Liquid discharge structure, liquid discharge head, liquid discharge apparatus, method for manufacturing liquid discharge structure, and laminate

Abstract

The invention provides a liquid ejection structure, a liquid ejection head, and a liquid ejection apparatus, wherein the ejection surface of the liquid ejection structure has excellent wiping resistance. A liquid discharge structure is provided with a nozzle substrate in which a nozzle for discharging a liquid is formed, and has a liquid-repellent layer on a discharge surface of the nozzle substrate, and the liquid-repellent layer contains a compound having a hydrocarbon group having 8 or more carbon atoms.

Description

Technical Field

[0001] The present invention relates to a liquid discharge structure, a liquid discharge head, a liquid discharge device, a method for manufacturing the liquid discharge structure, and a laminate. Background Art

[0002] Typically, a liquid ejection head, typically an inkjet head mounted on an inkjet recording device, has a nozzle for ejecting liquid. Liquid is supplied from a liquid supply chamber to a liquid flow path and ejected from a nozzle hole formed in the nozzle connected to the liquid flow path.

[0003] For example, Patent Document 1 describes a nozzle plate comprising: a silicon substrate having a nozzle formed thereon; a first organic film formed on the silicon substrate and containing no fluorine atoms; an inorganic oxide film formed on the first organic film; and a second organic film formed on the inorganic oxide film and made of a linear fluorosilane coupling agent.

[0004] Patent document 2 describes a liquid-repellent treatment method for imparting liquid-repellency to the surface of a substrate having a pore portion, and is characterized in that it includes: an organic film forming process for forming an organic film on the surface of the substrate and the inner wall surface of the pore portion; a protective component forming process for forming a protective component on the organic film on the surface of the substrate; an organic film removing process for removing the organic film on the inner wall surface of the pore portion of the substrate; a protective component removing process for removing the protective component on the organic film on the surface of the substrate; and a fluorination treatment process for fluorinating the organic film on the surface of the substrate.

[0005] Patent document 3 describes a liquid ejection structure comprising a nozzle substrate having a nozzle for ejecting liquid and a flow path substrate having a liquid flow path connected to the nozzle, wherein a first layer, a second layer, and a liquid-repellent layer are sequentially provided on the ejection surface of the nozzle substrate, and the first layer and the second layer are sequentially provided on the inner wall of the liquid flow path, wherein the first layer is a layer comprising at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide, and the second layer is a layer comprising at least one selected from the group consisting of SiO2, SiC, SiN, SiCN, and SiON, wherein the liquid-repellent layer comprises a compound having a perfluoropolyether structure.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-166747

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-214654

[0008] Patent Document 3: International Publication No. 2021 / 199731

[0009] Since the liquid dries after being ejected, the components contained in the liquid adhere to the ejection surface of the liquid ejection head as foreign matter. If foreign matter adheres to the nozzle surface, poor ejection is likely to occur. Therefore, in the liquid ejection device, foreign matter can be removed by regularly wiping the ejection surface of the liquid ejection head. However, wiping sometimes reduces the durability of the ejection surface of the liquid ejection head, and durability to wiping (hereinafter also referred to as "wipe resistance") is required. Summary of the Invention

[0010] The present invention has been made in view of such circumstances, and an embodiment of the present invention aims to provide a liquid discharge structure, a liquid discharge head, and a liquid discharge device having a discharge surface with excellent wiping resistance.

[0011] Another embodiment of the present invention aims to provide a laminate useful in a liquid discharge structure having an excellent wiping resistance on a discharge surface.

[0012] The present invention includes the following aspects.

[0013] <1>

[0014] A liquid discharge structure includes a nozzle substrate on which a nozzle for discharging liquid is formed.

[0015] The nozzle substrate has a liquid-repellent layer on the discharge surface.

[0016] The liquid-repellent layer contains a compound having a hydrocarbon group having 8 or more carbon atoms.

[0017] <2>

[0018] The liquid discharge structure according to <1>, wherein:

[0019] The compound having a hydrocarbon group having 8 or more carbon atoms has a partial structure represented by the following formula (1).

[0020] LYM-*…(1)

[0021] In formula (1),

[0022] L is a hydrocarbon group having 8 or more carbon atoms,

[0023] Y is a single bond or a divalent linking group,

[0024] M is a semimetal or metal,

[0025] *Indicates bonding position to other structures.

[0026] <3>

[0027] The liquid discharge structure according to <1> or <2>, wherein:

[0028] The hydrocarbon group having 8 or more carbon atoms is a linear alkyl group having 8 or more carbon atoms.

[0029] <4>

[0030] The liquid discharge structure according to <2>, wherein:

[0031] In formula (1), Y is a single bond.

[0032] <5>

[0033] The liquid discharge structure according to any one of <1> to <4>, wherein

[0034] An intermediate layer and a liquid-repellent layer are sequentially provided on the ejection surface of the nozzle substrate.

[0035] <6>

[0036] The liquid discharge structure according to any one of <1> to <5>, wherein

[0037] The intermediate layer is a layer including at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, hafnium oxide, SiO 2 , SiC, SiN, SiCN, and SiON.

[0038] <7>

[0039] The liquid discharge structure according to <5>, wherein:

[0040] The middle layer consists of 2 layers.

[0041] The discharge surface has a first intermediate layer, a second intermediate layer, and a liquid-repellent layer in this order.

[0042] <8>

[0043] The liquid discharge structure according to <7>, wherein:

[0044] The first intermediate layer is a layer containing at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide.

[0045] The second intermediate layer is a layer containing at least one selected from the group consisting of SiO 2 , SiC, SiN, SiCN, and SiON.

[0046] <9>

[0047] A liquid ejection head includes: the liquid ejection structure according to any one of <1> to <8>; and a flow path substrate having a liquid flow path formed thereon and communicating with a nozzle.

[0048] <10>

[0049] The liquid ejection head according to <9>, further comprising a piezoelectric element.

[0050] <11>

[0051] A liquid discharge device comprises: the liquid discharge head described in <9>; a conveying mechanism for conveying a substrate; and a drying mechanism for drying the liquid discharged onto the substrate.

[0052] <12>

[0053] A method for manufacturing a liquid discharge structure comprises forming a liquid-repellent layer by vapor deposition using a liquid-repellent layer-forming composition containing a compound having a hydrocarbon group having 8 or more carbon atoms on a discharge surface of a nozzle substrate having a nozzle for discharging liquid.

[0054] <13>

[0055] A laminate comprising:

[0056] substrate; and

[0057] The liquid-repellent layer is disposed on the substrate.

[0058] The liquid-repellent layer contains a compound having a hydrocarbon group having 8 or more carbon atoms.

