Ink-repellent material, method for manufacturing an ink-repellent material, inkjet head, method for manufacturing an article

Abstract

We provide high-performance ink-repellent components and inkjet heads. [Solution] An ink-repellent member having a base containing a metal oxide, wherein a fluorine compound is bonded to the surface of the base, the covalent bonding index between the metal element and oxygen of the metal oxide is 0.44 or less, and the ratio of the atomic weight of the metal element to the sum of the amount of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and the atomic weight of the metal element when the surface of the base is measured by X-ray photoelectron spectroscopy after the following immersion treatments (1) and (2) have been performed on the ink-repellent member is 1 atm% or less. (Immersion treatment) (1) Cut out a test piece from the ink-repellent material including the surface of the base material, place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, and immerse the entire test piece in it. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours.

Description

Technical Field

[0001] The present invention relates to a ink repellent member, a method for manufacturing the ink repellent member, an inkjet head, and a method for manufacturing an article.

Background Art

[0002] As a device for ejecting ink (hereinafter referred to as an inkjet head), there are known a bubble jet that causes droplets to fly by instantaneously vaporizing ink using a heater, a piezo jet that biases droplets using a piezoelectric element, and the like. In order to perform high-quality image recording using an inkjet head, it is necessary that ink droplets be ejected from a discharge port for ejecting ink while maintaining straightness along a predetermined direction. However, if residues of droplets adhere to the surface of the orifice plate around the discharge port, when the ink droplets are ejected, the ink droplets are dragged by the residues and yaw in the ejection direction occurs, and the ink droplets may fly out of the predetermined direction. Therefore, in order to suppress the adhesion of droplet residues around the discharge port, an ink repellent film is provided around the discharge port to form an ink repellent member.

[0003] For example, Patent Document 1 discloses that a base made of an inorganic oxide is provided on the surface of the orifice plate, and a fluorine-containing silane coupling agent (hereinafter also referred to as a fluorine compound) is chemically bonded thereto to form an ink repellent member.

[0004] In addition, in an inkjet head, in order to remove droplet residues, paper powder, etc., it is generally performed to clean the surface of the orifice plate using a wiper or the like. Therefore, the ink repellent member is required to have ink resistance and sliding resistance.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] There was a need for ink-repellent materials with superior performance, even when the substrate contained oxides of metals with low reactivity. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is an ink-repellent member having a substrate containing a metal oxide, wherein a fluorine compound is bonded to the surface of the substrate, the covalent bonding index between the metal element and oxygen of the metal oxide is 0.44 or less, and the ratio of the atomic weight of the metal element to the sum of the atomic weights of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and the metal element, when the surface of the substrate is measured by X-ray photoelectron spectroscopy after the following immersion treatments (1) and (2) have been performed on the ink-repellent member, is 1 atm% or less. (Immersion treatment) (1) Cut out a test piece from the ink-repellent material including the surface of the base material, place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, and immerse the entire test piece in it. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours.

[0008] Furthermore, according to one aspect of the present invention, there is a method for manufacturing an ink-repellent member having a base containing a metal oxide, wherein a fluorine compound is bonded to the surface of the base, characterized in that the covalent bond index between the metal element and oxygen of the metal oxide is 0.44 or less, and the method includes the following steps (1), (2), (3) and (4). (1) A process of plasma treatment of the surface of the substrate in an atmosphere with an oxygen concentration of 50 volume% or more. (2) A step of applying a fluorine compound having a reactive silyl group represented by the following formula (1) onto the surface of the substrate that has been plasma-treated in step (1) and dehydrating and condensing it. *-Si(Y 1 ) n (OR) m (1) (In equation (1), n ​​and m are integers between 0 and 3, and n + m = 3. Y 1 Each of the following independently represents an alkyl group, a chloro group, or a bromo group. Each of the following independently represents a hydrogen atom or an alkyl group. * indicates the bond position in the fluorine compound. (3) A step in which the fluorine compound applied to the substrate in step (2) is allowed to bond to the surface of the substrate by being present in an environment of 25±2°C and 50±10%RH for 48 hours or more. (4) After step (3), a step of heating the surface of the fluorine compound and the substrate.

[0009] Furthermore, according to one aspect of the present invention, an inkjet head is provided, having the above-mentioned ink-repellent member, wherein a discharge port for discharging liquid is arranged on the side of the ink-repellent member where the base material is provided. Furthermore, according to another aspect of the present invention, a method for manufacturing an article is provided, comprising the step of discharging liquid using the above-mentioned inkjet head, wherein the liquid is an ink containing a functional material for forming a functional thin film or a functional element. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an ink-repellent material with excellent performance and an inkjet head. [Brief explanation of the drawing]

[0011] [Figure 1] (a) a top view and (b) a bottom view of an inkjet head 100 according to one embodiment of the present invention, and (c) a partial perspective view showing a part of the cross section cut along the line A-A' shown in (a) and (b). [Figure 2] (a) A schematic diagram showing the state of an ink-repellent member according to one embodiment of the present invention, and (b) A diagram showing the relationship between flat and convex portions in the uneven surface structure of an ink-repellent member according to one embodiment of the present invention. [Figure 3]This figure shows the relationship between the treatment time and the percentage of tantalum atomic weight [atm%] when an immersion treatment is performed on an ink-repellent member according to one embodiment of the present invention and an ink-repellent member according to the prior art. [Modes for carrying out the invention]

[0012] With reference to the drawings, embodiments of the present invention, such as an ink-repellent member and an inkjet head, will be described. In the following, terms such as "ink-repellent," "ink-repellent member," "ink-repellent agent," and "ink-repellent film" will be used, but these may be replaced with "water-repellent," "water-repellent member," "water-repellent agent," and "water-repellent film" when referring to water-based inks. Furthermore, since the type and use of liquid are not necessarily limited when implementing the present invention, "ink-repellent," "ink-repellent member," "ink-repellent agent," and "ink-repellent film" may be replaced with "liquid-repellent," "liquid-repellent member," "liquid-repellent agent," and "liquid-repellent film" in the following description. The embodiments shown below are illustrative, and for example, those skilled in the art can modify the detailed configuration as appropriate without departing from the spirit of the present invention.

