Inkjet composition

Abstract

To provide an ink jet composition capable of reducing nozzle plate detachment and the occurrence of nozzle omission.SOLUTION: There is provided an ink jet composition ejected from an inkjet head, wherein the inkjet head comprises a nozzle plate on which a plurality of nozzles are formed and a channel substrate bonded to one surface of the nozzle plate and in which a channel including a liquid storage chamber for storing a liquid to be supplied to the plurality of nozzles is formed, the liquid storage chamber is formed by a recess provided on a surface opposite to the nozzle plate of the channel substrate and the ink jet composition has a surface tension at 25°C of 31 mN / m or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Liquid jet heads are known that use piezoelectric elements to change the volume of pressure chambers to eject ink from the pressure chambers through nozzles. For example, the head described in Patent Document 1 is formed by bonding a flow path forming member, a communication plate, and a nozzle plate together with an adhesive. However, the head described in Patent Document 1 has many locations where the adhesive-bonded parts come into contact with the ink, and the adhesive at these locations can swell when attacked by the ink, causing the nozzle plate to peel off and resulting in poor head reliability.

[0003] Therefore, for example, as in the head described in Patent Document 2, by forming the area from the nozzle plate to the liquid storage chamber as a single raised flow path substrate, the area where the ink comes into contact with the part joined with adhesive is limited to the vicinity of the nozzle, thereby reducing nozzle plate peeling and improving the reliability of the head. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-55305 [Patent Document 2] Japanese Patent Publication No. 2020-93415 Summary of the Invention [Problem to be solved by the invention]

[0005] However, heads that can reduce nozzle plate peeling have a raised liquid storage chamber, which means that the volume is smaller than that of conventional liquid storage chambers. This results in insufficient pressure to push the ink from the liquid storage chamber into the flow path, which makes nozzles (missing dots) more likely to occur when ejecting ink. [Means for solving the problem]

[0006] One aspect of the inkjet composition according to the present invention is An inkjet composition ejected from an inkjet head, The inkjet head includes a nozzle plate having a plurality of nozzles formed therein; a flow path substrate bonded to one surface of the nozzle plate, the flow path including a liquid storage chamber for storing liquid to be supplied to the plurality of nozzles, the liquid storage chamber is formed by a recess provided on a surface of the flow path substrate opposite to the nozzle plate, The ink jet composition has a surface tension of 31 mN / m or less at 25°C. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a cross-sectional view of an inkjet head used for the inkjet composition according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described. The embodiments described below are examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0009] 1. Inkjet composition An inkjet composition according to one embodiment of the present invention is an inkjet composition ejected from an inkjet head, the inkjet head comprising: a nozzle plate having a plurality of nozzles formed therein; and a flow path substrate bonded to one surface of the nozzle plate and having a flow path formed thereon, the flow path including a liquid storage chamber that stores a liquid to be supplied to the plurality of nozzles, the liquid storage chamber being formed by a recess provided on a surface of the flow path substrate opposite to the nozzle plate; and the inkjet composition has a surface tension of 31 mN / m or less at 25°C.

[0010] The inkjet head used for the inkjet composition according to this embodiment (hereinafter also referred to as the "specific inkjet head") has a raised liquid storage chamber, and therefore tends to have a smaller volume than conventional liquid storage chambers. As a result, there is insufficient pressure to push the ink from the liquid storage chamber into the flow path, and nozzle clogging tends to occur when the ink is ejected.

[0011] Therefore, as a result of intensive research, the present inventors have now found that even when such an inkjet head is used, nozzle dropping can be effectively reduced by adjusting the surface tension of the inkjet composition to a specific value or less. This is presumably because adjusting the surface tension of the inkjet composition to a specific value or less makes it easier for the ink to flow through the flow path.

[0012] In the present invention, the term "inkjet composition" refers to an ink composition that is ejected by an inkjet method. The "inkjet method" is a recording method in which droplets of ink or the like are ejected from the nozzles of an inkjet head of an inkjet recording device or the like and applied to a recording medium. In this specification, the term "inkjet composition" may also be referred to as an "inkjet ink composition," "ink composition," or "ink."

[0013] 1.1 Inkjet head The inkjet composition according to this embodiment is an inkjet composition that is ejected from an inkjet head, and the inkjet head includes a nozzle plate in which a plurality of nozzles are formed, and a flow path substrate that is bonded to one surface of the nozzle plate and in which a flow path is formed, the flow path including a liquid storage chamber that stores liquid to be supplied to the plurality of nozzles, and the liquid storage chamber is formed by a recess provided on the surface of the flow path substrate opposite to the nozzle plate.

[0014] 1.1.1 Overall structure of inkjet head Figure 1 is a cross-sectional view of an inkjet head 26 used for the inkjet composition according to this embodiment. As illustrated in Figure 1, the direction perpendicular to the XY plane will be referred to as the Z direction hereinafter. The direction in which ink is ejected from the inkjet head 26, typically the vertical direction, corresponds to the Z direction. Note that Figure 1 is a cross-sectional view parallel to the XZ plane.