[0059] Effects of the Invention

[0060] According to one embodiment of the present invention, there are provided a liquid discharge structure having a discharge surface with excellent wiping resistance, a liquid discharge head, a liquid discharge device, and a method for manufacturing the liquid discharge structure.

[0061] According to another embodiment of the present invention, there is provided a laminate useful in a liquid discharge structure having an excellent wiping resistance on a discharge surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a schematic cross-sectional view showing one embodiment of the liquid ejection head of the present invention.

[0063] Figure 2 yes Figure 1 Enlarged view of the dotted box A in FIG.

[0064] Figure 3 It is a diagram showing a modified example of the intermediate layer.

[0065] Figure 4 This is a schematic cross-sectional view showing a modified example of the liquid ejection head of the present invention.

[0066] Figure 5 This is a schematic cross-sectional view showing another embodiment of the liquid ejection head of the present invention. DETAILED DESCRIPTION

[0067] Hereinafter, the liquid discharge structure, the liquid discharge head, the liquid discharge device, the method for manufacturing the liquid discharge structure, and the laminated body according to the present invention will be described in detail.

[0068] In the present invention, a numerical range expressed using “to” means a range including the numerical values described before and after “to” as the lower limit and the upper limit.

[0069] In the present invention, when the composition contains a plurality of substances corresponding to the components, the amount of each component in the composition refers to the total amount of the plurality of substances present in the composition unless otherwise specified.

[0070] In the numerical ranges described in stages in the present invention, the upper limit or lower limit described in a certain numerical range may be replaced by the upper limit or lower limit of another numerical range described in stages, or may be replaced by the value shown in the Examples.

[0071] In the present invention, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0072] In the present invention, a combination of preferred embodiments is a more preferred embodiment.

[0073] The elements in the drawings shown in the present invention are not necessarily to exact scale, but emphasis is placed on clearly illustrating the principles of the present invention, and some areas are emphasized.

[0074] In the present invention, a "lyophobic layer" refers to a layer having a contact angle with water of 60° or greater. The contact angle with water is a value measured at 25°C using a contact angle meter, such as a fully automatic contact angle meter (product name "DM-701", manufactured by Kyowa Interface Science Co., Ltd.).

[0075] In the present invention, the "discharge surface" refers to the surface of the nozzle substrate on the side where the liquid is discharged in the liquid discharge structure.

[0076] In the present invention, the "inner wall of the liquid flow path" refers to the surface of the flow path substrate on which the liquid flow path is formed. Also, the "inner wall of the nozzle" refers to the surface of the nozzle substrate on which the nozzle is formed.

[0077] [Liquid discharging structure]

[0078] The liquid discharge structure of the present invention includes a nozzle substrate having a nozzle for discharging liquid formed thereon, and a liquid-repellent layer on a discharge surface of the nozzle substrate. The liquid-repellent layer includes a compound having a hydrocarbon group having 8 or more carbon atoms.

[0079] The liquid-repellent layer is located on the outermost surface of the nozzle substrate. Specifically, the liquid-repellent layer is the outermost layer of the multiple layers provided on the nozzle substrate. The liquid ejection structure of the present invention has excellent anti-fouling properties on the ejection surface due to the liquid-repellent layer being located on the outermost surface of the nozzle substrate.

[0080] In particular, the liquid discharge structure of the present invention has excellent wiping resistance on the discharge surface because the liquid-repellent layer contains a compound having a hydrocarbon group with 8 or more carbon atoms. This is believed to be because the durability of the liquid-repellent layer is enhanced by the aggregation of the hydrocarbon groups with 8 or more carbon atoms.

[0081] In contrast, the liquid-repellent layers described in Patent Documents 1 to 3 are all fluorine-based liquid-repellent layers, and there is no description focusing on a liquid-repellent layer containing a compound having a hydrocarbon group having 8 or more carbon atoms.

[0082] Hereinafter, one embodiment of the liquid ejection structure of the present invention will be described with reference to the drawings showing one embodiment of the liquid ejection head of the present invention.

[0083] Figure 1 This is a cross-sectional view showing one embodiment of the liquid ejection head of the present invention.

[0084] like Figure 1 As shown, the liquid ejection head 100 includes a liquid ejection structure having a nozzle substrate 10 formed with nozzles 30 for ejecting liquid, and a flow path substrate 20 formed with liquid flow paths 40 communicating with the nozzles 30. The nozzle substrate 10 and the flow path substrate 20 are preferably joined by bonding or the like.

[0085] In the present invention, the liquid ejection structure refers to a structure including a nozzle substrate 10 on which nozzles 30 for ejecting liquid are formed and a liquid-repellent layer described later. That is, the liquid ejection structure is a part of the liquid ejection head.

[0086] The type of liquid supplied to the liquid ejection head 100 is not particularly limited. The liquid ejection head 100 is assembled into a liquid ejection device described below, thereby ejecting fine liquid droplets from the nozzle 30. Ink is preferably used as the liquid, and an image can be recorded by ejecting fine ink droplets onto a substrate.

[0087] The ink used to record an image is a liquid containing, for example, a colorant, a solvent, and a surfactant. Furthermore, a pre-treatment liquid may be discharged onto the substrate before the ink is discharged onto the substrate, or a post-treatment liquid may be discharged after the ink is discharged. Therefore, in addition to the ink, the liquid supplied to the liquid discharge head 100 also includes a pre-treatment liquid and a post-treatment liquid. These pre-treatment liquids are typically colorless liquids that do not contain a colorant.

[0088] Furthermore, the liquid supplied to the liquid discharge head 100 can be either an acidic liquid or an alkaline liquid. The liquid discharge head 100 is suitable for alkaline liquids due to the excellent alkali resistance of the discharge surface and the interior of the flow path. In particular, the liquid discharge head 100 is suitable for liquids with a pH of 8 to 11. The pH is a value measured at 25°C using a pH meter, for example, a "Handy-type pH meter" manufactured by SATO KEIRYOKIMFG.CO.,LTD.

[0089] <Nozzle substrate>

[0090] The nozzle substrate 10 is a substrate made of silicon, for example, and may be a single crystal silicon substrate or a polycrystalline silicon substrate. A nozzle 30 for discharging liquid is formed on the nozzle substrate 10 .

[0091] The nozzle 30 is a hole that passes through the nozzle substrate 10 and is formed, for example, by dry etching. A plurality of nozzles 30 are preferably formed on the nozzle substrate 10. The shape of the nozzle 30 is not particularly limited, but from the perspective of controlling the direction in which the liquid is ejected, it is preferably a tapered shape with a diameter that decreases toward the direction in which the liquid is ejected. The aperture of the nozzle 30 on the side from which the liquid is ejected, that is, the aperture of the nozzle opening 31, can be adjusted appropriately. When the liquid ejection head 100 is used in an inkjet head, the aperture of the nozzle opening 31 is, for example, 10 μm to 30 μm.