[0013] In the drawings referenced in the following descriptions of embodiments and examples, elements with the same reference numeral are assumed to have the same function unless otherwise specified. Furthermore, the notations "XX or greater and YY or less" or "XX~YY" indicating a numerical range mean a numerical range including the endpoints XX (lower limit) and YY (upper limit), unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0014] In this specification, the liquid being handled may be referred to as "ink," but ink is not limited to liquids used to form letters or images. For example, it may also be a liquid containing functional materials used to form functional thin films such as electrodes or optical filters, or functional elements such as organic EL elements.

[0015] The present invention provides an ink-repellent material having a substrate containing a metal oxide, wherein a fluorine compound is bonded to the surface of the substrate, the covalent bonding index between the metal element and oxygen of the metal oxide is 0.44 or less, and the ratio of the atomic weight of the metal element to the total atomic weight of the carbon atom, oxygen atom, fluorine atom, silicon atom, and metal element, when the surface of the substrate is measured by X-ray photoelectron spectroscopy after the following immersion treatments (1) and (2) have been performed on the ink-repellent material, is 1 atm% or less. (Immersion treatment) (1) Cut out a test piece from the ink-repellent material, including the surface of the substrate (the surface of the ink-repellent material), and place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, so that the entire test piece is submerged. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours. In this specification, the term "ink-repellent member" refers to a member that includes a substrate having a surface to which a fluorine compound is bonded (a member that includes a substrate to which a fluorine compound is bonded).

[0016] The inventors of the present invention have conducted extensive research to obtain an ink-repellent material that can maintain long-term ink resistance and sliding resistance even when using an oxide of a metal (e.g., a transition metal) with a covalent bonding index with oxygen of 0.44 or less as a substrate. As a result, they found that the above objective can be achieved by plasma-treating the metal oxide in an oxygen atmosphere, applying a fluorine compound, leaving it in an environment of 25±2°C and 50±10%RH humidity for 48 hours or more, and then heating it to bond the materials. Note that the ink resistance of an ink-repellent material refers to, for example, the small change in the contact angle, which is one of the performance indices of an ink-repellent material, even when ink is in contact with the ink-repellent material for a long time. When bonding a fluorine-containing silane coupling agent to a substrate, silicon oxide is generally used as the substrate, but as in Patent Document 1, a transition metal element with high liquid resistance may be added to the substrate. However, it has been known that when the covalent bonding between the metal element (hereinafter also referred to as M) added to the metal oxide substrate and oxygen is low, the reactivity is low, and it is difficult to form an MO bond between the silane coupling agent and M added to the substrate. Furthermore, while transition metal oxides exhibit excellent liquid resistance, some elemental species have low covalent bonding ability with oxygen, making it difficult to form bonds with silane coupling agents containing fluorine compounds, which are commonly used as ink-repellent agents. Therefore, the inventors have found that, for example, ink-repellent members using transition metal oxides as a substrate suffer from a decrease in ink-repellent performance due to prolonged ink contact and sliding.

[0017] However, after diligent research by the inventors, it was found that many bonds are formed when a fluorine compound is applied and left in an environment of 25±2°C and 50±10%RH humidity for 48 hours or more, followed by heating. Furthermore, it was found that an uneven structure containing the fluorine compound is also formed on the surface of the ink-repellent material. This uneven structure is continuously formed on a film in which one or more layers of fluorine compound ink-repellent films are stacked. By allowing the reaction to proceed slowly in an environment close to room temperature, not only are bonds formed between the silane coupling functional groups of the ink-repellent film and the substrate, but bonds are also formed between the fluorine compounds themselves, resulting in the formation of a stronger bond network. Due to the formation of this strong network, an uneven structure appears locally on the layered ink-repellent film. It is believed that by leaving the material under the above conditions, a high-density ink-repellent film is formed, making it possible to realize an ink-repellent material with excellent ink resistance and sliding resistance.

[0018] (Inkjet head) First, an inkjet head according to one embodiment of the present invention may be an inkjet head having an ink-repellent member according to the present invention, and having a discharge port for discharging liquid on the side where the base of the ink-repellent member is provided. The configuration of the inkjet head according to this embodiment will now be described. Figure 1(a) is a top view of the inkjet head 100 according to this embodiment, and Figure 1(b) is a bottom view of the inkjet head 100. Figure 1(c) is a partial perspective view showing a part of the cross-section cut along the line A-A' shown in Figures 1(a) and 1(b).

[0019] The inkjet head 100 comprises a first channel substrate 1 as a first component, a second channel substrate 2 as a second component, an adhesive layer 3, an ejection port 4, an ejection energy generating element 5, an orifice plate 6 (ink-repellent component), an electrode 7, and an ink tank chamber. Note that the ink tank chamber is not shown in Figures 1(a) to 1(c). In addition, components of the inkjet head that are not directly related to the description of the present invention (e.g., electrical circuits and wiring) are not shown.

[0020] The first channel substrate 1 and the second channel substrate 2, the first channel substrate 1 and the orifice plate 6, and the second channel substrate 2 and the ink tank chamber are joined together via an adhesive layer 3 to form a channel structure. The channel structure has a first through-channel 8, a second through-channel 9, and a third through-channel 19, which are interconnected to form an ink supply path. Note that in Figure 1(c), only a portion of the adhesive layer 3 is shown for illustrative purposes.

[0021] Ink is supplied from the ink tank chamber through the second through-channel 9 formed in the second flow channel substrate 2 and the first flow channel substrate 1, respectively, to the liquid flow channel 10, where it is given discharge energy by the discharge energy generating element 5 and discharged from the discharge port 4. Ink that is not discharged from the discharge port 4 is returned to the ink tank chamber through the first through-channel 8 formed in the first flow channel substrate 1 and the third through-channel 19 (recirculation return path) formed in the second flow channel substrate 2.

