Ink-repellent member, method of producing ink-repellent member, ink jet head, and method of producing article

Abstract

To provide: an ink-repellent member that is excellent in both ink resistance and sliding resistance; and an inkjet head.SOLUTION: There is provided an ink-repellent member including an underlying portion that contains a tantalum oxide, and has a fluorine compound bonded to a surface of the underlying portion via a Ta-O-Si bond, wherein, when a ratio of a fluorine atom amount with respect to a total of a carbon atom amount, an oxygen atom amount, the fluorine atom amount, a silicon atom amount, and a tantalum atom amount in measurement by X-ray photoelectron spectroscopy of the surface after the ink-repellent member is subjected to an immersion treatment (1) and (2) is represented by F, the F is 50 atm% or more. (Immersion Treatment)(1) a test piece including the surface is cut out of the ink-repellent member, is placed in a sealable container containing a fluorine solvent containing a hydrofluoroether having a boiling point of 60°C. or more, and is immersed in the fluorine solvent so that the test piece is entirely immersed therein; and (2) the test piece is maintained at 60°C. for 4 hours in a sealed state after the immersion in (1).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an ink-repellent member and an inkjet head.

Background Art

[0002] As a device for ejecting ink (hereinafter referred to as an inkjet head), there are known a bubble jet (registered trademark) 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 are ejected from the ink ejection port while maintaining straightness along a predetermined direction. However, if droplet residues adhere to the orifice plate surface around the ejection port, when ejecting ink droplets, the ink droplets will be dragged by the residues, resulting in a deviation in the ejection direction, and the ink droplets may fly out of the predetermined direction. Therefore, in order to suppress the adhesion of droplet residues around the ink ejection port, an ink-repellent film is provided around the ink ejection port and used as an ink-repellent member.

[0003] For example, Patent Document 1 discloses that a base made of an inorganic oxide is provided on the orifice plate surface, 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 orifice plate surface 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

Non-Patent Documents

[0006] [Non-Patent Document 1] "Surface Technology", Surface Technology Association, 1998, Vol. 49, No. 2, pp. 191-194 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] When bonding a fluorine-containing silane coupling agent, it is common to use silicon oxide as the substrate. However, as in Patent Document 1, tantalum oxide may be used for the purpose of liquid resistance.

[0008] However, it is known that the Ta-O bond formed when bonding a silane coupling agent to tantalum oxide has a lower covalent bond character (higher ionic bond character) than the Si-O bond formed when using silicon oxide as the substrate (Non-Patent Document 1). Therefore, the inventors have found that the reactivity between the substrate and the silane coupling agent is low, and there is a problem that the ability of the ink repellent member decreases due to long-term ink contact and sliding. Therefore, even when using tantalum oxide as the substrate, an ink repellent member excellent in slidability and ink resistance has been demanded. [Means for Solving the Problems]

[0009] According to one aspect of the present invention, there is provided an ink repellent member having a substrate containing tantalum oxide, wherein a fluorine compound is bonded to the surface of the substrate via a Ta-O-Si bond. When the surface after performing the following dipping treatments (1) and (2) on the ink repellent member is measured by X-ray photoelectron spectroscopy, when the ratio of the fluorine atomic weight to the total of the carbon atomic weight, oxygen atomic weight, fluorine atomic weight, silicon atomic weight, and tantalum atomic weight is F, an ink repellent member characterized in that F is 50 atm% or more is provided. (Dipping Treatment) (1) Cut out a test piece including the surface from the ink repellent member, place it in a sealable container containing a fluorine solvent containing hydrofluoroether with a boiling point of 60 °C or higher, and immerse it so that the entire test piece is submerged. (2) After the immersion in (1), maintain it at 60 °C for 4 hours in a sealed state.

[0010] Further, according to one aspect of the present invention, there is provided an ink repellent member having a base containing an oxide of tantalum, and a fluorine compound bonded to the surface of the base via a Ta-O-Si bond, wherein the root mean square slope (Rdq) on the surface is 0.08 or less.