[0092] The thickness of the nozzle substrate 10 corresponds to the length of the nozzle 30 , and is preferably 10 μm to 100 μm, and more preferably 20 μm to 60 μm.

[0093] Figure 2 yes Figure 1 Enlarged view of the dotted box A in FIG.

[0094] like Figure 2 As shown, an intermediate layer 51 and a liquid-repellent layer 52 are sequentially provided on the ejection surface 101 of the nozzle substrate 10 .

[0095] If the intermediate layer 51 is included between the nozzle substrate and the liquid-repellent layer, corrosion of the nozzle substrate 10 due to degradation of the liquid-repellent layer 52 can be suppressed.

[0096] The intermediate layer 51 is preferably a layer including at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, hafnium oxide, SiO 2 , SiC, SiN, SiCN, and SiON.

[0097] At least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide (preferably tantalum oxide, zirconium oxide, or hafnium oxide) has excellent alkali resistance. Therefore, even if alkaline liquid permeates the liquid-repellent layer 52 provided on the discharge surface of the nozzle substrate due to long-term use, the presence of the intermediate layer 51 can maintain the alkali resistance of the discharge surface.

[0098] The layer containing at least one selected from the group consisting of SiO2, SiC, SiN, SiCN, and SiON (preferably the SiO2 layer) has high adhesion to the liquid-repellent layer 52. Therefore, alkaline liquids are unlikely to penetrate the liquid-repellent layer 52, and the discharge surface has excellent alkali resistance.

[0099] The thickness of the intermediate layer 51 is preferably 0.3 nm to 100 nm, and more preferably 0.5 nm to 50 nm.

[0100] When the thickness of the intermediate layer 51 is 100 nm or less, the stress of the film does not become excessive, and cracks are less likely to occur.

[0101] When the thickness of the intermediate layer 51 is 0.3 nm or more, the film tends to become uniform, and the adhesion with the liquid-repellent layer is improved.

[0102] From the perspective of further improving the abrasion resistance and alkali resistance of the discharge surface, Figure 3 As shown, the intermediate layer 51 is composed of two layers, and preferably includes a first intermediate layer 51A, a second intermediate layer 51B, and a liquid-repellent layer 52 in this order on the ejection surface 101 of the nozzle substrate 10 .

[0103] The first intermediate layer 51A is preferably a layer including at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide, and more preferably a layer including tantalum oxide, zirconium oxide, or hafnium oxide.

[0104] At least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide (preferably tantalum oxide, zirconium oxide, or hafnium oxide) has excellent alkali resistance. Therefore, even if alkaline liquid permeates the liquid-repellent layer 52 and the second intermediate layer 51B provided on the discharge surface of the nozzle substrate due to long-term use, the presence of the first intermediate layer 51A can maintain the alkali resistance of the discharge surface.

[0105] The thickness of the first intermediate layer 51A is preferably 3 nm to 70 nm, more preferably 10 nm to 50 nm, and even more preferably 20 nm to 50 nm. If the thickness of the first intermediate layer 51A is 3 nm or greater, alkaline liquids are less likely to penetrate, and the abrasion resistance and alkali resistance of the ejection surface are improved. On the other hand, if the thickness of the first intermediate layer 51A is 70 nm or less, defects are less likely to form within the layer, and the abrasion resistance and alkali resistance of the ejection surface are improved. In addition, from the perspective of productivity, the thickness of the first intermediate layer 51A is preferably 50 nm or less.

[0106] The second intermediate layer 51B is preferably a layer including at least one selected from the group consisting of SiO 2 , SiC, SiN, SiCN, and SiON, and is more preferably a SiO 2 layer.

[0107] The layer comprising at least one selected from the group consisting of SiO2, SiC, SiN, SiCN, and SiON (preferably the SiO2 layer) has high adhesion to the liquid-repellent layer 52. Therefore, alkaline liquids are less likely to penetrate the liquid-repellent layer 52 and the second intermediate layer 51B, and the discharge surface has excellent abrasion resistance and alkali resistance.

[0108] The thickness of the second intermediate layer 51B is preferably 0.3 nm to 120 nm, more preferably 0.3 nm to 3 nm or 10 nm to 100 nm, further preferably 0.3 nm to 3 nm, and particularly preferably 0.5 nm to 2 nm. In particular, when the thickness of the second intermediate layer 51B is 0.3 nm to 3 nm or 10 nm to 100 nm, the adhesion between the second intermediate layer 51B and the liquid-repellent layer 52 is improved, and the abrasion resistance and alkali resistance of the discharge surface are further improved.

[0109] The liquid-repellent layer 52 preferably has a contact angle with water of 60° or greater. The contact angle with water of the liquid-repellent layer 52 is more preferably 70° or greater, and even more preferably 80° or greater. Since the liquid-repellent layer 52 is provided on the outermost surface of the nozzle substrate 10, the discharge surface exhibits excellent wiping resistance.

[0110] The liquid-repellent layer 52 contains a compound having a hydrocarbon group having 8 or more carbon atoms (hereinafter also referred to as a “specific compound”).

[0111] When the number of carbon atoms of the hydrocarbon group contained in the specific compound is 8 or more, the hydrocarbon groups aggregate with each other, thereby improving the durability of the liquid-repellent layer.

[0112] From the viewpoint of improving the durability of the liquid-repellent layer by further agglomerating the hydrocarbon groups, the number of carbon atoms in the hydrocarbon group contained in the specific compound is preferably 10 or more, more preferably 18 or more. The upper limit of the number of carbon atoms is not particularly limited, but from the viewpoint of easy film formation, it is preferably 40 or less, more preferably 30 or less, and even more preferably 22 or less.

[0113] The hydrocarbon group contained in the specific compound may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0114] Furthermore, the hydrocarbon group may be a monovalent hydrocarbon group or a divalent hydrocarbon group.

[0115] Among them, the hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably an alkyl group. The alkyl group may be any of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group.

[0116] From the viewpoint of improving the durability of the liquid-repellent layer by further agglomerating the hydrocarbon groups, the hydrocarbon group having 8 or more carbon atoms is preferably a linear alkyl group having 8 or more carbon atoms.

[0117] The specific compound has a hydrocarbon group having 8 or more carbon atoms. The structure other than the hydrocarbon group having 8 or more carbon atoms is not particularly limited, but preferably contains a silicon atom from the viewpoint of liquid repellency.

[0118] Specifically, the specific compound preferably has a partial structure represented by the following formula (1).

[0119] LYM-*…(1)

[0120] In formula (1),

[0121] L is a hydrocarbon group having 8 or more carbon atoms.

[0122] Y is a single bond or a divalent linking group.

