170 to 200°C; and a plasticizer, The plasticizer contains two or more saturated fatty acid diesters having a flash point of 125 to 220°C, or a saturated fatty acid diester having a flash point of 125 to 220°C and a saturated fatty acid monoester (3) having a flash point of 125 to 170°C and a viscosity at 20°C of 0.1 to 4.0 mPa·s, and the total content of the saturated fatty acid monoester (1) and the saturated fatty acid monoester (2) is 53.0 to 63.0% by mass, with the total amount of the ink being 100% by mass; Inkjet ink.

[0011] Item 2. The ink-jet ink according to Item 1, wherein the ratio of the content of the saturated fatty acid monoester (1) to the content of the saturated fatty acid monoester (2) (saturated fatty acid monoester (2) / saturated fatty acid monoester (1)) is 0.20 to 0.80.

[0012] Item 3. The ink-jet ink according to Item 1 or 2, wherein the content of the plasticizer is 15.0 to 35.0% by mass in total, with the total amount of the ink being 100% by mass.

[0013] Item 4. The inkjet ink according to any one of Items 1 to 3, further comprising a pigment and / or a dye.

[0014] Item 5. The inkjet ink according to any one of Items 1 to 4, further comprising a pigment derivative and / or a pigment dispersant.

[0015] Item 6. The inkjet ink according to any one of Items 1 to 5, which does not contain mineral oil.

[0016] Item 7. The inkjet ink according to any one of Items 1 to 6, which is an oil-based inkjet ink.

[0017] Item 8. The ink-jet ink according to any one of Items 1 to 7, which is a piezoelectric ink-jet ink.

[0018] Item 9. An inkjet ink container containing the inkjet ink according to any one of items 1 to 8.

[0019] Item 10. A printed matter printed on a printing substrate with the inkjet ink according to any one of Items 1 to 8.

[0020] Item 11. The printed matter according to Item 10, wherein the printing substrate is a porous material. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide an oil-based inkjet ink that has low viscosity and freezing point, can suppress swelling of rubber components, and has excellent ejection stability, without using mineral oils such as MOAH and MOSH. DETAILED DESCRIPTION OF THE INVENTION

[0022] In this specification, the term "containing" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of."

[0023] In this specification, when a numerical range is expressed as A to B, it means A or more and B or less.

[0024] 1. Inkjet ink The inkjet ink of the present invention comprises: a saturated fatty acid monoester (1) having a flash point of 125 to 170°C and a viscosity at 20°C of 4.0 to 10.0 mPa·s; A saturated fatty acid monoester (2) having a flash point of 170 to 200°C; and a plasticizer, The plasticizer contains two or more saturated fatty acid diesters having a flash point of 125 to 220°C, or a saturated fatty acid diester having a flash point of 125 to 220°C and a saturated fatty acid monoester (3) having a flash point of 125 to 170°C and a viscosity at 20°C of 0.1 to 4.0 mPa·s, and The total content of the saturated fatty acid monoester (1) and the saturated fatty acid monoester (2) is 53.0 to 63.0% by mass, with the total amount of ink being 100% by mass.

[0025] (1-1) Saturated fatty acid monoester (1) The present invention contains a saturated fatty acid monoester (1) having a flash point of 125 to 170° C. and a viscosity of 4.0 to 10.0 mPa·s at 20° C. If the saturated fatty acid monoester (1) is not contained, the resulting inkjet ink will have a high viscosity, making it impossible to prevent clogging in the inkjet head; it will have a high freezing point, making it impossible to prevent clogging due to solidification in winter; rubber components will be prone to swelling, causing ink to leak from the inkjet device and resulting in a lack of stable printer operation; and it will be prone to volatilization and have poor ejection stability.

[0026] The flash point of the saturated fatty acid monoester (1) is 125 to 170°C, preferably 127 to 168°C, from the viewpoints of viscosity, freezing point, suppression of swelling of rubber components, and ejection stability. If the flash point of the saturated fatty acid monoester (1) is less than 125°C, it will be prone to volatilization, resulting in poor ejection stability, and the rubber components will be prone to swelling, leading to ink leakage from the inkjet device and other problems that hinder stable printer operation. If the flash point of the saturated fatty acid monoester (1) is greater than 170°C, the viscosity of the resulting inkjet ink will be high, making it impossible to suppress clogging in the inkjet head, and the freezing point will be high, making it impossible to prevent clogging due to solidification in winter.