[0015] As illustrated in FIG. 1, the inkjet head 26 comprises a nozzle plate 31, a flow path substrate 32, a vibration plate 33, a case 34, a fixing member 35, and a plurality of piezoelectric elements 36. These are bonded to one another using, for example, an adhesive. The nozzle plate 31 is bonded to the surface of the flow path substrate 32 on the positive side in the Z direction, and the vibration plate 33 is bonded to the surface of the flow path substrate 32 on the negative side in the Z direction. The nozzle plate 31 is a plate-like member in which a plurality of nozzles N arranged in the Y direction are formed. Each nozzle N is a through-hole through which ink passes. The Y direction can also be expressed as the direction in which the plurality of nozzles N are arranged. The nozzle plate 31 is made of a metal material such as stainless steel. For example, the nozzle plate 31 can be manufactured by processing a metal plate by dry etching. The constituent material and manufacturing method of the nozzle plate 31 are not particularly limited and may be any. For example, For example, the nozzle plate 31 may be formed by processing a silicon single crystal substrate using semiconductor manufacturing techniques such as etching.

[0016] The flow path substrate 32 is a plate-like member for forming an ink flow path. As illustrated in FIG. 1 , the flow path substrate 32 is formed with a liquid storage chamber R, a first flow path 324, a pressure chamber C, and a second flow path 326. The liquid storage chamber R is formed by a recess 322 provided on the surface of the flow path substrate 32 on the negative side in the Z direction. The recess 322 is a space recessed with respect to the surface of the flow path substrate 32 on the negative side in the Z direction. The liquid storage chamber R is a common liquid chamber that is continuous across multiple nozzles N. In contrast, the first flow path 324, the second flow path 326, and the pressure chamber C are each formed for each nozzle N. The pressure chamber C is located between the nozzle plate 31 and the vibration plate 33 and is a space for applying pressure to the ink filled in the pressure chamber C. The first flow path 324 is a throttle flow path that connects the pressure chamber C and the liquid storage chamber R. The first flow path 324 is formed by a recess provided on the surface of the flow path substrate 32 on the negative side in the Z direction. The ink stored in the liquid storage chamber R branches off into each of the first flow paths 324 and is supplied in parallel to and fills the multiple pressure chambers C. The second flow paths 326 are formed by through holes that connect the pressure chambers C to the nozzles N. The flow path substrate 32 is formed, for example, by processing a silicon (Si) single crystal substrate using semiconductor manufacturing techniques such as etching.

[0017] In the inkjet head used with the inkjet composition according to this embodiment, the cross-sectional area of ​​the first flow path 324 is preferably smaller than that of the second flow path 326. That is, the flow paths formed in the flow path substrate 32 include the first flow path 324 that delivers the inkjet composition from the liquid storage chamber R and the second flow path 326 that delivers the inkjet composition from the first flow path 324 to the nozzle N, and the cross-sectional area of ​​the first flow path 324 is preferably smaller than that of the second flow path 326. A head with such a configuration can further reduce backflow of ink into the liquid storage chamber R after ink ejection, but requires even greater pressure to push the ink out of the liquid storage chamber R, making nozzle clogging more likely to occur. According to the inkjet composition according to this embodiment, nozzle clogging can be effectively reduced even in a head including the first flow path 324 with such a narrowed cross-sectional area. Note that the cross-sectional area of ​​the first flow path 324 is preferably the cross-sectional area when viewed from the X direction, and the cross-sectional area of ​​the second flow path 326 is preferably the cross-sectional area when viewed from the Z direction. The X direction is also called the "first direction" and the Z direction is called the "second direction."

[0018] The diaphragm 33 is composed of an elastic membrane 331 and a support plate 332. The elastic membrane 331 is bonded to the surface of the flow path substrate 32, and the support plate 332 is laminated on the elastic membrane 331. The elastic membrane 331 is composed of a resin material such as para-aramid resin. The support plate 332 is composed of a metal material such as stainless steel. The support plate 332 has a shape including island-shaped portions 333 that overlap with each pressure chamber C. The support plate 332 is also removed in the area that overlaps with the liquid storage chamber R. Therefore, in this area, the diaphragm 33 is composed of a single layer of the elastic membrane 331, and functions as an elastic compliance film 334. The elastic compliance film 334 forms part of the wall surface that partitions the liquid storage chamber R, and absorbs pressure fluctuations within the liquid storage chamber R.

[0019] The case 34 is a structure manufactured by, for example, injection molding of a resin material, and is joined to the surface of the vibration plate 33 opposite to the flow path substrate 32. As illustrated in FIG. 1, an inlet 341 is formed in the case 34. The inlet 341 is a through-hole that communicates with the liquid storage chamber R described above. The inlet 341 introduces ink from a liquid container (not shown) into the liquid storage chamber R.