[0022] Multiple discharge ports 4 are arranged on the orifice plate 6, but the arrangement (number and position) of the discharge ports 4 is not limited to the illustrated example. On the outer surface of the orifice plate 6, i.e., the orifice surface 6a, which is the surface opposite to the liquid flow path 10, a fluorine compound is bonded to the surface of the substrate described later, forming an ink-repellent film. However, no ink-repellent film is formed on the discharge ports 4 arranged on the orifice surface 6a. The first flow path substrate 1 is provided with discharge energy generating elements 5 for discharging liquid at positions corresponding to each discharge port 4, and the discharge energy generating elements 5 are driven in response to electrical signals transmitted from the outside via electrodes 7. As the discharge energy generating elements 5, for example, an electrothermal conversion element or a piezoelectric element is preferably used. Silicon is preferred as the base material for the orifice plate 6, but other materials such as silicon carbide, silicon nitride, various types of glass such as quartz glass and borosilicate glass, various ceramics such as alumina and gallium arsenide, and resins such as polyimide may also be used. In this embodiment, the orifice plate is used as the ink-repellent component, but the inkjet head itself may also be used as the ink-repellent component.

[0023] (Primer) The substrate provided on the outer surface (orifice surface 6a) of the orifice plate 6 shown in Figure 1 is composed of inorganic oxides. The substrate can form hydroxyl groups on its surface and chemically bond with fluorine compounds (fluorine-containing silane coupling agents) that have reactive silyl groups. By chemically bonding with the substrate, the fluorine compounds can improve adhesion to the substrate. The substrate can be formed on the base material as a base film or base layer, but if the base material itself (bulk material) is composed of inorganic oxides, the base material itself may be used as the substrate.

[0024] In this invention, the substrate contains an oxide of a metal (e.g., a transition metal) with a covalent bonding index with oxygen of 0.44 or less as an inorganic oxide. Such metal oxides have excellent liquid resistance. The covalent bonding ability with oxygen of the metal elements contained in the metal oxide can be calculated from their respective electronegativity. A larger value indicates higher covalent bonding and easier formation of bonds with oxygen. Conversely, a smaller value indicates difficulty in forming bonds with oxygen. This can be similarly considered as the ease of bond formation with commonly used silane coupling agents. The covalent bonding index E, which indicates covalent bonding with oxygen, can be derived from the following formula (A).

number

[0025] Examples of metal elements in the metal oxides of this invention include transition metals (transition elements) from groups 3 to 11 of the periodic table, such as tantalum, zirconium, and hafnium. In particular, tantalum is preferred from the viewpoint of the proportion of oxygen atoms on the surface when it is formed as a metal oxide. Examples of substrates in this invention include tantalum pentoxide, zirconium dioxide, and hafnium dioxide. In particular, tantalum pentoxide is preferred from the viewpoint of the proportion of oxygen atoms on the surface.

[0026] As a substrate containing metal oxides, a base film can be formed on a substrate (e.g., silicon) by sputtering, ion-assisted vapor deposition, atomic layer deposition (ALD), etc. Of these, the ALD method is preferred from the viewpoint of forming a high-density film. Higher density further improves ink resistance to alkaline inks.

[0027] When a base film is provided as a substrate on a base material, silicon is generally used as the substrate for the layer beneath the base film. In this case, from the viewpoint of protecting the silicon from the ink, the thickness of the base film is preferably 10 nm or more, and more preferably 50 nm or more. Furthermore, from the viewpoint of suppressing cohesive failure during sliding, it is preferably 300 nm or less, and more preferably 200 nm or less.

[0028] (Surface treatment of the base material) A method for manufacturing an ink-repellent member according to one embodiment of the present invention is a method for manufacturing an ink-repellent member having a base containing a metal oxide, wherein a fluorine compound is bonded to the surface of the base, characterized in that the covalent bond index between the metal element of the metal oxide and oxygen is 0.44 or less, and the method includes the following steps (1), (2), (3) and (4). (1) A process of plasma treatment of the surface of a substrate without bonded fluorine compounds in an atmosphere with an oxygen concentration of 50 volume% or more. (2) A step of applying a fluorine compound having a reactive silyl group represented by the following formula (1) onto the surface of the substrate that has been plasma-treated in step (1), and then dehydrating and condensing it. *-Si(Y 1 ) n(OR) m (1) (In formula (1), n and m are integers from 0 to 3, and n + m = 3. Y 1 each independently represents an alkyl group, a chloro group, or a bromo group. R each independently represents a hydrogen atom or an alkyl group. * indicates the bonding position in the fluorine compound.) (3) A step of allowing the fluorine compound applied in step (2) to exist for 48 hours or more in an environment of a temperature of 25 ± 2°C and a humidity of 50 ± 10% RH and bonding it to the surface of the substrate (4) A step of heating the surface of the fluorine compound and the substrate after step (3)

[0029] The surface treatment of the substrate is performed for the purpose of forming hydroxy groups, which are bonding points with the silane coupling agent, on the substrate surface. When surface treatment is performed on the substrate surface containing a metal oxide, the surface becomes a highly active state and reacts with moisture in the air to form hydroxy groups. By subjecting these hydroxy groups and the fluorine compound to a silane coupling reaction, an M - O - Si bond can be formed on the surface.

[0030] Examples of the surface treatment method include plasma treatment in which plasma is irradiated in a vacuum and sputtering treatment using argon. In the present invention, plasma treatment in an oxygen atmosphere is preferred. This is because even if the energy applied to the surface is large enough to eject oxygen, if the surrounding is an oxygen atmosphere, it is considered that the oxygen can fill the depletion, and hydroxy groups can be formed at a high density.

[0031] In the present invention, the oxygen concentration in the atmosphere of step (1) for performing plasma treatment is preferably 50% by volume or more, more preferably 75% by volume or more, and still more preferably 80% by volume or more. Treatment may be performed in an atmosphere containing only oxygen (oxygen concentration is 100% by volume). Also, a bias may be applied to accelerate the plasma generated during the treatment for treatment. By doing so, the surface treatment is promoted, and further hydroxy groups can be formed.