[0027] The viscosity of the saturated fatty acid monoester (1) at 20°C is 4.0 to 10.0 mPa·s, preferably 4.5 to 8.0 mPa·s, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber components, ejection stability, etc. If the viscosity of the saturated fatty acid monoester (1) at 20°C is less than 4.0 mPa·s, the flash point will be low and the ink will volatilize in the nozzle, preventing stable operation. If the viscosity of the saturated fatty acid monoester (1) at 20°C exceeds 10.0 mPa·s, the viscosity of the ink will increase and stable ejection will be impossible.

[0028] The boiling point of the saturated fatty acid monoester (1) is not particularly limited, but is preferably 100 to 200°C, more preferably 130 to 180°C, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc. Note that, from the viewpoint of easily keeping the viscosity of the inkjet ink low, it is preferable to have a small molecular weight and not have an excessively high boiling point. Furthermore, from the viewpoint of easily lowering the melting point and therefore the solidification point, it is also preferable that the boiling point is not too high.

[0029] Examples of saturated fatty acid monoesters (1) that satisfy the above conditions include isopropyl myristate, butyl myristate, and butyl laurate. The saturated fatty acid monoesters (1) can be used alone or in combination of two or more. Known or commercially available saturated fatty acid monoesters (1) can be used.

[0030] (1-2) Saturated fatty acid monoester (2) In the present invention, the ink contains a saturated fatty acid monoester (2) having a flash point of 170 to 200° C. If the ink does not contain the saturated fatty acid monoester (2), the viscosity of the resulting inkjet ink is high, making it impossible to prevent clogging in the inkjet head; the freezing point is high, making it impossible to prevent clogging due to freezing in winter; the ink is prone to swell in rubber components, causing ink leakage from the inkjet device and other problems that hinder stable printer operation; and the ink is prone to volatilization, resulting in poor ejection stability.

[0031] The flash point of the saturated fatty acid monoester (2) is 170 to 200°C, preferably 175 to 195°C, from the viewpoints of viscosity, freezing point, suppression of swelling of rubber components, ejection stability, etc. If the flash point of the saturated fatty acid monoester (2) is less than 170°C, the rubber components are likely to swell, resulting in ink leakage from the inkjet device and other problems that hinder stable printer operation. If the flash point of the saturated fatty acid monoester (2) is more than 200°C, the viscosity of the resulting inkjet ink is high, making it impossible to suppress clogging in the inkjet head; the freezing point is high, making it impossible to prevent clogging due to solidification in winter; and the high viscosity of the ink makes it impossible to eject the ink stably.

[0032] The viscosity of the saturated fatty acid monoester (2) at 20°C is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, discharge stability, etc., it is preferably 4.0 to 10.0 mPa·s, and more preferably 5.0 to 9.0 mPa·s.

[0033] The boiling point of the saturated fatty acid monoester (2) is not particularly limited, but is preferably 100 to 200° C., more preferably 130 to 180° C., from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc. Note that, from the viewpoint of easily maintaining a low viscosity of the inkjet ink, it is preferable that the molecular weight is small and the boiling point is not too high.

[0034] Examples of saturated fatty acid monoesters (2) that satisfy the above conditions include isopropyl palmitate and ethyl palmitate. The saturated fatty acid monoesters (2) can be used alone or in combination of two or more. Known or commercially available saturated fatty acid monoesters (2) can be used.

[0035] (1-3) Plasticizer In the present invention, the plasticizer may be: Two or more saturated fatty acid diesters with a flash point of 125 to 220°C, or It contains a saturated fatty acid diester having a flash point of 125 to 220°C and a saturated fatty acid monoester (3) having a flash point of 125 to 170°C and a viscosity at 20°C of 0.1 to 4.0 mPa·s.