[0020] The fixing member 35 is a member for attaching the piezoelectric element 36 to the case 34, and is fixed to the case 34 with adhesive or the like. The piezoelectric element 36 is a longitudinal vibration type driving element in which piezoelectric layers and electrode layers (not shown) are alternately laminated, and the tip portion abuts against the island-shaped portion 333. When the island-shaped portion 333 vibrates together with the elastic film 331 in conjunction with the deformation of the pressure chamber C, the volume of the pressure chamber C changes and ink is ejected from the nozzle N.

[0021] 1.1.2 Liquid Reservoir As illustrated in FIG. 1, the inkjet head 26 includes a nozzle plate 31 in which a plurality of nozzles N are formed, and a flow path substrate 32 in which a flow path including a liquid storage chamber R that stores liquid to be supplied to the plurality of nozzles N is formed, as described above. Here, as illustrated in FIG. 1, the flow path substrate 32 is bonded to one surface of the nozzle plate 31. This bonding is performed using, for example, an adhesive. The adhesive is not particularly limited, but examples include an epoxy-based adhesive and a urethane-based adhesive. The adhesive may include, for example, a filler such as silica or alumina.

[0022] 1, a recess 322 is provided on the surface of the flow path substrate 32 opposite to the nozzle plate 31. This recess 322 forms a liquid storage chamber R. As a result, the adhesive that bonds the nozzle plate 31 and the flow path substrate 32 together is not exposed to the liquid in the liquid storage chamber R, and therefore the adhesive is not deteriorated by the liquid.

[0023] The physical properties of the ink jet composition according to this embodiment and the components contained therein will be described below.

[0024] 1.2 Surface tension of inkjet compositions The inkjet composition according to this embodiment has a surface tension of 31 mN / m or less at 25° C. Preferably, it is 30.5 mN / m or less, more preferably 30 mN / m or less, even more preferably 29.5 mN / m or less, still more preferably 29 mN / m or less, particularly preferably 28.5 mN / m or less, even more particularly preferably 28 mN / m or less, especially preferably 27.5 mN / m or less, even more especially preferably 27 mN / m or less, and especially especially preferably 26.5 mN / m or less. When the surface tension of the inkjet composition at 25° C. is within the above range, nozzle clogging can be effectively reduced even when a specific inkjet head is used.

[0025] An example of a method for measuring surface tension is to use a commonly used surface tensiometer (for example, a surface tensiometer CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) and measure the surface tension by the Wilhelmy method at a liquid temperature of 25°C.

[0026] The surface tension of the ink jet composition can be adjusted by, but not limited to, adjusting the type and content of surfactants and organic solvents that can be contained in the ink.

[0027] 1.3 Surfactants The inkjet composition according to this embodiment preferably contains a surfactant. The surfactant is not particularly limited, but examples thereof include acetylene glycol surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0028] The acetylene glycol surfactant is not particularly limited, but for example, one or more selected from the group consisting of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 2,4-dimethyl-5-decyne-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol are preferred. Commercially available acetylene glycol surfactants are not particularly limited, but for example, the E series, such as Olfin 104 series, Olfin E1010, and E1020 (trade names manufactured by Air Products Japan, Inc.), Surfynol 465, Surfynol 61, and Surfynol D F110D (trade name, manufactured by Nissin Chemical Industry Co., Ltd.) and the like.

[0029] The fluorine-based surfactant is not particularly limited, but examples thereof include perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and perfluoroalkyl amine oxide compound. Commercially available fluorine-based surfactants are not particularly limited, but examples thereof include S-144, S-145 (manufactured by Asahi Glass Co., Ltd.); FC-170C, FC-430, Fluorad-FC4430 (manufactured by Sumitomo 3M Limited); FSO, FSO-100, FSN, FSN-100, FS-300 (manufactured by DuPont); and FT-250, 251 (manufactured by Neos Corporation).

[0030] Examples of silicone surfactants include polysiloxane compounds and polyether-modified organosiloxanes. Commercially available silicone surfactants include, but are not limited to, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, and BYK-349 (all trade names, manufactured by BYK Japan KK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0031] The content of the surfactant is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, even more preferably 0.3 to 2.0% by mass, particularly preferably 0.4 to 1.5% by mass, and even more particularly preferably 0.5 to 1.3% by mass, relative to the ink jet composition. When the content of the surfactant is within the above range, nozzle clogging tends to be more effectively reduced.

[0032] The inkjet composition according to this embodiment may contain one surfactant alone, but preferably contains two or more surfactants. By using a combination of multiple surfactants, it is possible to further reduce the surface tension of the ink compared to when only one surfactant is used, and nozzle clogging tends to be more effectively reduced.

[0033] In particular, it is preferable to contain two or more surfactants with different HLB values, and more preferably, to contain a surfactant with an HLB value of 3 to 8 (hereinafter also referred to as "surfactant A") and a surfactant with an HLB value of 12 to 16 (hereinafter also referred to as "surfactant B").