[0032] When a transition metal oxide is used as the base material, plasma treatment in an oxygen atmosphere can increase the amount of hydroxyl groups, which are reactive groups, and form many bonds with fluorine compounds, thus enabling the creation of an ink-repellent material with excellent sliding resistance and ink resistance.

[0033] (Fluorine compounds) The fluorine compound used in the ink-repellent material according to the present invention has a linear main chain structure, and one of the ends of the main chain can form a chemical bond (MO-Si) with a hydroxyl group on the surface of the underlying metal oxide. In order to form the MO-Si bond, the fluorine compound used in the manufacture of the ink-repellent material has at least one reactive silyl group represented by the following formula (1). *-Si(Y 1 ) n (OR) m (1) In equation (1), n ​​and m are integers between 0 and 3, and n + m = 3. For example, m can represent 3 and n can represent 0. 1 Each of these independently represents an alkyl group, a chloro group, or a bromo group. Each of these independently represents a hydrogen atom or an alkyl group. 1 It is preferable that Y represents a methyl group. 1 A smaller number of carbon atoms makes it easier to suppress the decrease in reactivity due to steric hindrance. It is preferable that R represents a methyl group, as this leads to faster hydrolysis of the fluorine compound and a faster reaction.

[0034] Furthermore, it is preferable that the other end of the fluorine compound has a perfluoromethyl structure (perfluoromethyl group). The perfluoromethyl structure has a low surface free energy and can exhibit high ink repellency.

[0035] From the viewpoint of ensuring ink repellency and sliding resistance, the main chain structure of the fluorine compound preferably has a perfluoropolyether (hereinafter also referred to as PFPE) structure. In other words, the preferred structure of the fluorine compound used in the manufacture of the ink-repellent material can be represented by the following formula (10). [ka] In formula (10), R 1 R represents a reactive silyl group represented by formula (1), 2 This exhibits a structure having a perfluoropolyether structure.

[0036] The fluorine compound preferably has at least one of the following repeating structures as a PFPE structure: the repeating structure represented by formula (2), the repeating structure represented by formula (3), the repeating structure represented by formula (4), and the repeating structure represented by formula (5). [ka] [ka] [ka] [ka] In equations (2), (3), (4), and (5), n1, n2, n3, and n4 each independently represent an integer greater than or equal to 1.

[0037] Preferred specific examples of fluorine compounds include the compound represented by formula (6), the compound represented by formula (7), the compound represented by formula (8), and the compound represented by formula (9). [ka] (In equation (6), s1, t1, and u1 each independently represent an integer greater than or equal to 1.) [ka] (In equation (7), s² and t² each independently represent an integer greater than or equal to 1.) [ka] (In equation (8), s3 represents an integer greater than or equal to 1.) [ka] (In equation (9), s4, t4, and u4 each independently represent an integer greater than or equal to 1.)

[0038] The fluorine compound included in the ink-repellent material is preferably a fluorine compound having a main chain with a perfluoropolyether structure and a perfluoromethyl group at its terminal. That is, the preferred structure of the fluorine compound when it is bonded to the surface of a metal oxide substrate via MO-Si bonds can be represented by the following formula (11). [ka] (In formula (11), R 2 It exhibits a structure having a perfluoropolyether structure, R 3 The symbol (*) indicates a Si-O bond, and the fluorine compound is chemically bonded to the substrate surface via MO-Si bonds, which include this Si-O bond.

[0039] The number-average molecular weight of the fluorine compound is preferably 4,000 or more. 19 It can be calculated by measuring the 1F-NMR spectrum and determining the integral ratio with the terminal CF3 group.

[0040] (Manufacturing method for ink-repellent material) Next, we will explain a method for bonding fluorine compounds to the surface of a substrate containing metal oxides. Fluorine compounds can be bonded by silane coupling treatment. An example is given below.

[0041] First, a substrate containing a metal oxide is formed on a substrate, such as an orifice plate. One method for forming the metal oxide substrate is by atomic layer deposition (ALD).

[0042] Next, hydroxyl groups are formed on the surface of the substrate by the plasma treatment described above. Then, a fluorine compound is applied to the surface of the substrate on which the hydroxyl groups have been formed. There are no particular restrictions on the application method, and examples include vacuum deposition, thermal deposition, spray coating, spin coating, and dip coating.

[0043] Next, the alkoxysilyl or silyl halide groups at the ends of the fluorine compounds are hydrolyzed and converted into silanol groups (Si-OH groups). Then, a dehydration condensation reaction occurs between the silanol groups of the fluorine compounds and the hydroxyl groups formed on the surface of the substrate, forming MO-Si bonds. Depending on the orientation of the fluorine compounds, Si-O-Si bonds may also be formed between the fluorine compounds themselves.

[0044] Hydrolysis occurs when the silane coupling functional group at the end of a fluorine compound is exposed to moisture, and can also occur due to adsorbed water present on the substrate surface. Dehydration condensation reactions occur at room temperature and can be accelerated by raising the temperature. When bonding a metal oxide substrate to a fluorine compound, at room temperature (e.g., 25°C ± 2°C), the reaction energy required for bonding is insufficient, and bonding between fluorine compounds (Si-O-Si) may occur more easily. Conventionally, to promote bonding between the fluorine compound and the metal oxide substrate (MO-Si), the coated fluorine compound was heated to a high temperature to induce a reaction and increase the density of the repellent ink film.

[0045] However, when the reaction was accelerated by heating at high temperatures, the density of the ink-repellent film did not change regardless of whether the heating time was long or short. This is because when the bonding reaction is rapidly accelerated under high-temperature conditions, the silane coupling functional groups around the substrate bond to the substrate, while those that do not bond bond to each other. As a result, the number of bonds around the substrate film does not change, so heating at high temperatures does not lead to increased density.