[0036] If only one saturated fatty acid diester having a flash point of 125 to 220°C is used and no saturated fatty acid monoester (3) is used, the viscosity of the resulting inkjet ink is high and clogging in the inkjet head cannot be suppressed, the freezing point is high and clogging due to solidification cannot be prevented in winter, the rubber components are prone to swelling, and the ink leaks from the inkjet device, resulting in a lack of stable operation of the printer, and the ink is prone to volatilization and has poor ejection stability.

[0037] saturated fatty acid diester The flash point of the saturated fatty acid diester is preferably 125 to 220°C, more preferably 140 to 210°C, from the viewpoints of viscosity, freezing point, suppression of swelling of rubber members, ejection stability, etc. If the flash point of the saturated fatty acid diester is less than 125°C, it will be prone to volatilization and will have poor ejection stability. If the flash point of the saturated fatty acid diester is more than 220°C, the viscosity of the resulting inkjet ink will be too high, making it impossible to suppress clogging in the inkjet head, and the freezing point will be too high, making it impossible to prevent clogging due to solidification in winter.

[0038] The viscosity of the saturated fatty acid diester at 20°C is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, discharge stability, etc., it is preferably 4.0 to 20.0 mPa·s, and more preferably 5.0 to 15.0 mPa·s.

[0039] Examples of saturated fatty acid diesters that satisfy the above conditions include dibutyl sebacate, diethylhexyl sebacate, dibutyl adipate, and diethylhexyl adipate. The saturated fatty acid diesters can be used alone or in combination of two or more. When using one saturated fatty acid diester, dibutyl sebacate is most preferred from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, and discharge stability. When using two or more saturated fatty acid diesters, it is preferred that one be dibutyl sebacate and the other be another saturated fatty acid diester from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, and discharge stability. Known or commercially available saturated fatty acid diesters can be used.

[0040] Saturated fatty acid monoesters (3) The flash point of the saturated fatty acid monoester (3) is preferably 125 to 170°C, and more preferably 130 to 168°C, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, discharge stability, and the like.

[0041] The viscosity of the saturated fatty acid monoester (3) at 20°C is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, discharge stability, etc., it is preferably 1.0 to 5.0 mPa·s, and more preferably 2.0 to 4.0 mPa·s.

[0042] Examples of saturated fatty acid monoesters (3) that satisfy the above conditions include methyl laurate. The saturated fatty acid monoesters (3) can be used alone or in combination of two or more. Known or commercially available saturated fatty acid monoesters (3) can be used.

[0043] (1-4) Solvent content As described above, the inkjet ink of the present invention contains saturated fatty acid monoester (1), saturated fatty acid monoester (2), and a plasticizer, and the contents of each component are preferably as follows:

[0044] The content of saturated fatty acid monoester (1) is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 30.0 to 50.0 mass%, and more preferably 35.0 to 45.0 mass%, based on 100 mass% of the total amount of the inkjet ink of the present invention.

[0045] The content of saturated fatty acid monoester (2) is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 5.0 to 33.0 mass %, and more preferably 10.0 to 27.0 mass %, based on 100 mass % of the total amount of the inkjet ink of the present invention.

[0046] The total content of the saturated fatty acid monoester (1) and the saturated fatty acid monoester (2) is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 53.0 to 63.0 mass%, and more preferably 55.0 to 62.0 mass%, based on 100 mass% of the total amount of the inkjet ink of the present invention.

[0047] The ratio of the saturated fatty acid monoester (1) to the saturated fatty acid monoester (2) (saturated fatty acid monoester (2) / saturated fatty acid monoester (1)) is not particularly limited, but is preferably 0.20 to 0.80, more preferably 0.25 to 0.70, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, discharge stability, etc.

[0048] The total content of the plasticizer is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 15.0 to 35.0 mass%, and more preferably 24.0 to 33.0 mass%, of the total amount of the inkjet ink of the present invention being 100 mass%.

[0049] When dibutyl sebacate is contained as a plasticizer, its content is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 10.0 to 30.0 mass%, and more preferably 12.0 to 28.0 mass%, of the total amount of the inkjet ink of the present invention being 100 mass%.

[0050] Furthermore, when saturated fatty acid diesters other than dibutyl sebacate and saturated fatty acid monoesters (3) are contained as plasticizers, their total content is not particularly limited, but from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc., it is preferably 2.0 to 25.0 mass %, and more preferably 3.0 to 20.0 mass %, relative to 100 mass % of the total amount of the inkjet ink of the present invention.