[0123] M is a semimetal or metal,

[0124] *Indicates bonding position to other structures.

[0125] Preferred embodiments of the hydrocarbon group having 8 or more carbon atoms represented by L are as described above.

[0126] Examples of the divalent linking group represented by Y include a combination of at least one selected from the group consisting of -O-, -C(=O)-, and -NR-, and a hydrocarbon group.

[0127] R represents a hydrogen atom or a hydrocarbon group.

[0128] The linking portion between Y and L is not a hydrocarbon group.

[0129] When Y is a divalent linking group, examples of Y include

[0130] * 1 -OC(=O)-(alkyl)-C(=O)-O-(alkyl)-* 2

[0131] * 1 -O-(alkyl)-O-(alkyl)-* 2

[0132] * 1 -C(=O)-NH-(alkyl)-* 2

[0133] * 1 -NH-C(=O)-NH-(alkyl)-* 2

[0134] * 1 -OC(=O)-NH-(alkyl)-* 2 .

[0135] * 1Indicates the bonding position with L, * 2 Indicates the bonding position with M.

[0136] The hydrocarbon group contained in the divalent linking group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0137] Among them, the hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably an alkylene group. The alkylene group may be any of a linear alkylene group, a branched alkylene group, and a cyclic alkylene group, but is preferably a linear alkylene group.

[0138] From the viewpoint of improving the durability of the liquid-repellent layer by further agglomerating the hydrocarbon groups, Y is preferably a single bond.

[0139] Examples of M include Si, Al, and Ti.

[0140] Among them, M is preferably Si.

[0141] The liquid-repellent layer 52 is preferably formed using a compound represented by the following formula (2).

[0142] LYX…(2)

[0143] In formula (2),

[0144] L is a hydrocarbon group having 8 or more carbon atoms.

[0145] Y is a single bond or a divalent linking group.

[0146] X is a group capable of chemically bonding to the intermediate layer.

[0147] Preferred embodiments of the hydrocarbon group having 8 or more carbon atoms represented by L are as described above.

[0148] Preferred embodiments of the divalent linking group represented by Y are as described above. Y is preferably a single bond.

[0149] Examples of X include a hydrolyzable silyl group.

[0150] The hydrolyzable silyl group is a group having a silicon atom and a hydrolyzable group directly bonded to the silicon atom.

[0151] Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group. The hydrolyzable group is preferably a halogen atom or an alkoxy group, and more preferably an alkoxy group.

[0152] Examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferred.

[0153] The alkoxy group is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 3 carbon atoms.

[0154] When the hydrolyzable group is an alkoxy group, the density of the liquid-repellent layer 52 is improved, and the alkali resistance is improved.

[0155] In particular, the liquid-repellent layer 52 is preferably formed using a compound represented by the following formula (2A).

[0156] LY-Si(X 1 )3…(2A)

[0157] In formula (2A),

[0158] L is a hydrocarbon group having 8 or more carbon atoms.

[0159] Y is a single bond or a divalent linking group.

[0160] X 1 are each independently a halogen atom or an alkoxy group.

[0161] Preferred embodiments of the hydrocarbon group having 8 or more carbon atoms represented by L are as described above.

[0162] Preferred embodiments of the divalent linking group represented by Y are as described above. Y is preferably a single bond.

[0163] By X 1 Preferred embodiments of the halogen atom and alkoxy group represented by are as described above.

[0164] From the perspective of easy availability, 3 Xs are preferred. 1 same.

[0165] For example, by using a compound represented by formula (2A), the liquid-repellent layer 52 including a compound having a partial structure represented by formula (1) can be obtained.

[0166] The liquid-repellent layer 52 may contain a hydrolyzate of the compound represented by formula (2A).

[0167] The hydrolyzate of the compound represented by formula (2A) has Si—O—Si bonds, and furthermore, the durability of the liquid-repellent layer 52 is improved due to the aggregation of hydrocarbon groups having 8 or more carbon atoms.

[0168] The thickness of the liquid-repellent layer 52 is preferably 0.5 nm to 10 nm, more preferably 1 nm to 3 nm. When the thickness of the liquid-repellent layer 52 is 3 nm or less, the scratch resistance is improved.

[0169] like Figure 1 and Figure 2 As shown, the liquid ejection head 100 includes an intermediate layer 51 on the inner wall 102 of the nozzle 30. The intermediate layer 51 provided on the inner wall 102 of the nozzle 30 is the same as the intermediate layer 51 provided on the ejection surface 101 of the nozzle substrate 10.

[0170] On the inner wall 102 of the nozzle 30 , the intermediate layer 51 is the outermost layer.

[0171] The layer formed on the inner wall 102 of the nozzle 30 preferably does not contain a fluorine compound.

[0172] <Flow path substrate>

[0173] The flow path substrate 20 is, for example, a substrate made of silicon, which may be a single crystal silicon substrate or a polycrystalline silicon substrate. Figure 1 As shown, the fluid path substrate 20 is composed of a wall member 21 and a cover member 22. Preferably, the wall member 21 and the cover member 22 are bonded together by adhesive or the like. A liquid flow path 40 is formed in the fluid path substrate 20 and communicates with the nozzle 30. The liquid flow path 40 includes a nozzle communication channel 41, a pressure chamber 42, and a liquid supply channel 43.

[0174] The nozzle communication passage 41 is a flow path connecting the pressure chamber 42 and the nozzle 30. The nozzle communication passage 41 is preferably linear in cross-sectional view.

[0175] The pressure chamber 42 is a flow path whose volume changes when a driving voltage is applied. For example, the pressure chamber 42 has a roughly square planar shape when viewing the liquid ejection head 100 from above. One of the two diagonal corners is provided with a liquid outlet for the nozzle communication channel 41, and the other is provided with a liquid inlet, i.e., a liquid supply channel 43. The planar shape of the pressure chamber 42 is not limited to a roughly square shape; it may also be rectangular, trapezoidal, or the like.

[0176] The liquid supply channel 43 is a flow path connected to a liquid tank (not shown) when the liquid discharge head 100 is assembled into a liquid discharge device described later. Liquid is supplied from the liquid tank to the pressure chamber 42 via the liquid supply channel 43. The arrows in the figure indicate the direction of liquid flow.

[0177] The liquid tank (not shown) and the liquid discharge head 100 are connected by, for example, a hose. The hose preferably does not contain a fluorine compound.

[0178] The liquid discharge head 100 is on the inner wall 201 of the liquid flow path 40. Figure 1 The inner wall 102 of the nozzle 30 shown in FIG. 1 also has an intermediate layer 51. The intermediate layer 51 provided on the inner wall 201 of the liquid flow path 40 is the same as the intermediate layer 51 provided on the discharge surface 101 of the nozzle substrate 10. Specifically, the inner wall 201 of the liquid flow path 40 includes the surface of the wall member 21 on the side where the liquid flow path 40 is formed, the surface of the cover member 22 on the side where the liquid flow path 40 is formed, and the surface of the nozzle substrate 10 on the side where the liquid flow path 40 is formed.