[0011] Further, according to one aspect of the present invention, there is provided a method for manufacturing the above ink repellent member, which is characterized by including the following steps (1) and (2). (1) A step of plasma-treating the surface of the base in an atmosphere with an oxygen concentration of 50% by volume or more (2) A step of applying a fluorine compound having a reactive silyl group represented by the following formula (1) on the surface of the base plasma-treated in the step (1) and performing dehydration condensation *-Si(Y 1 ) n (OR) m (1) (In the 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.)

[0012] Further, according to one aspect of the present invention, there is provided an inkjet head characterized by having the above ink repellent member. Further, according to another aspect of the present invention, there is provided a method for manufacturing an article, which is characterized by including a step of discharging a liquid using the above 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

[0013] According to the present invention, it is possible to provide a ink-repellent member excellent in both slidability resistance and ink resistance, and an inkjet head.

Brief Description of Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0015] With reference to the drawings, an ink-repellent member, an inkjet head, etc., which are embodiments of the present invention, will be described. Hereinafter, it will be described as "ink repellency", "ink-repellent member", etc., but it may be read as "water repellency", "water-repellent member" assuming an aqueous ink. In addition, when implementing the present invention, it is not always necessary to limit the type and use of the liquid, so in the following description, "ink repellency", "ink-repellent member" may be read as "liquid repellency", "liquid-repellent member". The embodiments shown below are examples, and for example, those skilled in the art can appropriately change and implement the detailed configurations without departing from the gist of the present invention.

[0016] In the following descriptions of embodiments and examples, unless otherwise specified, elements with the same reference numerals have the same functions. Also, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the endpoints XX (lower limit) and YY (upper limit) unless otherwise specified. When a numerical range is described stepwise, the upper and lower limits of each numerical range can be arbitrarily combined.

[0017] In this specification, the liquid to be handled may be described as "ink", but the ink is not limited to the liquid for forming characters and images. For example, it may be a liquid containing a functional material for forming a functional thin film such as an electrode or an optical filter, or a functional element such as an organic EL element.

[0018] The ink-repellent member according to the present invention has a base containing an oxide of tantalum, and a fluorine compound is bonded to the surface of the base via a Ta-O-Si bond. When the surface of the base (the surface of the ink-repellent member) after performing the following immersion treatments (1) and (2) on the ink-repellent member is measured by X-ray photoelectron spectroscopy, the proportion of the amount of fluorine atoms to the total amount of the amount of carbon atoms, the amount of oxygen atoms, the amount of fluorine atoms, the amount of silicon atoms, and the amount of tantalum atoms is defined as F, and the ink-repellent member is characterized in that F is 50 atm% or more. (Immersion treatment) (1) Cut out a test piece including the surface of the base (the surface of the ink-repellent member) from the ink-repellent member, put it into a sealable container containing a fluorine solvent containing hydrofluoroether with a boiling point of 60°C or higher, and immerse it so that the entire test piece is submerged. (2) After the immersion in (1), maintain it at 60°C for 4 hours in a sealed state.

[0019] In this specification, the ink-repellent member refers to a member including a base having a surface to which a fluorine compound is chemically bonded (a member including a base to which a fluorine compound is chemically bonded to its surface).

[0020] The inventors have repeatedly studied to obtain an ink-repellent member that can maintain long-term ink resistance and sliding resistance even when a tantalum oxide is used as a base. As a result, they have found that the above object can be achieved by subjecting the tantalum oxide to plasma treatment in an oxygen atmosphere and then bonding a fluorine compound thereto.