[0034] Here, the HLB (Hydrophile-Lipophile Balance) value of a surfactant is a value calculated by the Griffin method. Specifically, the HLB value of a surfactant can be calculated according to the following formula (H). HLB value = 20 × (mass % of hydrophilic groups) (H)

[0035] 1.3.1 Surfactant A The inkjet composition according to this embodiment preferably contains a surfactant (surfactant A) having an HLB value of 3 to 8. Surfactant A has high hydrophobicity and excellent defoaming properties. This can reduce the retention, growth, or detachment of air bubbles that may occur on the flow path surface of the inkjet head, and can more effectively reduce nozzle clogging.

[0036] The surfactant A is preferably an acetylene glycol surfactant having an HLB value of 3 to 8. Examples of such surfactants include acetylene glycol surfactants having a main chain carbon number of 10 or more. Examples of surfactants that can be used include alkylene oxide adducts of acetylene glycol. When surfactant A is an acetylene glycol surfactant, being a nonionic surfactant can help the ink to wet and spread evenly over the head member, which can further reduce nozzle clogging.

[0037] The HLB value of surfactant A is preferably 3 to 6, more preferably 3 to 5, and even more preferably 4 to 5. When the HLB value is within the above range, the antifoaming property tends to be more excellent.

[0038] Commercially available surfactants A are not particularly limited, and examples thereof include Surfynol 61 (HLB value: 6), Surfynol 104S (HLB value: 4), Surfynol 104PG50 (HLB value: 4), Surfynol 420 (HLB value: 4), Surfynol 82 (HLB value: 4), Surfynol DF110D (HLB value: 3), Surfynol MD-20 (HLB value: 4), and Surfynol SE-F (HLB value: 6), all manufactured by Nissin Chemical Industry Co., Ltd. These surfactants may be used alone or in combination of two or more.

[0039] The content of surfactant A is preferably 0.01 to 2.0% by mass, more preferably 0.05 to 1.5% by mass, even more preferably 0.1 to 1.0% by mass, particularly preferably 0.15 to 0.7% by mass, and even more particularly preferably 0.2 to 0.4% by mass, relative to the ink jet composition. When the content of surfactant A is within the above range, there is a tendency for nozzle clogging to be more effectively reduced.

[0040] 1.3.2 Surfactant B The inkjet composition according to this embodiment preferably contains a surfactant (surfactant B) with an HLB value of 12 to 16. Surfactant B has high hydrophilicity and excellent wettability. This makes it easier for the ink containing surfactant B to wet and spread over the inkjet head member, and reduces the likelihood of nozzle clogging.

[0041] From the same viewpoint as for surfactant A, surfactant B is preferably an acetylene glycol surfactant having an HLB value of 12 to 16. The HLB value of surfactant B is preferably 12 to 15, more preferably 12 to 14, and even more preferably 13 to 14. When the HLB value is within the above range, wettability tends to be better. When two or more types of surfactant B are used in combination, the HLB value is determined as a weighted average.

[0042] Commercially available surfactants B are not particularly limited, but examples thereof include the E series, such as the Olfin 104 series, Olfin E1010 (HLB value 13), and Olfin E1020 (HLB value 15-16), manufactured by Nissin Chemical Industry Co., Ltd., and Newcol 1006 (HLB value 13.4) and Newcol 1008 (HLB value 14.6), manufactured by Nippon Nyukazai Co., Ltd. These surfactants may be used alone or in combination of two or more.

[0043] The content of surfactant B is preferably 0.1 to 2.0% by mass, more preferably 0.2 to 1.5% by mass, even more preferably 0.3 to 1.0% by mass, and particularly preferably 0.4 to 0.7% by mass, relative to the ink jet composition. When the content of surfactant B is within the above range, there is a tendency for nozzle clogging to be more effectively reduced.

[0044] 1.3.3 Content ratio In the ink jet composition according to this embodiment, the surfactant B is The content of the total mass of the composition is M B The content of surfactant A relative to the total mass of the inkjet composition is M A When the content ratio (M B / M A ) is preferably 1.5 to 4.0, more preferably 1.5 to 3.5, even more preferably 1.5 to 3.0, particularly preferably 1.7 to 2.5, and even more particularly preferably 1.8 to 2.2. Surfactant A is relatively highly hydrophobic, so it is likely to be adsorbed by the adhesive used in the head, which may result in peeling of the nozzle plate. In contrast, surfactant B is relatively highly hydrophilic, so the above problem is unlikely to occur. Therefore, the content ratio (M B / M A ) is within the above range, it is possible to effectively reduce missing nozzles and also to reduce peeling of the nozzle plate.

[0045] 1.4 Organic solvents The inkjet composition according to this embodiment may contain an organic solvent. The organic solvent is preferably a water-soluble organic solvent. The term "water-soluble" refers to a property in which the solubility in 100 g of water at 20°C is 0.1 g or more.