[0179] On the inner wall 201 of the liquid flow path 40 , the intermediate layer 51 is the outermost layer.

[0180] The layer formed on the inner wall 201 of the liquid flow path 40 preferably does not contain a fluorine compound.

[0181] In addition, the structure of the flow path substrate 20 is Figure 1 In addition to the structure shown, it can also be Figure 4 The structure shown. Figure 4 This is an example in which the intermediate layer 51 is composed of two layers: a first intermediate layer 51A and a second intermediate layer 51B.

[0182] Figure 4 This is a schematic cross-sectional view showing a modified example of the liquid ejection head of the present invention.

[0183] like Figure 4 As shown, the liquid ejection head 100A includes a nozzle substrate 10 and a flow path substrate 20A having a liquid flow path 60 formed thereon, which communicates with the nozzles 30. The structure of the nozzle substrate 10 is as described above. The liquid flow path 60 includes a nozzle communication channel 61, a pressure chamber 62, a liquid supply channel 63, and a circulation channel 64.

[0184] The nozzle communication passage 61 , similar to the nozzle communication passage 41 described above, is a flow path connecting the pressure chamber 62 and the nozzle 30 .

[0185] The pressure chamber 62 , like the above-described pressure chamber 42 , is a flow path whose volume changes when a driving voltage is applied.

[0186] The liquid supply channel 63 , like the liquid supply channel 43 , is a flow path connected to a liquid tank (not shown) when the liquid ejection head 100A is assembled into a liquid ejection device described later.

[0187] The circulation flow path 64 is connected to a liquid tank (not shown) when the liquid ejection head 100A is assembled into a liquid ejection device (described later). Liquid is delivered to the nozzle 30 via the liquid supply channel 63, the pressure chamber 62, and the nozzle communication channel 61. However, liquid that is not ejected from the nozzle opening 31 of the nozzle 30 is recovered into the liquid tank via the circulation flow path 64.

[0188] The liquid ejection head 100A has an intermediate layer 51 on the inner wall 201A of the liquid flow path 60, similar to the inner wall 201 of the liquid flow path 40. The intermediate layer 51 provided on the inner wall 201A of the liquid flow path 60 is similar to the intermediate layer 51 provided on the inner wall 201 of the liquid flow path 40.

[0189] <Layer formation method>

[0190] Next, a method for forming the first intermediate layer 51A, the second intermediate layer 51B, and the liquid-repellent layer 52 on the nozzle substrate 10, the nozzle 30, and the fluid path substrate 20 will be described. The first intermediate layer 51A, the second intermediate layer 51B, and the liquid-repellent layer 52 are preferably formed after the nozzle substrate 10 and the fluid path substrate 20 are bonded together to form a bonded body. Furthermore, when only one intermediate layer is provided, it can be formed using the same method as when two layers are provided.

[0191] The method for forming the intermediate layer is not particularly limited, and may be atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0192] Furthermore, the intermediate layer can be formed by sputtering. When sputtering is used, it is preferable to form the intermediate layer on each of the nozzle substrate 10 and the flow path substrate 20 and then bond the nozzle substrate 10 and the flow path substrate 20 together.

[0193] First, before forming the first intermediate layer 51A on the surface of the assembly of the nozzle substrate 10 and the flow path substrate 20, it is preferred to preliminarily perform a surface treatment on the surface of the assembly. Examples of surface treatments include UV ozone treatment and oxygen plasma treatment. Of these, oxygen plasma treatment is preferred from the perspective of improving the adhesion between the assembly and the first layer. The oxygen plasma irradiation conditions can be appropriately adjusted, for example, under conditions of an output power of 100W to 200W, a flow rate of 50mL / min to 200mL / min, and an irradiation time of 1 minute to 10 minutes.

[0194] Next, the first intermediate layer 51A is formed on the surface of the surface-treated bonded body. Specifically, the first intermediate layer 51A is formed on the ejection surface 101 of the nozzle substrate 10 , the inner wall 102 of the nozzle 30 , and the inner wall 201 of the liquid flow path 40 .

[0195] The first intermediate layer 51A is preferably formed by atomic layer deposition (ALD). ALD methods that are generally known can be used. ALD forms a dense layer, which effectively suppresses the permeation of alkaline liquids.

[0196] The first intermediate layer 51A can be formed by repeating the following four steps, for example: placing the surface-treated bonded body in an ALD chamber, introducing a precursor gas after introducing H2O gas; exhausting the remaining gas; introducing H2O gas; and exhausting the remaining gas.

[0197] First, hydroxyl groups are formed on the surface of the bonded body by introducing H2O gas. Next, the hydroxyl groups formed on the surface of the bonded body react with the precursor by introducing a precursor gas. Furthermore, the precursor that reacts with the hydroxyl groups reacts with H2O by introducing H2O gas.

[0198] Examples of the precursor used when forming the tantalum oxide layer as the first intermediate layer 51A include tert-butyliminotris(diethylamino)tantalum (TBTDET), tert-butyliminotris(dimethylamino)tantalum (TBTDMT), tert-butyliminotris(ethylmethylamino)tantalum (TBTEMT), ethyliminotris(diethylamino)tantalum (EITDET), ethyliminotris(dimethylamino)tantalum (EITDMT), ethyliminotris(ethylmethylamino)tantalum (EITEMT), tert-amyliminotris(dimethylamino)tantalum (TAIMAT), tert-amyliminotris(diethylamino)tantalum, penta(dimethylamino)tantalum, and tert-amyliminotris(ethylmethylamino)tantalum.

[0199] Examples of a precursor used when forming a zirconium oxide layer as the first intermediate layer 51A include tetrakis(N-ethylmethylamino)zirconium (TEMAZ) and tris(dimethylamino)cyclopentadienylzirconium (ZAC).

[0200] Examples of a precursor used when forming a titanium oxide layer as the first intermediate layer 51A include tetrakis(dimethylamino)titanium (TDMAT), tetrakis(diethylamino)titanium (TDEAT), and tetrakis(ethylmethylamino)titanium (TEMAT).

[0201] Examples of a precursor used when forming a hafnium oxide layer as the first intermediate layer 51A include tetrakis(dimethylamino)hafnium (TDMAHf), tetrakis(diethylamino)hafnium (TDEAHf), and tetrakis(ethylmethylamino)hafnium (TEMAHf).

[0202] Furthermore, when forming the first intermediate layer 51A, ozone gas may be used instead of H 2 O gas.

[0203] Next, the second intermediate layer 51B is formed on the first intermediate layer 51A.