[0021] Since tantalum oxide has high surface activity, hydrocarbons in the air and the like are likely to adsorb on the surface. Therefore, in order to form a hydroxy group (hydroxyl group), which is a reactive group, on the surface of the base, it seemed preferable to perform treatment in an argon atmosphere with a large atomic radius and high collision energy. However, as a result of the inventors' intensive studies, it has been found that more hydroxy groups are formed by plasma treatment in an oxygen atmosphere. Furthermore, it has been found that the surface slope of the base surface after plasma treatment in an oxygen atmosphere is gentle. Since the amount of hydroxy groups is large, the bonding amount of the fluorine compound to the base increases, and since the slope is gentle, the fluorine compound is effectively arranged against wiping without being buried in the surface recesses. It is considered that an ink-repellent member excellent in ink resistance and sliding resistance can be realized thereby.

[0022] (Inkjet head) First, an inkjet head according to an embodiment of the present invention can be an inkjet head having the ink-repellent member according to the present invention. The configuration of the inkjet head according to this embodiment will be described. FIG. 1(a) is a top view of an inkjet head 100 according to this embodiment, and FIG. 1(b) is a bottom view of the inkjet head 100. Further, FIG. 1(c) is a partial perspective view for showing a part of a cross section cut along the A-A' line shown in FIGS. 1(a) and 1(b).

[0023] The inkjet head 100 can include a first flow path substrate 1 as a first member, a second flow path substrate 2 as a second member, an adhesive layer 3, a discharge port 4, a discharge energy generating element 5, an orifice plate 6 (ink repellent member), an electrode 7, and an ink tank chamber. Note that the ink tank chamber is not shown in FIGS. 1(a) to 1(c). Also, among the components of the inkjet head, components not directly related to the description of the present invention (for example, electric circuits and wirings) are not shown.

[0024] The first flow path substrate 1 and the second flow path substrate 2, the first flow path substrate 1 and the orifice plate 6, and the second flow path substrate 2 and the ink tank chamber are joined via the adhesive layer 3 and integrated to form a flow path structure. In the flow path structure, a first through-flow path 8 and a second through-flow path 9 are formed, and these communicate with each other to form an ink supply path. Note that in FIG. 1(c), only a part of the adhesive layer 3 is shown for convenience of illustration.

[0025] Ink is supplied from the ink tank chamber through the second through-flow path 9 formed in the second flow path substrate 2 and the first flow path substrate 1 to the liquid flow path 10, and discharge energy is imparted by the discharge energy generating element 5, and then discharged from the discharge port 4. The ink that has not been discharged from the discharge port 4 flows back to the ink tank chamber through the first through-flow path 8 formed in the first flow path substrate 1 and the third through-flow path 19 (circulation return path) formed in the second flow path substrate 2.

[0026] The orifice plate 6 has a plurality of discharge ports 4, but the arrangement method (number and position) of the discharge ports 4 is not limited to the illustrated example. On the outer surface of the orifice plate 6, that is, the orifice surface 6a on the side opposite to the liquid flow path 10, a fluorine compound is bonded to the surface of the base layer described later. On the first flow path substrate 1, at positions corresponding to the respective discharge ports 4, a discharge energy generating element 5 for discharging liquid is provided, and the discharge energy generating element 5 is driven in response to an electric signal transmitted from the outside via the electrode 7. As the discharge energy generating element 5, for example, an electrothermal conversion element or a piezoelectric element is preferably used. Silicon is suitable as the material of the base material of the orifice plate 6, but other materials such as silicon carbide, silicon nitride, various glasses 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 addition, in the present embodiment, the orifice plate is used as a non-ink member, but the inkjet head itself may be used as a non-ink member.

[0027] (Base layer) The base layer provided on the outer surface (orifice surface 6a) of the orifice plate 6 shown in FIG. 1 is composed of an inorganic oxide. The base layer forms a hydroxy group on the surface and can form a chemical bond with a fluorine compound (fluorine-containing silane coupling agent) having a reactive silyl group. By chemically bonding, the fluorine compound can improve the adhesion in the base layer. The base layer can be formed on the base material as a base film or a base layer, but when the base material itself (bulk material) is composed of an inorganic oxide, the base material itself may be used as the base layer.