[0051] In the present invention, saturated fatty acid monoester (1) and saturated fatty acid monoester (2) are used as solvents, and the above-mentioned plasticizers can also serve as solvents. Therefore, the inkjet ink of the present invention can be an oil-based inkjet ink that uses an organic solvent as a solvent.

[0052] Furthermore, the use of water, ketones, alcohols, etc., which are often used as solvents in aqueous inkjet inks, is not completely excluded. However, as will be described later, the inkjet ink of the present invention is intended for use on porous substrates such as paper as the printing substrate, and water, ketones, alcohols, etc. tend to soak into the printing substrate. Therefore, it is preferable not to use water, ketones (acetone, methyl ethyl ketone, dipropyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, etc.), alcohols (methanol, ethanol, propanol, isopropyl alcohol, etc.), etc., or to use them in an amount of 1% by mass or less, with the total amount of the inkjet ink of the present invention being 100% by mass.

[0053] (1-5) Pigments and / or dyes As described above, the inkjet ink of the present invention contains the saturated fatty acid monoester (1), the saturated fatty acid monoester (2), and a plasticizer. In addition, the inkjet ink of the present invention may contain other components that are typically contained in inkjet inks, such as pigments (color pigments, fluorescent pigments, etc.) and / or dyes (color dyes, fluorescent dyes, etc.).

[0054] Colorant pigment The color pigment is not particularly limited as long as it can exhibit a non-fluorescent color. Color pigments can be roughly divided into inorganic pigments and organic pigments, and either can be used.

[0055] Suitable inorganic color pigments include, for example, carbon black, titanium oxide, calcium carbonate, iron oxide, and cobalt blue.

[0056] Examples of organic colorant pigments include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow, and pyrazolone red; pigments derived from vat dyes such as alizarin, indanthrone, and thioindigo maroon; soluble azo pigments such as lithol red, helio bordeaux, pigment scarlet, and permanent red 2B; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; quinacridone pigments such as quinacridone red and quinacridone magenta; isoindolinone pigments such as isoindolinone yellow and isoindolinone orange; pyranthrone pigments such as pyranthrone red and pyranthrone orange; and other pigments such as flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, and dioxazine violet.

[0057] The above color pigments are listed by Color Index (CI) numbers: CI Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 109, 110, 117, 125, 128, 129, 137, 139, 147, 148, 151, 153, 154, 181, 166, 168, 185, etc.; CI Pigment Orange 16, 36, 43, 51, 55, 59, 61, etc.; CI Pigment Red 9, 48, 49, 52, 53, 57 , 97, 122, 123, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, etc.; CI Pigment Violet 19, 23, 30, 37, 40, 50, etc.; CI Pigment Blue 15, 15:1, 15:3, 15:4, 15:6, 22, 60, 64, etc.; CI Pigment Green 7, 36, etc.; CI Pigment Brown 23, 25, 26, etc.

[0058] The above-mentioned color pigments can be used alone or in combination of two or more kinds in consideration of visibility under visible light, color, etc. Furthermore, known or commercially available color pigments can be used.

[0059] Unlike colorant dyes, the colorant pigments described above are present in the inkjet ink in a dispersed state without being dissolved.

[0060] The color pigment can be made into a stable dispersion by stirring it at high speed together with a dispersant in a dispersing machine.

[0061] fluorescent pigment Examples of fluorescent pigments include inorganic fluorescent pigments such as aluminates, such as magnesium aluminometasilicate and magnesium aluminosilicate, and organic fluorescent pigments such as perylene pigments, such as perylene red and perylene scarlet; and other pigments, such as quinophthalone yellow and diketopyrrolopyrrole.

[0062] The above-mentioned fluorescent pigments can be expressed by Color Index (CI) numbers as follows: CI Pigment Yellow 138; CI Pigment Orange 71, 73, etc.; CI Pigment Red 254, 255, 264, etc.; CI Pigment Violet 29, etc.

[0063] Unlike fluorescent dyes, the fluorescent pigments described above are not dissolved but are dispersed in the inkjet ink.