[0046] Examples of organic solvents include esters, alkylene glycol ethers, cyclic esters, nitrogen-containing solvents, alcohols, polyhydric alcohols, etc. Examples of nitrogen-containing solvents include cyclic amides and non-cyclic amides, etc. Examples of non-cyclic amides include alkoxyalkylamides.

[0047] Examples of esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and methoxybutyl acetate; Examples of glycol diesters include ethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0048] The alkylene glycol ethers may be monoethers or diethers of alkylene glycol, and alkyl ethers are preferred. Specific examples include alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether (TEGmBE), tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether, as well as ethylene glycol dimethyl ether and ethylene glycol diethyl ether. alkylene glycol dialkyl ethers such as ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol dimethyl ether.

[0049] Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, as well as compounds in which the hydrogen atom of the methylene group adjacent to the carbonyl group of these cyclic esters is substituted with an alkyl group having 1 to 4 carbon atoms.

[0050] Examples of alkoxyalkylamides include 3-methoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-diethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n-propoxy-N,N-dimethylpropionamide, Examples include N-dimethylpropionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, and 3-tert-butoxy-N,N-methylethylpropionamide.

[0051] Examples of cyclic amides include lactams, such as pyrrolidones such as 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone.

[0052] Examples of alcohols include compounds in which one hydrogen atom of an alkane has been substituted with a hydroxyl group. The alkane preferably has 10 or less carbon atoms, more preferably 6 or less, and even more preferably 3 or less. The alkane has 1 or more carbon atoms, preferably 2 or more. The alkane may be linear or branched. Examples of alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol.

[0053] Polyhydric alcohols have two or more hydroxyl groups in the molecule and can be divided into, for example, alkanediols and polyols.

[0054] Examples of alkanediols include compounds in which an alkane is substituted with two hydroxyl groups. Examples of alkanediols include ethylene glycol (also known as ethane-1,2-diol), propylene glycol (also known as propane-1,2-diol), 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,3-propanediol, 1,3-butylene glycol (also known as 1,3-butanediol), 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2 ,4-pentanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, and the like.

[0055] Examples of polyols include condensates in which two or more molecules of alkanediols are intermolecularly condensed via the hydroxyl groups thereof, and compounds having three or more hydroxyl groups.

[0056] Examples of condensates in which two or more molecules of alkanediols are intermolecularly condensed via the hydroxyl groups thereof include dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylene glycols such as triethylene glycol (standard boiling point 287.4°C) and tripropylene glycol.

[0057] The compound having three or more hydroxyl groups is a compound having an alkane or polyether structure as a backbone and having three or more hydroxyl groups. Examples of the compound having three or more hydroxyl groups include glycerin (normal boiling point 290°C), trimethylolethane, trimethylolpropane, 1,2,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, and polyoxypropylenetriol.

[0058] Alkanediols and polyols can function mainly as penetrating solvents and / or moisturizing solvents, with alkanediols tending to have stronger penetrating solvent properties and polyols tending to have stronger moisturizing solvent properties.

[0059] The organic solvents may be used alone or in combination of two or more.

[0060] The inkjet composition according to this embodiment preferably contains a polyhydric alcohol having a normal boiling point of 270°C or higher. Polyhydric alcohols having a normal boiling point of 270°C or higher have particularly excellent moisturizing properties, which improve the moisturizing properties of the ink and tend to provide better clogging recovery. The normal boiling point of the polyhydric alcohol is more preferably 275°C or higher, even more preferably 280°C or higher, and particularly preferably 285°C or higher.

[0061] Examples of polyhydric alcohols having a normal boiling point of 270° C. or higher include glycerin (normal boiling point 290° C.), triethylene glycol (normal boiling point 287.4° C.), tripropylene glycol (normal boiling point 270° C.), etc. Among these, one or more selected from glycerin and triethylene glycol are preferred.

[0062] The content of the polyhydric alcohol having a normal boiling point of 270°C or more is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, even more preferably 10 to 20% by mass, particularly preferably 12 to 18% by mass, and even more particularly preferably 13 to 16% by mass, based on the total amount of the inkjet composition. When the alcohol content is within the above range, the clogging recovery property tends to be more excellent.

[0063] The content of the organic solvent is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, particularly preferably 15% by mass or more, and even more particularly preferably 20% by mass or more, relative to the total amount of the inkjet composition. The upper limit is also not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, and particularly preferably 30% by mass or less, relative to the total amount of the inkjet composition. When the content of the organic solvent is within the above range, excellent clogging recovery properties may be achieved.

[0064] 1.5 water The inkjet composition according to this embodiment may contain water. The water is not particularly limited, but examples thereof include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water, from which ionic impurities have been removed as much as possible. Furthermore, using water sterilized by ultraviolet irradiation or the addition of hydrogen peroxide can prevent the growth of mold and bacteria when the inkjet composition is stored for a long period of time. This tends to further improve storage stability.