[0028] In the present invention, the base layer contains tantalum oxide as an inorganic oxide. Tantalum oxide forms compounds with oxidation numbers of +2 to +5, and among these, tantalum pentoxide is preferred from the viewpoint of forming a large number of hydroxy groups as reaction sites. In addition to tantalum oxide, oxide materials such as silicon oxide, zirconia, alumina, titania, hafnia, cerium oxide, tungsten oxide, niobium oxide, and yttrium oxide may further be included.

[0029] As a base containing tantalum oxide, for example, a base film can be formed on a substrate (e.g., silicon) by a sputtering method, an ion assist evaporation method, an atomic layer deposition method (ALD), or the like. Among these, from the viewpoint of forming a high-density film, it is preferable to use the ALD method. When the density becomes high, the ink resistance to alkaline ink is further improved.

[0030] When providing a base film as a base on a substrate, silicon is generally used as the substrate of the lower layer of the base film. In this case, from the viewpoint of protecting silicon from ink, the film thickness of the base film is preferably 10 nm or more, and more preferably 50 nm or more. Also, from the viewpoint of suppressing cohesive failure during sliding, it is preferably 300 nm or less, and more preferably 200 nm or less.

[0031] (Surface treatment of the base) A method for manufacturing a ink repellent member according to an embodiment of the present invention is a method for manufacturing an ink repellent member having a base containing tantalum oxide and a fluorine compound bonded to the surface of the base via a Ta-O-Si bond, and is characterized by including the following steps (1) and (2). (1) A step of plasma-treating the surface of the base without the bonded fluorine compound 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 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.)

[0032] In the present invention, it is preferable to perform plasma treatment on the surface of the substrate in an oxygen atmosphere. As a result of investigations by the present inventors, even when treated in an atmosphere of either oxygen or argon, the contact angle after treatment is in a low state (for example, static contact angle < 5°). However, it has been found that when treated in an oxygen atmosphere, more hydroxy groups can be formed than when treated in an argon atmosphere.

[0033] For mechanism investigation, the surface after plasma treatment was measured by X-ray photoelectron spectroscopy (XPS), and the ratio of valence states +1 to +5 was calculated from the analysis of Ta 4f. As a result, it was confirmed that when treated in an argon atmosphere, the ratio of +5 valence decreased (95% before treatment, 85% after treatment). On the other hand, when treated in an oxygen atmosphere, no decrease in the ratio of +5 valence was confirmed. Therefore, it is presumed that when performing plasma treatment on tantalum oxide, a large number of hydroxy groups can be formed by treating in an oxygen atmosphere.

[0034] For example, when performing plasma treatment in a mixed atmosphere of another gas such as argon and oxygen, the oxygen concentration 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 also be performed in an atmosphere containing only oxygen (oxygen concentration is 100% by volume). When the oxygen concentration is 50% by volume or more, sufficient hydroxy groups are formed.

[0035] 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.

[0036] The amount of hydroxy groups on the surface of the substrate after plasma treatment can be quantified by treating the surface of the substrate with a low molecular weight silane coupling agent having fluorine and measuring the fluorine atomic weight by X-ray photoelectron spectroscopy. At this time, the ratio of the fluorine atomic weight can be calculated in the same manner as the evaluation of the bonding amount of the fluorine compound described later, and the amount of hydroxy groups can be evaluated using that value.

[0037] Furthermore, the surface shape of the substrate after plasma treatment was analyzed. As a result, although the arithmetic mean roughness (Ra) did not change depending on the atmosphere, it was found that the surface inclination (root mean square slope Rdq) became gentler when plasma treatment was performed in an oxygen atmosphere compared to the case of treatment in an argon atmosphere. Although the detailed reason is unknown, it is presumed that when the active species generated in the oxygen atmosphere react with the tantalum oxide, the surface of the tantalum oxide is uniformly and softly surface-treated to such an extent that it is not roughened.