[0064] The fluorescent pigment can be made into a stable dispersion by stirring at high speed together with a dispersant in a dispersing machine.

[0065] color dye Examples of colorant dyes, as indicated by Color Index (CI) numbers, include CI Solvent Yellow 2, 14, 16, 19, 21, 34, 48, 56, 79, 88, 89, 93, 95, 98, 133, 137, 147, etc.; CI Solvent Orange 5, 6, 45, 60, 63, etc.; CI Solvent Red 1, 3, 7, 8, 9, 18, 23, 24, 27, 49, 83, 100, 111, 122, 125, 130, 132, 135, 195, 202, 212, etc.; CI Solvent Blue 2, 3, 4, 5, 7, 18, 25, 26, 35, 36, 37, 38, 43, 44, 45, 47, 48, 51, 58, 59, 59:1, 63, 64, 67, 68, 69, 70, 78, 79, 83, 94, 97, 98, 99, 100, 101, 102, 104, 105, 111, 112, 122, 124, 128, 129, 132, 136, 137, 138, 139, 143, etc.; CI Solvent Green 5, 7, 14, 15, 20, 35, 66, 122, 125, 131, etc.; CI Solvent Black 1, 3, 6, 22, 27, 28, 29, etc.; CI Solvent Violet 13, etc.; CI Solvent Brown 1, 53, etc. Basic oil dyes can also be used. Examples of such basic oil dyes include CI Basic Violet 3; CI Basic Red 1, 8, etc.; CI Basic Black 2, etc.

[0066] Unlike color pigments, the color dyes described above are present in the inkjet ink in a dissolved state.

[0067] These coloring dyes may be used alone or in combination of two or more. Known or commercially available coloring dyes may be used.

[0068] fluorescent dye As the fluorescent dye, various fluorescent dyes can be used which are dissolved in a solvent and are not visible or are difficult to see under visible light, but which fluoresce and become visible when irradiated with ultraviolet light from a black light or the like.

[0069] Examples of such fluorescent dyes include benzoxazole derivatives such as 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene and 1,4-bis(2-benzoxazolyl)naphthalene; and stilbene derivatives such as 4,4'-bis(triazin-2-ylamino)stilbene-2,2'-disulfonic acid derivatives, in which the triazinyl group is, for example, an anilino, sulfanilic acid, metanilic acid, methylamino, N-methyl-N-hydroxyethylamino, bis(hydroxyethylamino), morpholino, diethylamino, and the like. Stilbene derivatives substituted with amino or other substituents; mono(azol-2-yl)stilbene derivatives such as 2-(stilben-4-yl)naphthotriazole and 2-(4-phenylstilben-4-yl)benzoxazole; bis(azol-2-yl)stilbene derivatives such as 4,4'-bis(triazol-2-yl)stilbene-2,2'-disulfonic acid; styryl derivatives of benzene or biphenyl such as 1,4-bis(styryl)benzene and 4,4'-bis(styryl)biphenyl; 1,3-diphenyl-2-pyra Pyrazoline derivatives such as zoline; bis(benzazol-2-yl) derivatives having alkyl, COO-alkyl or SO2-alkyl as the phenyl ring substituent; bis(benzoxazol-2-yl) derivatives; bis(benzimidazol-2-yl) derivatives such as 2-(benzofuran-2-yl)benzimidazole; 7-hydroxycoumarin, 7-(amino-substituted)coumarin, 7-diethylamino-4-methylcoumarin, esculetin, β-methylumbelliferone coumarin derivatives such as 3-phenyl-7-(triazin-2-yl-amino)coumarin, 3-phenyl-7-aminocoumarin, 3-phenyl-7-(azol-2-yl)coumarin, 3,7-bis(azolyl)coumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin (coumarin 6); carbostyril; naphthalimide; alkoxynaphthalimide; dibenzothiophene-5,5'-dioxide derivatives; pyrene derivatives; and pyridotriazole.Examples of these fluorescent dyes include NIKKABRIGHT, NIKKAFLUOR, etc. manufactured by Nippon Chemical Industry Co., Ltd.; KAYAPHOR, KAYALIGHT, etc. manufactured by Nippon Kayaku Co., Ltd.; ILLUMINARL manufactured by Showa Kako Co., Ltd.; WHITEX manufactured by Sumitomo Chemical Co., Ltd.; and TINOPAL manufactured by BASF.