[0046] In this invention, the reaction is carried out under mild conditions for a long period of time to deliberately promote bonding between fluorine compounds. In this way, the silane coupling functional groups of the fluorine compounds repeatedly undergo hydrolysis and dehydration condensation, moving to the optimal configuration for each molecule. This makes it possible to form a denser and wider bonding network. Specifically, it is preferable to leave the fluorine compound applied to the substrate in an environment of 25±2℃ and 50±10%RH for 48 hours or more, more preferably for 96 hours or more, and even more preferably for 168 hours or more.

[0047] Subsequently, the applied fluorine compound is heated to over 100°C to promote bonding between the fluorine compound and the substrate. This process allows the fluorine compound, which has a dense bonding network, to bond with the substrate, forming a high-density ink-repellent film.

[0048] Furthermore, with conventional manufacturing methods, aggregates of fluorine compounds formed by the bonding of fluorine compounds themselves do not contribute to bonding with the substrate and are therefore removed during the cleaning process. However, by leaving the material for a long period under mild conditions, as in this case, the aggregates are incorporated as part of the network and remain on the surface of the ink-repellent film even after cleaning. Since these aggregates are also made of fluorine compounds, they contribute to both the ink resistance and sliding resistance of the ink-repellent material.

[0049] The ink-repellent member according to the present invention preferably has an uneven structure containing a fluorine compound. As shown in Figure 2(a), the aforementioned aggregates appear as an uneven structure on the surface of the ink-repellent member. If the ink-repellent film formed on the surface has both flat and convex portions, an improvement in the contact angle due to the lotus leaf effect can be expected. Furthermore, since wear occurs from the convex portions during sliding, the overall lifespan is longer than that of a member without flat and convex portions. In this case, it is preferable to have convex portions where the distance between the apex of the convex portion and the flat portion is 20 nm or more, and it is more preferable to have convex portions where the distance is 30 nm or more. The thickness of the flat portion of the fluorine compound-based ink film is preferably 1 nm or more, and more preferably 5 nm or more.

[0050] After bonding the fluorine compound to the substrate surface, the substrate is cleaned to remove any remaining unbonded fluorine compound. There are no particular restrictions on the cleaning method, but for example, the ink-repellent material can be immersed in a fluorine solvent that is compatible with the fluorine compound. The substrate should be cleaned to the extent that it can be visually confirmed that no fluorine compound remains on it. After drying, the fluorine solvent can be used to evaluate the amount of fluorine compound bonded, ink resistance, and sliding resistance.

[0051] (Percentage of metallic elements contained in the substrate) In one embodiment of the present invention, the ink-repellent member has a proportion of atomic weights of metal elements whose covalent bonding index with oxygen in the substrate is 0.44 or less, and which is 1 atm% (atomic percentage) or less. The proportion of atomic weights of the above metal elements can be measured as follows: The following immersion treatments (1) and (2) are performed on the ink-repellent member to which the fluorine compound is bonded. After that, the surface of the ink-repellent member (surface of the substrate) is measured by X-ray photoelectron spectroscopy (XPS), and the proportion of the atomic weight of the above metal elements to the sum of the amount of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and the atomic weights of the above metal elements is calculated. The smaller the detection rate of the above metal elements in the substrate of the ink-repellent film, the denser the ink-repellent film is formed. (Immersion treatment) (1) Cut a test piece from the ink-repellent material, including the surface of the base material, and place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, so that the entire test piece is submerged. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours.

[0052] The XPS measurement conditions can be as follows when the substrate contains, for example, tantalum oxide. The same applies when measuring other metallic elements. Measuring device: QuanteraII (product name), manufactured by ULVAC-FI, Inc. X-ray source: AlKα Analysis area: φ200μm Pass energy: 140 eV Total number of times: 10 Detection angle: 45° Detected elements: C, O, F, Si, Ta XPS peaks: C1s, O1s, F1s, Si2p, Ta4f

[0053] Hydrofluoroethers are compounds consisting of carbon atoms, fluorine atoms, hydrogen atoms, and ether bonds (-O-). They only dissolve fluorine compounds and are not corrosive. Therefore, the above treatment can remove fluorine compounds that could not be completely removed in the cleaning process, even though they do not chemically bond to the substrate. In other words, the above immersion treatment allows for the evaluation of the ink-repellent film actually formed on the substrate film.

[0054] There are no particular restrictions on the hydrofluoroether-containing fluorinated solvent used in the immersion treatment. Examples of commercially available products include Novec® 7200 (boiling point 76°C, manufactured by 3M, structure C4F9OC2H5), Sumitec Solvent 72 (boiling point 76°C, manufactured by Sumiko Lubricants Co., Ltd.), and SOLBLE RN2000 (boiling point 76°C, Solvex Corporation) (all of which contain compounds with the same structure as Novec 7200 as their main component). The hydrofluoroether-containing fluorinated solvent may also be hydrofluoroether itself (100% hydrofluoroether).

[0055] Unbound fluorinated compounds can also contribute to increased durability, so in practice, it is common to use materials without actively removing them. However, unbound fluorinated compounds diffuse into the ink during contact with the ink and are removed over time. As a result, a substrate with low liquid repellency is exposed, leading to a deterioration of the ink-repellent function. Even if the proportion of transition metal atoms was the same before the above treatment, the amount actually bonded to the substrate changes due to the film formation process. Therefore, by realizing an ink-repellent material with a small amount of transition metal atoms after the above treatment, it is possible to obtain an ink-repellent material with excellent ink resistance.

[0056] As an example, Figure 3 shows the change in the ratio of atomic weights of the metal element (tantalum) when the ink-repellent material according to one embodiment of the present invention used in Example 1 and the conventional ink-repellent material according to the prior art used in Comparative Example 3 are subjected to the above immersion treatment. The ratio of tantalum atomic weights is the ratio of the amount of tantalum atomic weights to the sum of the amounts of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and tantalum atoms.