[0204] The method for forming the second intermediate layer 51B is not particularly limited, and for example, a chemical vapor deposition (CVD) method can be cited. As the CVD method, a generally known method can be used. The method for forming the second intermediate layer 51B is more preferably formed by an atomic layer deposition (ALD) method. As the ALD method, a generally known method can be used. If the ALD method is used, a dense layer is formed, and thus the effect of suppressing the penetration of alkaline liquid is high.

[0205] Next, the liquid-repellent layer 52 is formed on the second intermediate layer 51B.

[0206] The method for forming the liquid-repellent layer 52 is not particularly limited, but the liquid-repellent layer 52 is preferably formed by vapor deposition using a liquid-repellent layer-forming composition containing a compound having a hydrocarbon group with 8 or more carbon atoms after the surface of the second intermediate layer 51B is hydrophilized.

[0207] Examples of the composition for forming the liquid-repellent layer include a silane coupling agent (e.g., a compound represented by formula (2A)). After hydrolysis, the silane coupling agent bonds to the hydrophilic groups formed on the surface of the second intermediate layer 51B. This improves the adhesion between the liquid-repellent layer 52 and the second intermediate layer 51B, thereby suppressing the permeation of alkaline liquids.

[0208] Examples of hydrophilic treatments include UV ozone treatment and oxygen plasma treatment. Oxygen plasma treatment is preferred. Irradiation conditions can be appropriately adjusted, for example, at an output of 100 to 200 W, a flow rate of 50 to 200 mL / min, and an irradiation time of 1 to 10 minutes.

[0209] The film formation method using the vapor deposition method can be performed by placing the bonded body including the first intermediate layer 51A and the second intermediate layer 51B in a vacuum chamber and placing the silane coupling agent in a vapor deposition boat. The vapor deposition temperature is preferably 100°C to 300°C.

[0210] Furthermore, to further improve the adhesion between the second intermediate layer 51B and the liquid-repellent layer 52, the bonded structure comprising the first intermediate layer 51A, the second intermediate layer 51B, and the liquid-repellent layer 52 is preferably maintained in a high-temperature, high-humidity environment after film formation. For example, the bonded structure comprising the first intermediate layer 51A, the second intermediate layer 51B, and the liquid-repellent layer 52 is maintained at a temperature of 50 to 90°C and a relative humidity of 50% to 90% for 6 to 24 hours.

[0211] Next, the liquid-repellent layer 52 provided on the inner wall 102 of the nozzle 30 and the inner wall 201 of the liquid flow path 40 is removed.

[0212] For example, by sticking tape on the surface of the liquid-repellent layer 52 provided on the ejection surface of the nozzle substrate 10 and performing oxygen plasma treatment on the nozzle 30 and the liquid flow path 40, the liquid-repellent layer 52 provided on the inner wall 102 of the nozzle 30 and the inner wall 201 of the liquid flow path 40 can be removed.

[0213] Figure 5 This is a cross-sectional view showing another embodiment of the liquid ejection head of the present invention.

[0214] like Figure 5 As shown, the liquid ejection head 500 further includes a piezoelectric element 70 in addition to the liquid ejection head 100A.

[0215] The structure of the liquid ejection head 100A is as described above. The cover member 22 in the liquid ejection head 100A functions as a vibration plate in the liquid ejection head 500 .

[0216] A piezoelectric element 70 having a laminated structure of a lower electrode 71 , a piezoelectric layer 72 , and an upper electrode 73 is provided on the cover member (vibration plate) 22 . The piezoelectric element 70 is provided above the pressure chamber 62 .

[0217] The upper electrode 73 is an independent electrode patterned to correspond to the shape of the pressure chamber 62. When a driving voltage is applied to the upper electrode 73 of the piezoelectric element 70 located above the pressure chamber 62 based on input data, the piezoelectric element 70 and the cover member (vibrating plate) 22 deform, causing the volume of the pressure chamber 62 to change. This pressure change within the pressure chamber 62 causes liquid to be discharged from the nozzle opening 31 of the nozzle 30 via the nozzle communication channel 61.

[0218] Alternatively, a heater may be provided inside the pressure chamber 62 as a pressure generating element instead of the piezoelectric element, and a driving voltage may be supplied to the heater to generate heat, thereby utilizing film boiling to discharge the liquid inside the pressure chamber 62 from the nozzle opening 31 .

[0219] [Liquid dispensing device]

[0220] The liquid discharge device of the present invention comprises: a liquid discharge head; a transport mechanism for transporting a substrate; and a drying mechanism for drying the liquid discharged onto the substrate. Hereinafter, an inkjet recording device will be described as an example of the liquid discharge device.

[0221] An inkjet recording device, for example, includes: a plurality of inkjet heads (an example of a liquid ejection head), which are arranged according to the color of the ink; an ink storage unit, which stores the ink supplied to each inkjet head; a paper supply unit, which supplies a substrate (recording paper); a curl elimination processing unit, which removes the curl of the recording paper; a conveying unit, which is arranged opposite to the ejection surface of each inkjet head and conveys the recording paper; a drying unit, which dries the liquid (specifically, ink) ejected onto the recording paper; an image detection unit, which reads the image recording result; and a paper discharge unit, which discharges the image recorded material to the outside.

[0222] The configurations of the inkjet recording device other than the inkjet head are the same as conventionally known configurations. For example, International Publication No. 2017 / 073526 and Japanese Patent Application Laid-Open No. 2022-049414 can be referred to.

[0223] The liquid discharge device of the present invention preferably has a liquid circulation mechanism for circulating the liquid between the liquid discharge head and the liquid tank. Figure 4The liquid discharge device of the liquid discharge head 100A shown can circulate liquid between the liquid discharge head and the liquid tank.

[0224] [Method for Manufacturing Liquid Discharge Structure]

[0225] In the method for manufacturing a liquid discharge structure of the present invention, a liquid repellent layer is formed by vapor deposition using a liquid repellent layer forming composition containing a compound having a hydrocarbon group having 8 or more carbon atoms on the discharge surface of a nozzle substrate having a nozzle for discharging liquid.

[0226] The details of the nozzle substrate are as described above.

[0227] The method for forming the liquid-repellent layer by the vapor deposition method is as described above.

[0228] By forming the liquid-repellent layer by a vapor deposition method, a liquid discharge structure having excellent wipe resistance can be manufactured.

[0229] [Laminated body]

[0230] The laminate of the present invention comprises a substrate and a liquid-repellent layer disposed on the substrate, wherein the liquid-repellent layer comprises a compound having a hydrocarbon group having 8 or more carbon atoms.

[0231] Preferred embodiments of the substrate are the same as those of the nozzle substrate described above. An intermediate layer and a liquid-repellent layer may be sequentially stacked on the substrate.