[0070] The above-mentioned fluorescent dyes can be used alone or in combination of two or more types in consideration of visibility under ultraviolet light, fluorescence intensity, color, etc. Furthermore, known or commercially available fluorescent dyes can be used.

[0071] Unlike fluorescent pigments, the fluorescent dyes described above exist in a dissolved state in the inkjet ink.

[0072] In the inkjet ink of the present invention, the content of the pigment and / or dye is not particularly limited, but is preferably 3.0 to 20.0% by mass, and more preferably 5.0 to 15.0% by mass, based on 100% by mass of the total amount of the inkjet ink of the present invention, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc. When two or more types of pigments and / or dyes are used, it is preferable to adjust the total content so that it is within the above range.

[0073] (1-6) Pigment derivatives or pigment dispersants In the ink-jet ink of the present invention, particularly when a pigment is used, a pigment derivative or a pigment dispersant may also be used for the purpose of dispersing the pigment.

[0074] Specific examples of pigment derivatives include Solsperse 5000S (manufactured by Lubrizol Corporation).

[0075] Specific examples of pigment dispersants include hydroxyl group-containing carboxylic acid esters, salts of long-chain polyaminoamides and high-molecular-weight acid esters, salts of high-molecular-weight polycarboxylic acids, salts of long-chain polyaminoamides and polar acid esters, polymer copolymers, modified polyurethanes, modified poly(meth)acrylates, polyether ester-type anionic surfactants, naphthalenesulfonic acid formalin condensate salts, aromatic sulfonic acid formalin condensate salts, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonylphenyl ether, polyester polyamines, and stearylamine acetate.

[0076] Specific examples of pigment dispersants having an ester structure or a modified poly(meth)acrylate structure include Solsperse 9000, Solsperse 13940, Solsperse 17000, Solsperse 18000, Solsperse 24000, Solsperse 28000, Solsperse 32000, Solsperse J-180, and Solsperse J-200 (all manufactured by Lubrizol Corporation); DA-703-50, DA-7300, and DA234 (all manufactured by Kusumoto Chemicals Co., Ltd.); and DISPERBYK-2022, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2096, BYKJET-9150, BYKJET-9051, and BYKJET-9052 (all manufactured by BykCemie).

[0077] These pigment derivatives and pigment dispersants may be used alone or in combination of two or more. Known or commercially available pigment derivatives and pigment dispersants may be used.

[0078] When a pigment derivative and a pigment dispersant are used in the inkjet ink of the present invention, the contents of the pigment derivative and the pigment dispersant are not particularly limited, but are preferably 1.5 to 10.0% by mass, and more preferably 2.5 to 7.5% by mass, of the total amount of the inkjet ink of the present invention taken as 100% by mass, from the viewpoints of viscosity, solidification point, suppression of swelling of rubber members, ejection stability, etc. When two or more types of pigment derivatives and pigment dispersants are used, it is preferable to adjust the total content thereof to be within the above ranges.

[0079] (1-7) Other additives In addition to the above components, the inkjet ink of the present invention can contain various components for various purposes, as long as the effects of the present invention are not impaired. For example, components commonly used in inkjet inks, such as conductive agents, surface conditioners, surfactants, and stabilizers, can be contained within their normally used content ranges. Furthermore, the inkjet ink of the present invention does not completely exclude the inclusion of unsaturated fatty acid esters within their normally used content ranges.

[0080] However, even without using mineral oil, the inkjet ink of the present invention has low viscosity and freezing point, can suppress swelling of rubber components, and can be an oil-based inkjet ink with excellent ejection stability. In light of the French government's mineral oil regulations, it is preferable that the inkjet ink of the present invention does not contain mineral oils such as mineral oil aromatic hydrocarbons (MOAH) containing 1 to 7 aromatic rings and mineral oil saturated hydrocarbons (MOSH) containing 16 to 35 carbon atoms. Furthermore, because unsaturated fatty acid esters are prone to degradation due to oxidation of the unsaturated bond moiety and are prone to reducing stability over time, it is preferable that the inkjet ink does not contain unsaturated fatty acid esters.