[0065] The water content is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more, relative to the total amount of the inkjet composition. The upper limit of the water content is not particularly limited, but is preferably 90% by mass or less, more preferably 80% by mass or less, relative to the total amount of the inkjet composition.

[0066] 1.6 Colorants The coloring material is not particularly limited, but examples thereof include dyes and pigments. Examples of the dye that can be used include soluble dyes, disperse dyes, and oil-based dyes.

[0067] Examples of water-soluble dyes include CI Acid Yellow 1, 3, 6, 11, 17, 18, 19, 23, 25, 36, 38, 40, 40:1, 42, 44, 49, 59, 59:1, 61, 65, 67, 72, 73, 79, 99, 104, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 219:1, 220, 230, 232, 235, 241, 242, and 246; and CI Acid Orange 3, 7, 8, 10, 19, 22, 24, and 5 1, 51S, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168, CI Acid Red 1, 6, 8, 9, 13, 18, 27, 35, 37, 52, 54, 57, 60, 73, 82, 88, 97, 97:1, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 19 8, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415; CI Acid Violet 17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126; CI Acid Blue 1 , 7, 9, 15, 23, 25, 40, 61:1, 62, 72, 74, 80, 83, 90, 92, 103, 104, 112, 113, 114, 120, 127, 127:1, 128, 129, 138, 140, 142, 156, 158, 171, 182, 185, 193, 199, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 239, 258, 260, 264, 277:1, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339 84, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350; CI Acid Green 9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109; CI Acid Brown 2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413; CI Acid Black 1, 2, Acid dyes such as 3, 24, 24:1, 26, 31, 50, 52, 52:1, 58, 60, 63, 63S, 107, 109, 112, 119, 132, 140, 155, 172, 187, 188, 194, 207, and 222; CI Direct Yellow 8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 86, 87, 98, 105, 106, 130, 137, 142, 147, and 153; CI Direct Orange 6, 26, 27, 34, 39, 40, 46, and 102 , 105, 107, 118; CI Direct Red 2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 254; CI Direct Violet 9, 35, 51, 66, 94, 95; CI Direct Blue 1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 20 1, 202, 203, 218, 225, 229, 237, 244, 248, 251, 270, 273, 274, 290, 291; CI Direct Green 26, 28, 59, 80, 85; CI Direct Brown 44, 44:1, 106, 115, 195, 209, 210, 212:1, 222, 223; CI Direct Black 17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169, and other direct dyes; CIReactive Yellow 2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102, 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160, 161, 165, 167, 168, 175, 176; CI Reactive Orange 1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74 82, 84, 86, 87, 91, 92, 93, 95, 107; CI Reactive Red 2, 3, 3:1, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78, 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190, 193, 194, 19 5, 198, 218, 220, 222, 223, 226, 228, 235; CI Reactive Violet 1, 2, 4, 5, 6, 22, 23, 33, 36, 38; CI Reactive Blue 2, 3, 4, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79, 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 16 Examples of reactive dyes include CI Reactive Green 8, 12, 15, 19, 21; CI Reactive Brown 2, 7, 9, 10, 11, 17, 18, 19, 21, 23, 31, 37, 43, 46; and CI Reactive Black 5, 8, 13, 14, 31, 34, 39.

[0068] Examples of disperse dyes include CI Disperse Yellow 5, 42, 54, 64, 79, 82, 83, 93, 99, 100, 119, 122, 124, 126, 160, 184:1, 186, 198, 199, 204, 224, and 237; CI Disperse Orange 13, 29, and 31:1; CI Disperse Red 54, 60, 72, 73, 86, 88, 91, and 92; 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167:1, 177, 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356, 362; CI Disperse BioRed 33; CI Disperse Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165:1, 165:2, 176, 183, 185, 197, 198, 201, 214, 224, 225, 257, 266, 267, 287, 354, 358, 365, 368; CI Disperse Green 6:1, 9, etc.

[0069] Examples of oil-based dyes include CI Solvent Black 3, 7, 27, 29, and 34; CI Solvent Yellow 14, 16, 19, 29, 56, and 82; CI Solvent Red 1, 3, 8, 18, 24, 27, 43, 51, 72, 73, 132, and 218; CI Solvent Violet 3; CI Solvent Blue 2, 11, and 70; CI Solvent Green 3 and 7; and CI Solvent Orange 2.

[0070] Examples of pigments that can be used include various organic and inorganic pigments, such as azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments, polycyclic pigments such as phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxandine pigments, thioindigo pigments, isoindolinone pigments, and quinophthaloni pigments, dye lakes such as basic dye lakes and acid dye lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments, and inorganic pigments such as carbon black.

[0071] The content of the colorant can be adjusted appropriately depending on the application, but is preferably 0.1% by mass or more and 17.0% by mass or less, more preferably 0.2% by mass or more and 15.0% by mass or less, even more preferably 1.0% by mass or more and 10.0% by mass or less, and particularly preferably 2.0% by mass or more and 5.0% by mass or less, relative to the total amount of the inkjet composition. When the content of the colorant is within the above range, the ejection performance of the head may be better.