[0232] The laminate of the present invention is useful in a liquid discharge structure having an excellent wiping resistance on the discharge surface. The laminate of the present invention can be applied to a liquid discharge structure by forming a nozzle for discharging liquid.

[0233] Example

[0234] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0235] [Examples 1 to 8, Comparative Example 1]

[0236] <Formation of the first intermediate layer>

[0237] The nozzle substrate on which the nozzles are formed is joined to the flow path substrate on which the liquid flow path is formed, and a substrate having a nozzle and a flow path is prepared. Figure 4 The size of the joint body is 25mm×35mm.

[0238] Step (a1): Surface treatment

[0239] The bonded structure was placed in a vacuum chamber. After the chamber was evacuated, the atmosphere was replaced with oxygen to generate an oxygen plasma. The oxygen plasma irradiation conditions were an output of 30 W, a flow rate of 100 mL / min, and an irradiation time of 30 seconds.

[0240] Step (b1): Formation of hafnium oxide layer

[0241] Next, the junction body after process (a1) is arranged in an ALD (Atomic Layer Deposition) chamber, and H2O gas is introduced to form hydroxyl groups on the surface of the junction body. Next, tetrakis(dimethylamino)hafnium (TDMAHf) gas is introduced to react the hydroxyl groups formed on the surface of the junction body with TDMAHf. Then, the remaining gas is exhausted. Next, H2O gas is introduced to react the TDMAHf bonded to the hydroxyl groups in the previous reaction with H2O. Then, the remaining gas is exhausted. Then, the introduction and exhaust of TDMAHf gas and the introduction and exhaust of H2O gas are repeated as a cycle until a predetermined thickness (30nm) is reached, thereby forming a hafnium oxide layer.

[0242] <Formation of the Second Intermediate Layer>

[0243] Step (c1): Silicon oxide film formation

[0244] The bonded body after process (b1) is arranged in an ALD (Atomic Layer Deposition) chamber, and H2O gas is introduced to form hydroxyl groups on the surface of the bonded body. Next, tris(dimethylamino)silane (TDMAS) gas is introduced to react the hydroxyl groups formed on the surface of the bonded body with TDMAS. Then, the remaining gas is exhausted. Next, H2O gas is introduced to react the TDMAS bonded to the hydroxyl groups in the previous reaction with H2O. Then, the remaining gas is exhausted. Then, the introduction and exhaust of TDMAS gas and the introduction and exhaust of H2O gas are repeated as a cycle until the specified thickness (30nm) is reached, thereby forming a silicon oxide layer.

[0245] <Formation of liquid-repellent layer>

[0246] Step (d1): Hydrophilization treatment

[0247] Next, the bonded body after step (c1) was placed in a vacuum chamber. After the interior of the vacuum chamber was evacuated, oxygen was replaced to generate an oxygen plasma. The oxygen plasma irradiation conditions were set to an output power of 100 W, a flow rate of 100 mL / min, and an irradiation time of 1 minute.

[0248] Step (e1): Vapor deposition of silane coupling agent

[0249] Next, the bonded body after step (d1) was placed in a vapor deposition chamber, and the silane coupling agent listed in Table 1 was added to a tungsten boat.

[0250] After the temperature of the tungsten boat reached 70° C., the shutter was opened, and while monitoring the film thickness using a crystal oscillator, the shutter was closed after the film thickness reached 3 nm to vapor-deposit the silane coupling agent.

[0251] Step (f1): Storage in a high temperature and high humidity environment

[0252] Next, to promote the hydrolysis reaction of the silane coupling agent and the fusing reaction between the bonded product and the silane coupling agent after step (e1), the bonded product was left to stand for 12 hours at a temperature of 60°C and a humidity of 90%. The resulting liquid-repellent layer had a contact angle with water of 60° or greater. The contact angle with water was measured at 25°C using a fully automatic contact angle meter (product name "DM-701", manufactured by Kyowa Interface Science Co., Ltd.).

[0253] Step (g1): Removal of the liquid-repellent layer formed on the inner wall of the nozzle and the inner wall of the liquid flow path

[0254] Next, tape was applied to the nozzle substrate surface of the assembled structure after step (f1), and the nozzle and liquid flow path were treated with oxygen plasma from the surface of the flow path substrate opposite to the surface bonded to the nozzle substrate. This removed the lyophobic layer formed on the inner walls of the nozzle and liquid flow path, resulting in a liquid ejection structure.

[0255] [Example 9]

[0256] <Formation of the middle layer>

[0257] After the step (a1), the step (c1) was performed without performing the step (b1), thereby forming a silicon oxide layer.

[0258] <Formation of liquid-repellent layer>

[0259] Then, the same method as steps (d1) to (g1) of Example 1 was carried out to obtain a liquid discharge structure.

[0260] The details of the silane coupling agents described in Table 1 are as follows: In Example 8, Compound 1 and Compound 2 were used at a ratio of 1:1 (mass ratio).

[0261] (Compound 1)

[0262] [Chemical Formula 1]

[0263]

[0264] (Compound 2)

[0265] [Chemical Formula 2]

[0266]

[0267] (Compound 3)

[0268] [Chemical Formula 3]

[0269]

[0270] (Compound 4)

[0271] [Chemical Formula 4]

[0272]

[0273] (Compound 5)

[0274] [Chemical Formula 5]

[0275]

[0276] (Compound 6)

[0277] [Chemical Formula 6]

[0278]

[0279] (Compound 7)

[0280] [Chemical Formula 7]

[0281]

[0282] (Compound A)

[0283] [Chemical Formula 8]

[0284]

[0285] It was confirmed that the liquid-repellent layers in Examples 1 to 9 contained a compound having a partial structure represented by formula (1).

[0286] The obtained liquid discharge structure was evaluated for liquid repellency, abrasion resistance, and alkali resistance of the discharge surface. The evaluation method was as follows.

[0287] (lyophobicity)

[0288] A black ink described in

[0272] of Japanese Patent Application Laid-Open No. 2015-180710 was prepared. Sodium hydroxide was added to the prepared black ink to adjust the pH to 10, which served as an evaluation ink. The static contact angle of the liquid ejection structure surface was measured using the evaluation ink. The contact angle relative to the ink was measured at 25°C using a fully automatic contact angle meter (product name "DM-701," manufactured by Kyowa Interface Science Co., Ltd.).

[0289] The evaluation criteria are as follows: It can be said that the larger the contact angle, the better the liquid repellency.

[0290] A: The contact angle is 60° or more and less than 90°.

[0291] B: The contact angle is 55° or more and less than 60°.

[0292] C: The contact angle is 50° or more and less than 55°.

[0293] D: The contact angle is less than 50°.