[0081] (1-8) Inkjet ink The method for producing an inkjet ink containing the above-mentioned components is not particularly limited. For example, the components may be added simultaneously, or the components may be added sequentially in a predetermined order.

[0082] The inkjet ink of the present invention obtained in this manner has a low viscosity and a low freezing point, can suppress swelling of rubber members, and can be an oil-based inkjet ink with excellent ejection stability. Therefore, it is preferable that the inkjet ink of the present invention be an inkjet ink (piezo inkjet ink, particularly drop-on-demand piezoelectric inkjet ink) used in a piezoelectric inkjet system, particularly a drop-on-demand piezoelectric inkjet system.

[0083] Before using the inkjet ink of the present invention in an inkjet recording apparatus, the inkjet ink of the present invention can be stored in a container to form an inkjet ink container for use in storing, transporting, etc., and when using the inkjet ink, the inkjet ink can be supplied to the recording apparatus.

[0084] The shape of the inkjet ink container is not particularly limited, and may be any shape such as a pack, bottle, tank, jar, or can.

[0085] The inkjet ink of the present invention can be applied to printing on a variety of printing substrates.

[0086] The printing substrate is not particularly limited, and examples thereof include paper, metal, glass, plastics, and coated materials formed by coating the surfaces of these materials. However, since the inkjet ink of the present invention is preferably an inkjet ink used in a piezoelectric inkjet system, particularly a drop-on-demand piezoelectric inkjet system (a piezoelectric inkjet ink, particularly a drop-on-demand piezoelectric inkjet ink), the printing substrate is preferably a porous substrate such as paper or cloth.

[0087] By spraying ink droplets of the inkjet ink of the present invention onto the surface of such a printing substrate using an inkjet printer, it is possible to obtain a printed matter on which various codes such as characters, bar codes, data matrix codes, etc. are printed. [Example]

[0088] EXAMPLES The present invention will be specifically explained below by showing examples and comparative examples, but it goes without saying that the present invention is not limited to these examples.

[0089] In the examples, the following commercially available reagents were used: The viscosity of each reagent is measured at 20°C.

[0090] Colorant pigment Carbon black: Cabot REGAL 660R (CI Pigment Black 7).

[0091] Dispersants Solsperse 24000: Manufactured by Lubrizol.

[0092] solvent Isopropyl myristate (IPM): flash point 130°C, viscosity 5.4 mPa·s Isopropyl palmitate (IPP): Flash point 183°C, viscosity 7.4 mPa·s.

[0093] plasticizer Dibutyl sebacate (DBS): Flash point 190°C, viscosity 9.1 mPa·s Diethylhexyl adipate (DOA): Flash point 205°C, viscosity 13.5 mPa·s Dibutyl adipate (DBA): Flash point 166°C, viscosity 6.0 mPa·s Methyl laurate: flash point 136°C, viscosity 2.6 mPa·s Dimethyl adipate (DMA): Flash point 122°C, viscosity 3.3 mPa·s Dioctyl sebacate (DOS): Flash point 222°C, viscosity 20.9 mPa·s.

[0094] mineral oil Liquid paraffin 40S: manufactured by Sanko Chemical Industry Co., Ltd.

[0095] Example 1 As shown in Table 1, isopropyl myristate (IPM; 36.5 parts by mass), isopropyl palmitate (IPP; 20.0 parts by mass), dibutyl sebacate (DBS; 25.0 parts by mass), and diethylhexyl adipate (DOA; 5.0 parts by mass) were mixed with Solsperse 24000 (4.5 parts by mass) as a dispersant and carbon black (9.0 parts by mass) as a color pigment, and the mixture was subjected to a dispersion treatment in a horizontal sand mill (Dynomill Multilab, manufactured by Willy & Bachofen) at a peripheral speed of 12 m / sec for 2 hours, and then filtered through a filter with 1 μm openings to prepare the inkjet ink of Example 1.