[0072] 1.7 pH adjuster The inkjet composition according to this embodiment may contain a pH adjuster. The pH adjuster is not particularly limited, but examples thereof include organic bases and inorganic bases. Examples of organic bases include alkanolamines such as triethanolamine, diethanolamine, monoethanolamine, and tri-isopropanolamine. Examples of inorganic bases that can be used include strong bases such as hydroxides of alkali metals or alkaline earth metals, such as lithium hydroxide, potassium hydroxide, and calcium hydroxide.

[0073] When a pH adjuster is contained in the inkjet composition, the content thereof is preferably 0.01 to 1.0 mass %, more preferably 0.03 to 0.5 mass %, even more preferably 0.05 to 0.3 mass %, and particularly preferably 0.07 to 0.15 mass %, relative to the total amount of the inkjet composition. When the content of the pH adjuster is within the above range, the dispersion stability of the colorant is improved, and the ejection performance of the head may be further improved.

[0074] 1.8 Other ingredients The inkjet composition according to this embodiment may contain various additives as appropriate, such as resins, dispersants, preservatives, antifungal agents, chelating agents, waxes, softeners, dissolution aids, viscosity modifiers, and antioxidants, in addition to the components described above.

[0075] 2. Working Example The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" below is based on mass.

[0076] 2.1 Preparation of inkjet composition The components were placed in a container to obtain the composition shown in Table 1 below, and mixed and stirred for 2 hours using a magnetic stirrer. After that, the mixture was dispersed in a bead mill filled with zirconia beads having a diameter of 0.3 mm, resulting in thorough mixing. After stirring for 1 hour, the mixture was filtered using a 5 μm PTFE membrane filter to obtain inkjet compositions according to each example and comparative example. Pure water was added so that the total amount of the inkjet composition was 100% by mass.

[0077] [Table 1]

[0078] The following is a supplementary explanation of the descriptions in Table 1 above. Inkjet head In the table, "X" indicates the inkjet head shown in Figure 1. Also, in the table, "Y" indicates the inkjet head shown in Figure 10 of JP2020-55305A. The term "specific structure" refers to a structure in which an inkjet head comprises a nozzle plate in which a plurality of nozzles are formed, and a flow path substrate bonded to one surface of the nozzle plate and in which a flow path including a liquid storage chamber for storing liquid to be supplied to the plurality of nozzles is formed, and the liquid storage chamber is formed by a recess provided on the surface of the flow path substrate opposite the nozzle plate.

[0079] <Ink ingredients> [Colorant] DB199 (CI Direct Blue 199) [Surfactant] Surfynol DF110D (product name of Nissin Chemical Industry Co., Ltd., acetylene glycol surfactant) Surfynol 104PG50 (product name of Nissin Chemical Industry Co., Ltd., acetylene glycol surfactant) Surfynol SE-F (product name of Nissin Chemical Industry Co., Ltd., acetylene glycol surfactant) Olfine E1010 (trade name of Air Products, acetylene glycol surfactant) Olfine E1020 (trade name of Air Products, acetylene glycol surfactant) 〔others〕 TEGmBE (triethylene glycol monobutyl ether)

[0080] <surface tension> The surface tension of the ink was measured by checking the surface tension when a platinum plate was wetted with the ink in an environment of 25°C using an automatic surface tensiometer CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.).

[0081] 2.2 Evaluation method 2.2.1 NP (Nozzle Plate) Peeling (Attack on the Head) Inkjet head X or inkjet head Y was immersed in the inkjet composition obtained above and left to stand at 80° C. for 65 hours, after which the degree of adhesive peeling was visually observed and evaluated according to the following criteria. (judgment criteria) A: No ink penetration into the adhesive B: There is some ink erosion in corners and other areas with large contact surfaces. C: Overall ink erosion but in good condition

[0082] 2.2.2 Dead pixels The inkjet composition obtained above was filled into an inkjet printer (a modified version of the product name "PX-G930", manufactured by Seiko Epson Corporation) that had been modified to include the inkjet head described in Table 1 above, and 3,000 sheets were printed continuously, followed by evaluation according to the following criteria. (judgment criteria) A: No missing dots during 3,000 prints B: Missing dots occur during the 3,000 prints, but are recovered by CL (cleaning) and printing can be continued without problems thereafter. C: Missing dots occur after printing 3,000 sheets, and although they are temporarily corrected by CL (cleaning), the missing dots recur.

[0083] 2.2.3 Clogging recovery The inkjet composition obtained above was filled into an inkjet printer (a modified version of the product name "PX-G930", manufactured by Seiko Epson Corporation) modified to include the inkjet head shown in Table 1 above, and the printer was left for 7 days with the ink cartridge cap open in an environment of a temperature of 40°C and a humidity of 25%. After that, printing of a nozzle check pattern and cleaning (CL) were repeatedly performed, and evaluation was performed according to the following criteria. (judgment criteria) A: Full recovery within 3 CLs B: Full recovery after 4 or more CLs

[0084] 2.3 Evaluation results The evaluation results are shown in Table 1 above.