[0057] The proportion of tantalum atoms immediately after the cleaning process (corresponding to 0 hours of immersion treatment in Figure 3) is the same, but it can be seen that the proportion of tantalum atoms in the conventional ink-repellent material has increased due to the immersion treatment. This indicates that fluorine compounds that could not be completely removed in the cleaning process and remained on the surface of the ink-repellent material were removed by the immersion treatment, resulting in exposed areas of the underlying tantalum oxide. On the other hand, it can be seen that the proportion of tantalum atoms in the ink-repellent material according to the present invention is maintained after 4 hours of treatment. This indicates that, due to the effect of the present invention, aggregates formed by the bonding of fluorine compounds that would normally be removed are retained as part of the ink-repellent film and are therefore not removed by the immersion treatment, preventing exposure of the underlying tantalum oxide. Since the values ​​stabilize after 3 hours or more of treatment in both cases, it can be considered that the removal of aggregates is complete. Therefore, in the present invention, the ink-repellent material is evaluated after 4 hours of immersion treatment.

[0058] From the viewpoint of ink resistance, the percentage of atomic weight of the metal element after the above immersion treatment is preferably 1.0 atm% or less, and more preferably 0.80 atm% or less.

[0059] (Method of manufacturing articles using ink-repellent materials) A method for manufacturing an article according to one embodiment of the present invention is a method for manufacturing an article that includes a step of ejecting a liquid using the above-described ink-repellent member (e.g., an inkjet head), wherein the liquid is an ink containing a functional material for forming a functional thin film or a functional element. The article may be an intermediate product or a final product. The method for manufacturing an article according to this embodiment is suitable for manufacturing articles such as organic EL (OLED) panels using an inkjet head. The method for manufacturing an article according to this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article. [Examples]

[0060] The following are specific examples and comparative examples. (Example 1) A 100nm layer of tantalum pentoxide was deposited on a Φ3-inch silicon substrate using an ALD (Advanced Laser Deposition) deposition system. Next, a silicon substrate with this tantalum pentoxide undercoat was placed in the chamber of the plasma processing apparatus, and the surface of the undercoat was treated. Specifically, after evacuating the chamber, only oxygen was introduced. Then, plasma was generated, and a bias was applied to accelerate the plasma (output power value 120W). This state was maintained for 300 seconds.

[0061] Next, the silicon substrate with the treated undercoat surface was placed in a vacuum deposition machine, and a fluorine compound was deposited onto the surface where the undercoat had formed. The fluorine compound used was a compound represented by formula (6) with a number-average molecular weight of 5000. The deposition was carried out by impregnating 160 mg of the fluorine compound into steel wool, placing it in a Cu container, and heating it on a resistance boat.

[0062] Next, the silicon substrate on which the fluorine compound was deposited was left to stand for 168 hours in an environment of 25°C and 50% RH. Next, the silicon substrate coated with the fluorine compound was placed in an oven and left to stand for 45 minutes at 120°C.

[0063] Next, the removed silicon substrate was immersed in a fluorine solvent for 30 seconds to clean it and remove any fluorine compounds adhering to the surface. The cleaning process was repeated twice using fresh fluorine solvent, and the solvent was dried to obtain an ink-repellent material to which the fluorine compounds were bonded.

[0064] (Example 2) An ink-repellent component was fabricated using the same method as in Example 1, except that the silicon substrate on which the fluorine compound was deposited was left to stand for 48 hours at a temperature of 25°C and a humidity of 50%RH.

[0065] (Example 3) An ink-repellent component was fabricated in the same manner as in Example 1, except that a 100 nm layer of hafnium oxide was used as a base film instead of tantalum pentoxide using an ALD film deposition apparatus, and the silicon substrate on which a fluorine compound was deposited was left to stand for 48 hours in an environment of 25°C and 50% RH.

[0066] (Comparative Example 1) An ink-repellent component was fabricated using the same method as in Example 1, except that the silicon substrate on which the fluorine compound was deposited was left to stand for 12 hours at a temperature of 25°C and a humidity of 50%RH. Methods for evaluating the substrate and ink-repellent material in the examples and comparative examples will be described.

[0067] (Evaluation 1: Percentage of atomic weights of metal elements after immersion treatment) The substrate surface of the ink-repellent material to which a fluorine compound was bonded was subjected to the following immersion treatment. Subsequently, the ratio of tantalum or hafnium atomic weights (the ratio of tantalum or hafnium atomic weight to the sum of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and tantalum or hafnium atomic weights) was measured, and the amount of coating on the metal oxide substrate was evaluated. (Immersion treatment) (1) Cut a test piece (approximately 700 μm thick, approximately 2 cm square in area) including the surface of the substrate from the ink-repellent material, and place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher (Novec 7200, boiling point 76°C, manufactured by 3M), and immerse the entire test piece in it. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours.

[0068] Furthermore, the XPS measurement conditions for Evaluation 1 were as follows: Measuring device: QuanteraII (product name), manufactured by ULVAC-FI, Inc. X-ray source: AlKα Analysis area: φ200μm Pass energy: 140 eV Total number of times: 10 Detection angle: 45° Detected elements: C, O, F, Si, Ta (or Hf) XPS peaks: C1s, O1s, F1s, Si2p, Ta4f (or Hf4f)

[0069] (Evaluation 2: Evaluation of surface irregularities) The surface morphology of the substrate surface of the ink-repellent material after immersion treatment, to which a fluorine compound was bonded, was measured using an atomic force microscope (Jupiter XR, Oxford Instruments). An SI-DF40 (Hitachi High-Tech Science) cantilever was used, and measurements were taken in tapping mode. As shown in Figure 2(b), the height Z(x,y) values ​​were measured at positions where an arbitrary 20 μm × 20 μm measurement area on the substrate surface was divided into 256 sections in both the x and y directions. Here, at an arbitrary position N o (x n , y n ) and adjacent N a (x n-1 , y n ), N b (x n+1 , y n ), N c (x n , y n-1 ), N d (x n , yn+1 ) was defined. The height at each position is Z o , Z a , Z b , Z c , Z d That's what I decided. Any position N o Regarding m a =|Z o -Z a |, m b =|Z o -Z b |, m c =|Z o -Z c |, m d =|Z o -Z d When we calculate |, m a , m b , m c , m d If all values ​​are 1 nm or less, position N o This was defined as a flat area. Furthermore, the minimum height of the flat areas within the region was defined as Z. min This was done. At any position N o Regarding m oa = Z o -Z a , m ob = Z o -Z b , m oc = Z o -Z c , m od = Z o -Z d When each of these is calculated, m oa , m ob , m oc , m od If all values ​​are positive and at least one of them is greater than 1 nm, then position N o This was defined as a convex portion. Furthermore, among the convex portions within the region, the maximum height was defined as Z. max That's what I decided. The minimum height Z in the flat area, as shown in Figure 2(b), is shown. min , the highest height Z within the convex part max The difference was taken to calculate the distance from the flat part of the ink-repellent film to the apex of the convex part.