[0294] (Wipe resistance)

[0295] First, the static contact angle of the liquid discharge structure surface was measured using the evaluation ink. The contact angle with respect to the ink was measured at 25°C using a fully automatic contact angle meter (product name "DM-701", manufactured by Kyowa Interface Science Co., Ltd.).

[0296] This contact angle is defined as the "contact angle before wiping."

[0297] Next, the evaluation ink was dripped onto an eraser (product name: "TORCY," manufactured by TORAY INDUSTRIES, Inc.). The nozzle substrate of the prepared liquid ejection structure was pressed against the dripped surface at a constant pressure of 40 kPa, and the structure slid back and forth. After 10,000 reciprocating cycles, the static contact angle of the nozzle substrate surface was measured using the newly prepared evaluation ink.

[0298] This contact angle is designated as the "contact angle after wiping."

[0299] The contact angle before wiping and the contact angle after wiping were used to calculate the contact angle change rate according to the following formula.

[0300] Contact angle change rate (%) = {(contact angle before wiping - contact angle after wiping) / contact angle before wiping} × 100

[0301] The evaluation criteria are as follows: It can be said that the smaller the contact angle change rate, the better the scratch resistance.

[0302] A: The contact angle change rate is less than 20%.

[0303] B: The contact angle change rate is 20% or more and less than 30%.

[0304] C: The contact angle change rate is 30% or more and less than 40%.

[0305] D: The contact angle change rate is 40% or more.

[0306] (Alkali resistance)

[0307] First, the static contact angle of the liquid discharge structure surface was measured using the evaluation ink. The contact angle with respect to the ink was measured at 25°C using a fully automatic contact angle meter (product name "DM-701", manufactured by Kyowa Interface Science Co., Ltd.).

[0308] This contact angle is referred to as "contact angle before immersion."

[0309] Next, the prepared liquid ejection structure was immersed in the evaluation ink and allowed to stand in a thermostatic bath set at 60° C. After 200 hours, the static contact angle of the nozzle substrate surface was measured using the newly prepared evaluation ink.

[0310] This contact angle is referred to as "contact angle after immersion."

[0311] The contact angle change rate was calculated using the contact angle before immersion and the contact angle after immersion according to the following formula.

[0312] Contact angle change rate (%) = {(contact angle before immersion - contact angle after immersion) / contact angle before immersion} × 100

[0313] The evaluation criteria are as follows: It can be said that the smaller the contact angle change rate, the better the alkali resistance.

[0314] A: The contact angle change rate is less than 20%.

[0315] B: The contact angle change rate is 20% or more and less than 30%.

[0316] C: The contact angle change rate is 30% or more and less than 40%.

[0317] D: The contact angle change rate is 40% or more.

[0318] The evaluation results are shown in Table 1. Table 1 lists the number of carbon atoms and type of the hydrocarbon group of the compound contained in the liquid-repellent layer. Furthermore, if the compound contained in the liquid-repellent layer includes a linking group in addition to the hydrocarbon group, it is indicated as "Y", and if it does not include a linking group, it is indicated as "N".

[0319] [Table 1]

[0320]

[0321] As shown in Table 1, it was found that in Examples 1 to 9, the liquid-repellent layer contained a compound having a hydrocarbon group having 8 or more carbon atoms, and therefore the discharge surface had excellent abrasion resistance.

[0322] On the other hand, in Comparative Example 1, the liquid-repellent layer does not contain a compound having a hydrocarbon group having 8 or more carbon atoms, and the wiping resistance of the discharge surface is poor.

[0323] Explanation of symbols

[0324] 10-nozzle substrate, 20, 20A-flow path substrate, 30-nozzle, 31-nozzle opening, 21, 21A-wall component, 22-cover component (vibration plate), 40, 60-liquid flow path, 41, 61-nozzle connecting channel, 42, 62-pressure chamber, 43, 63-liquid supply channel, 51-intermediate layer, 51A-first intermediate layer, 51B-second intermediate layer, 52-lyophobic layer, 64-circulating flow path, 70-piezoelectric element, 71-lower electrode, 72-piezoelectric layer, 73-upper electrode, 100, 100A-liquid ejection head, 101-ejection surface, 102, 201, 201A-inner wall, 500-liquid ejection head.

Claims

1. A liquid discharge structure comprising a nozzle substrate on which a nozzle for discharging liquid is formed, The nozzle substrate has a liquid-repellent layer on the ejection surface. The liquid-repellent layer includes a compound having a hydrocarbon group having 8 or more carbon atoms.

2. The liquid discharge structure according to claim 1, wherein The compound having a hydrocarbon group having 8 or more carbon atoms has a partial structure represented by the following formula (1): LYM-*…(1) In formula (1), L is a hydrocarbon group having 8 or more carbon atoms, Y is a single bond or a divalent linking group, M is a semimetal or metal, *Indicates bonding position to other structures.

3. The liquid discharge structure according to claim 1, wherein The hydrocarbon group having 8 or more carbon atoms is a straight-chain alkyl group having 8 or more carbon atoms.

4. The liquid discharge structure according to claim 2, wherein: In the formula (1), Y is a single bond.

5. The liquid discharge structure according to claim 1, wherein An intermediate layer and a liquid-repellent layer are sequentially provided on the ejection surface of the nozzle substrate.

6. The liquid discharge structure according to claim 5, wherein: The intermediate layer is a layer including at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, hafnium oxide, SiO 2 , SiC, SiN, SiCN, and SiON.

7. The liquid discharge structure according to claim 5, wherein: The middle layer consists of two layers. The discharge surface has a first intermediate layer, a second intermediate layer, and the liquid-repellent layer in this order.

8. The liquid discharge structure according to claim 7, wherein: The first intermediate layer is a layer containing at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide. The second intermediate layer is a layer including at least one selected from the group consisting of SiO 2 , SiC, SiN, SiCN, and SiON. 9 . A liquid ejection head comprising: the liquid ejection structure according to claim 1 ; and a flow path substrate on which a liquid flow path communicating with the nozzle is formed.

10. The liquid discharge head according to claim 9, wherein The liquid ejection head further includes a piezoelectric element. 11 . A liquid discharge device comprising: the liquid discharge head according to claim 9 , a conveying mechanism for conveying a substrate, and a drying mechanism for drying the liquid discharged onto the substrate.

12. A method for manufacturing a liquid discharge structure, wherein: A liquid-repellent layer is formed on a discharge surface of a nozzle substrate on which a nozzle for discharging liquid is formed by a vapor deposition method using a liquid-repellent layer-forming composition containing a compound having a hydrocarbon group having 8 or more carbon atoms.

13. A laminate comprising: substrate; and a liquid-repellent layer disposed on the substrate, The liquid-repellent layer includes a compound having a hydrocarbon group having 8 or more carbon atoms.

Images