[0085] As can be seen from Table 1 above, an inkjet composition is ejected from an inkjet head, the inkjet head comprising a nozzle plate having a plurality of nozzles formed therein, and a flow path substrate joined to one surface of the nozzle plate and having a flow path formed thereon, the flow path including a liquid storage chamber that stores a liquid to be supplied to the plurality of nozzles, the liquid storage chamber being formed by a recess provided on the surface of the flow path substrate opposite to the nozzle plate, the inkjet composition having a surface tension of 31 mN / m or less at 25°C, and all of the inkjet compositions in each example were able to effectively reduce nozzle plate peeling and nozzle missing.

[0086] Comparing each example with comparative examples 1 and 2, it was found that the use of an inkjet head with a specific structure successfully reduced the peeling of the nozzle plate.

[0087] Comparing each example with Comparative Example 3, it was found that when the surface tension of the ink was 31 mN / m or less, the occurrence of missing nozzles could be effectively reduced.

[0088] The following can be derived from the above-described embodiment.

[0089] One embodiment of the inkjet composition comprises: An inkjet composition ejected from an inkjet head, The inkjet head includes a nozzle plate having a plurality of nozzles formed therein; a flow path substrate bonded to one surface of the nozzle plate, the flow path including a liquid storage chamber for storing liquid to be supplied to the plurality of nozzles, the liquid storage chamber is formed by a recess provided on a surface of the flow path substrate opposite to the nozzle plate, The ink jet composition has a surface tension of 31 mN / m or less at 25°C.

[0090] In one embodiment of the inkjet composition, The inkjet composition may contain two or more surfactants.

[0091] In any of the above inkjet compositions, The surfactant may include surfactant A having an HLB value of 3 to 8.

[0092] In any of the above inkjet compositions, The surfactant may include surfactant B having an HLB value of 12 to 16.

[0093] In any of the above inkjet compositions, The content of the surfactant B relative to the total mass of the inkjet composition is M B The content of the surfactant A relative to the total mass of the inkjet composition is M A When the content ratio (M B / M A ) may be 1.5 to 4.0.

[0094] In any of the above inkjet compositions, The inkjet composition may contain a polyhydric alcohol having a normal boiling point of 270° C. or higher.

[0095] In any of the above inkjet compositions, the flow path includes a first flow path that delivers the ink jet composition from the liquid storage chamber, and a second flow path that delivers the ink jet composition from the first flow path to the nozzle, The cross-sectional area of ​​the first flow path may be smaller than the cross-sectional area of ​​the second flow path.

[0096] 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, such as configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0097] 26...inkjet head, 31...nozzle plate, 32...flow path substrate, 322...recess, 324...first flow path, 326...second flow path, 33...vibration plate, 331...elastic membrane, 332...support plate, 333...island-shaped portion, 334...elastic compliance film, 34...case, 341...inlet, 35...fixing member, 36...piezoelectric element, C...pressure chamber, N...nozzle, R...liquid storage chamber.

Claims

1. An inkjet composition ejected from an inkjet head, The inkjet head includes a nozzle plate having a plurality of nozzles formed therein; a flow path substrate bonded to one surface of the nozzle plate, the flow path including a liquid storage chamber for storing liquid to be supplied to the plurality of nozzles, the liquid storage chamber is formed by a recess provided on a surface of the flow path substrate opposite to the nozzle plate, the inkjet composition has a surface tension of 31 mN / m or less at 25°C; The inkjet composition contains two or more surfactants, The surfactants include surfactant A having an HLB value of 3 to 8 and surfactant B having an HLB value of 12 to 16, The inkjet composition, wherein the content ratio (M B / M A ) is 1.5 to 2.5, where M B is the content of the surfactant B relative to the total mass of the inkjet composition and M A is the content of the surfactant A relative to the total mass of the inkjet composition.

2. An inkjet composition as described in claim 1, wherein the HLB value of the surfactant A is 4 to 5.

3. An inkjet composition described in claim 1 or claim 2, wherein the HLB value of the surfactant B is 12 to 14.

4. The content of the surfactant B relative to the total mass of the inkjet composition is M Ｂ The content of the surfactant A relative to the total mass of the ink jet composition is M Ａ When the content ratio (M Ｂ / M Ａ 4. The ink jet composition according to claim 1, wherein the saturation coefficient (μm) is 1.5 to 2.

2.

5. The inkjet composition according to claim 1 , further comprising a polyhydric alcohol having a normal boiling point of 270° C. or higher.

6. the flow path includes a first flow path that delivers the ink jet composition from the liquid storage chamber and a second flow path that delivers the ink jet composition from the first flow path to the nozzle, The ink jet composition according to claim 1 , wherein a cross-sectional area of ​​the first flow path is smaller than a cross-sectional area of ​​the second flow path.

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