[0070] (Rating 3: Ink resistance evaluation) The ink resistance of ink-repellent materials bonded with fluorine compounds was evaluated using the following procedure. Alkaline dye ink (BCI-7C, manufactured by Canon Inc.) was used as the ink. The ink was placed in a PFA container, and the entire surface of the ink-repellent material was immersed in the ink so that it was in contact with the ink, and the container was sealed with a lid. The container was then placed in an oven and maintained at a temperature of 70°C for 30 weeks. After removing the ink-repellent material, it was thoroughly washed with water to remove the ink, and the receding contact angle was measured and evaluated using the following method. A contact angle meter (product name: DM-701, manufactured by Kyowa Interface Science Co., Ltd., analysis software: FAMAS (ver. 3.5.5)) was used. The measurement conditions were as follows. ·Droplet: 2μL (pure water) • Receding contact angle: Calculated using the droplet method. The receding contact angle was measured using the following method: Contact angles were measured at 80 points at 15-second intervals after droplet placement. The following calculations were performed sequentially from time 0 seconds using the contact angle and contact radius (unit: μm) values ​​at a certain time calculated from the above software, and the processes (A) and (B) below were carried out. (A) The value of the contact radius R at time t t , the value of the contact radius R after t+90 seconds t+90 When this is the case, (R t -R t+90 ) 2 The value x was calculated. (B) When the value of x is 200 or less, the process in (A) is repeated, and the contact angle at time t when the value of x first exceeds 200 is defined as the receding contact angle. A: Recessed contact angle is 100° or more B: Recessed contact angle is 95° or more and less than 100° C: Recessed contact angle is 90° or more but less than 95° D: Recessed contact angle is 85° or more and less than 90°

[0071] (Evaluation 4: Evaluation of sliding resistance) The sliding resistance of ink-repellent components bonded with fluorine compounds is evaluated using the following procedure. A high-density felt material (CS-7, manufactured by Taber Industries) is mounted on a friction and wear testing machine (FPR-2100, manufactured by Resca Co., Ltd.) as the sliding material, and a reciprocating sliding test is performed on the surface of the ink-repellent component. The sliding load is 650g, the sliding width is 10mm, the linear speed is 100mm / sec, and the number of sliding cycles is 15,000. The receding contact angle of the surface of the ink-repellent component after sliding was measured and evaluated using the method described in Evaluation 3. The specifications of the ink-repellent materials used in Examples 1-3 and Comparative Example 1 are summarized in Table 1 below.

[0072] [Table 1] The results of evaluations 3 and 4 for the ink-repellent materials in Examples 1 to 3 and Comparative Example 1 are summarized in Table 2 below.

[0073] [Table 2]

[0074] For an ink-repellent material to be practical, it must have a contact angle of 90° or more. Therefore, the ink-repellent materials according to Examples 1 to 3, which have A to C ratings for both ink resistance and sliding resistance, can be said to have superior practical characteristics compared to the ink-repellent material according to Comparative Example 1.

[0075] This embodiment includes the following configurations and methods. (Composition 1) An ink-repellent member having a substrate containing a metal oxide, wherein a fluorine compound is bonded to the surface of the substrate, The covalent bond index between the metal element and oxygen in the aforementioned metal oxide is 0.44 or less. An ink-repellent material characterized in that, when the surface of the substrate is measured by X-ray photoelectron spectroscopy after the ink-repellent material has undergone the following immersion treatments (1) and (2), the ratio of the atomic weight of the metal element to the sum of the amount of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and the atomic weight of the metal element is 1 atm% or less. (Immersion treatment) (1) Cut out a test piece from the ink-repellent material including the surface of the base material, place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, and immerse the entire test piece in it. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours. (Configuration 2) The ink-repellent member according to configuration 1, characterized by having an uneven structure containing the fluorine compound. (Composition 3) The ink-repellent member according to configuration 2, characterized in that the uneven structure has a convex portion and a flat portion, and the distance between the apex of the convex portion and the flat portion is 20 nm or more. (Composition 4) The ink-repellent member according to any one of the configurations 1 to 3, characterized in that the aforementioned metal element is tantalum. (Composition 5) The ink-repellent member according to any one of configurations 1 to 4, characterized in that the fluorine compound has a main chain having a perfluoropolyether structure and a perfluoromethyl group at its terminus. (Composition 6) The ink-repellent member according to any one of configurations 1 to 5, characterized in that the fluorine compound has at least one of the structures represented by the following formula (2), the following formula (3), the following formula (4), and the following formula (5). [ka] [ka] [ka] [Chemical formula] (In formulas (2), (3), (4), and (5), n1, n2, n3, and n4 each independently represent an integer of 1 or more.) (Configuration 7) A method for manufacturing a non-ink member having a base layer containing a metal oxide and a fluorine compound bonded to the surface of the base layer, where the covalent bond index between the metal element and oxygen of the metal oxide is 0.44 or less, characterized by including the following steps (1), (2), (3), and (4). (1) A step of plasma-treating the surface of the base layer in an atmosphere with an oxygen concentration of 50% by volume or more (2) A step of applying and dehydrating and condensing a fluorine compound having a reactive silyl group represented by the following formula (1) on the surface of the base layer plasma-treated in the step (1) *-Si(Y 1 ) n (OR) m (1) (In formula (1), n and m are integers from 0 to 3, and n + m = 3. Y 1 each independently represents an alkyl group, a chloro group, or a bromo group. R each independently represents a hydrogen atom or an alkyl group. * indicates the bonding position in the fluorine compound.) (3) A step of allowing the fluorine compound applied to the base layer in the step (2) to exist for 48 hours or more in an environment of temperature 25 ± 2°C and humidity 50 ± 10% RH to bond to the surface of the base layer (4) A step of heating the fluorine compound and the surface of the base layer after the step (3) (Configuration 8) In the step (3), the method for manufacturing a non-ink member according to Configuration 7, characterized in that the fluorine compound is allowed to exist for 96 hours or more in an environment of temperature 25 ± 2°C and humidity 50 ± 10% RH to bond to the surface of the base layer. (Configuration 9) A method for manufacturing an ink-repellent member according to configuration 7 or 8, characterized in that in step (4) above, the fluorine compound and the surface of the substrate are heated to 100°C or higher to cause dehydration condensation. (Composition 10) A method for manufacturing an ink-repellent member according to any one of the configurations 7 to 9, characterized in that the oxygen concentration in step (1) is 75% by volume or more. (Composition 11) Having an ink-repellent member as described in any one of configurations 1 to 6, An inkjet head characterized in that a discharge port for discharging liquid is arranged on the side of the ink-repellent member where the base material is provided. (Composition 12) A method for manufacturing an article, which includes a step of ejecting liquid using the inkjet head described in configuration 11, A method for manufacturing an article, characterized in that the liquid is an ink containing a functional material for forming a functional thin film or a functional element. [Explanation of symbols]