[0096] Examples 2 to 6 and Comparative Examples 1 to 10 As shown in Tables 1 and 2, inkjet inks of Examples 2 to 6 and Comparative Examples 1 to 10 were prepared in the same manner as in Example 1, except that the types and contents of the solvent, plasticizer, and mineral oil were variously adjusted.

[0097] Rating 1: Viscosity The viscosity of the inkjet inks of Examples 1 to 6 and Comparative Examples 1 to 10 was measured at a measurement temperature of 20°C using a rotating disk viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Because the inks are ejected from the inkjet nozzle at high speed, a low viscosity is preferred. ○: 12.5mPa·s or less △: More than 12.5 mPa·s and 15.0 mPa·s or less ×: Greater than 15.0 mPa·s It was evaluated as follows.

[0098] Rating 2: Freezing point The freezing points of the inkjet inks of Examples 1 to 6 and Comparative Examples 1 to 10 were measured in accordance with JISK 0065:1992 (Method for measuring the freezing point of chemical products). Assuming use in winter, a lower freezing point is preferable. ○: -3℃ or below ×: Higher than -3℃ It was evaluated as follows.

[0099] Rating 3: Swelling A rubber part (O-ring S11.2 Type 4 D) was immersed in the inkjet inks of Examples 1 to 6 and Comparative Examples 1 to 10 at 45°C for one month, and the change in weight before and after immersion was measured. ○: Weight change is 10% by mass or less ×: Weight change is greater than 10% by mass It was evaluated as follows.

[0100] Rating 4: Mineral oil In the inkjet inks of Examples 1 to 6 and Comparative Examples 1 to 10, the following was confirmed regarding the mineral oil regulations imposed by the French government: ○: No mineral oil is used ×: Mineral oil is used It was evaluated as follows.

[0101] Rating 5: Continuous printing stability When the inkjet inks of Examples 1 to 6 and Comparative Examples 1 to 10 were used in a JET-HQ510 (piezoelectric drop-on-demand inkjet printer) manufactured by Kishu Giken Kogyo Co., Ltd., high-speed printing (3.5 KHz) was continued for 10 minutes in a 40°C environment. ○: Non-ejecting nozzles are less than 10% ×: Non-ejecting nozzles are 10% or more It was evaluated as follows.

[0102] The results of evaluations 1 to 5 are shown in Tables 1 and 2.

[0103] [Table 1]

[0104] Table 2

Claims

1. A saturated fatty acid monoester (1) having a flash point of 125 to 170°C and a viscosity at 20°C of 4.0 to 10.0 mPa s; A saturated fatty acid monoester (2) having a flash point of 170 to 200°C; and a plasticizer, The plasticizer contains two or more saturated fatty acid diesters having a flash point of 125 to 220°C, or a saturated fatty acid diester having a flash point of 125 to 220°C and a saturated fatty acid monoester (3) having a flash point of 125 to 170°C and a viscosity at 20°C of 0.1 to 4.0 mPa s, and the total content of the saturated fatty acid monoester (1) and the saturated fatty acid monoester (2) is 53.0 to 63.0% by mass, with the total amount of the ink being 100% by mass; Inkjet ink.

2. 2. The ink-jet ink according to claim 1, wherein the ratio of the content of the saturated fatty acid monoester (1) to the content of the saturated fatty acid monoester (2) (saturated fatty acid monoester (2) / saturated fatty acid monoester (1)) is 0.20 to 0.

80.

3. 2. The ink-jet ink according to claim 1, wherein the content of the plasticizer is 15.0 to 35.0% by mass in total, with the total amount of the ink being 100% by mass.

4. The ink-jet ink of claim 1 , further comprising a pigment and / or a dye.

5. The ink-jet ink according to claim 1 , further comprising a pigment derivative and / or a pigment dispersant.

6. The ink-jet ink of claim 1 which is mineral oil-free.

7. The ink-jet ink of claim 1 , which is an oil-based ink-jet ink.

8. The ink-jet ink of claim 1 which is a piezoelectric ink-jet ink.

9. An ink-jet ink container containing the ink-jet ink according to any one of claims 1 to 8.

10. A printed matter, which is printed on a printing substrate with the inkjet ink according to any one of claims 1 to 8.

11. The printed matter according to claim 10, wherein the printing substrate is a porous material.

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