[0076] 1...First channel substrate / 2...Second channel substrate / 3...Adhesive layer / 4...Discharge port / 5...Discharge energy generating element / 6...Orifice plate / 6a...Orifice surface / 7...Electrode / 8...First through-channel / 9...Second through-channel / 10...Liquid channel / 19...Third through-channel / 100...Inkjet head

Claims

1. An ink-repellent member having a substrate containing a metal oxide, wherein a fluorine compound is bonded to the surface of the substrate, The covalent bond index between the metal element and oxygen in the aforementioned metal oxide is 0.44 or less. An ink-repellent material characterized in that, when the surface of the substrate is measured by X-ray photoelectron spectroscopy after the ink-repellent material has undergone the following immersion treatments (1) and (2), the ratio of the atomic weight of the metal element to the sum of the amount of carbon atoms, oxygen atoms, fluorine atoms, silicon atoms, and the atomic weight of the metal element is 1 atm% or less. (Immersion treatment) (1) Cut out a test piece from the ink-repellent material including the surface of the base material, place it in a sealable container containing a fluorine solvent with a boiling point of 60°C or higher, and immerse the entire test piece in it. (2) After immersion in (1), maintain in a sealed state at 60°C for 4 hours.

2. The ink-repellent member according to claim 1, characterized in having an uneven structure containing the fluorine compound.

3. The ink-repellent member according to claim 2, characterized in that the uneven structure has a convex portion and a flat portion, and the convex portion has a distance of 20 nm or more between the apex of the convex portion and the flat portion.

4. The ink-repellent member according to claim 1, characterized in that the aforementioned metal element is tantalum.

5. The ink-repellent member according to claim 1, characterized in that the fluorine compound has a main chain having a perfluoropolyether structure and has a perfluoromethyl group at its terminus.

6. The ink-repellent member according to claim 1, characterized in that the fluorine compound has at least one of the structures represented by the following formula (2), the following formula (3), the following formula (4), and the following formula (5). 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 (In equations (2), (3), (4), and (5), n1, n2, n3, and n4 each independently represent an integer greater than or equal to 1.)

7. A method for manufacturing an ink-repellent member having a base containing a metal oxide, wherein a fluorine compound is bonded to the surface of the base, The covalent bond index between the metal element and oxygen in the aforementioned metal oxide is 0.44 or less. A method for manufacturing an ink-repellent material, characterized by comprising the following steps (1), (2), (3), and (4). (1) A process of plasma treatment of the surface of the substrate in an atmosphere with an oxygen concentration of 50 volume percent or more. (2) A step of applying a fluorine compound having a reactive silyl group represented by the following formula (1) onto the surface of the substrate that has been plasma treated in step (1) and dehydrating and condensing it. *-Si(Y １ ) ｎ (OR) ｍ (1) (In equation (1), n ​​and m are integers from 0 to 3, and n + m = 3. Y １ Each of the following independently represents an alkyl group, a chloro group, or a bromo group. Each of the following independently represents a hydrogen atom or an alkyl group. * indicates the bond position in the fluorine compound. (3) A step of bonding the fluorine compound applied to the substrate in step (2) to the surface of the substrate by allowing it to remain in an environment of 25±2°C and 50±10% RH for 48 hours or more. (4) A step of heating the surface of the fluorine compound and the substrate after step (3).

8. The method for manufacturing an ink-repellent material according to claim 7, characterized in that in step (3) above, the fluorine compound is allowed to bond to the surface of the substrate by being present in an environment with a temperature of 25±2°C and a humidity of 50±10%RH for 96 hours or more.

9. The method for manufacturing an ink-repellent material according to claim 7, characterized in that in step (4) above, the fluorine compound and the surface of the substrate are heated to 100°C or higher to cause dehydration condensation.

10. The method for manufacturing an ink-repellent member according to claim 7, characterized in that the oxygen concentration in step (1) is 75% by volume or more.

11. Having an ink-repellent member according to any one of claims 1 to 6, An inkjet head characterized in that a discharge port for discharging liquid is arranged on the side of the ink-repellent member where the base material is provided.

12. A method for manufacturing an article, comprising the step of discharging a liquid using the inkjet head described in claim 11, A method for manufacturing an article, characterized in that the liquid is an ink containing a functional material for forming a functional thin film or a functional element.

Images