[0038] FIG. 2(a) is a schematic diagram showing the state of the ink repellent member according to an embodiment of the present invention, and (b) is a schematic diagram showing the state of the ink repellent member according to the prior art. In the ink repellent member 21 according to the present embodiment, a fluorine compound is chemically bonded to the surface 23 of the substrate 22. When the surface inclination is gentle, when the fluorine compound is chemically bonded to the substrate, it can be bonded at a position and angle that are not buried in the surface recesses, and as a result, it is considered that a state in which effective sliding resistance can be exhibited against wiping can be realized. On the other hand, in the ink repellent member 31 according to the prior art, although a fluorine compound is chemically bonded to the surface 33 of the substrate 32, the inclination is steeper than that of the ink repellent member 21, so the fluorine compound is likely to be buried in the surface recesses, and the bonding amount of the fluorine compound is also small.

[0039] Rdq evaluates the magnitude of the local inclination angle and quantifies the ruggedness of the surface unevenness. Rdq can be calculated, for example, by measuring the surface with an atomic force microscope (AFM).

[0040] An ink repellent member according to an embodiment of the present invention is an ink repellent member having a substrate containing tantalum oxide, wherein a fluorine compound is bonded to the surface of the substrate via a Ta-O-Si bond, and the root mean square slope (Rdq) at the surface of the substrate (the surface of the ink repellent member) is 0.08 or less.

[0041] The Rdq of the surface of the substrate bonded with the fluorine compound is preferably 0.08 or less, more preferably 0.07 or less. When it is 0.08 or less, the sliding resistance is improved, which is preferable.

[0042] When using tantalum oxide as the substrate, by performing plasma treatment in an oxygen atmosphere, the amount of hydroxy groups as reactive groups can be increased, and the fluorine compound is less likely to be buried in the concave portions, enabling a state where the effect is easily exhibited. Thus, an ink-repellent member excellent in ink resistance and sliding resistance can be realized.

[0043] (Fluorine compound) The fluorine compound used in the ink-repellent member has a linear main-chain structure. Among the terminals on both sides of the main chain, one terminal forms a chemical bond (Ta-O-Si) with the hydroxy group on the surface of the tantalum oxide of the substrate. In order to form a Ta-O-Si bond, the fluorine compound used in the production of the ink-repellent member has at least one reactive silyl group represented by the following formula (1). By having a reactive silyl group at one terminal, the reaction between fluorine compounds can be suppressed. *-Si(Y 1 ) n (OR) m (1) In formula (1), n and m are integers from 0 to 3, and n + m = 3. For example, m can represent 3 and n can represent 0. 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. Y 1 preferably represents a methyl group. When the carbon number of Y 1 is small, it is easy to suppress the decrease in reactivity due to steric hindrance. R preferably represents a methyl group because the hydrolysis of the fluorine compound is fast and the reaction becomes fast.

[0044] Also, the other terminal of the fluorine compound preferably has a perfluoromethyl structure (perfluoromethyl group). The perfluoromethyl structure has a small surface free energy and can exhibit high ink repellency.

[0045] 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.

[0046] That is, the preferable structure of the fluorine compound used for manufacturing the ink repellent member can be represented by the following formula (10).

Chemical formula

[0047] The fluorine compound preferably has at least one of the repeating structures represented by the following formula (2), the repeating structure represented by the following formula (3), the repeating structure represented by the following formula (4), and the repeating structure represented by the following formula (5).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0048] In addition, in formula (2), formula (3), formula (4), and formula (5), n1, n2, n3, and n4 each independently represent an integer of 1 or more.

[0049] Preferable specific examples of the fluorine compound 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).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0050] As the fluorine compound contained in the ink repellent member, it is preferably a fluorine compound having a main chain with a perfluoropolyether structure and a perfluoromethyl group at the end. That is, the preferable structure of the fluorine compound in the state where the fluorine compound is chemically bonded to the surface of the substrate via a Ta-O-Si bond can be represented by the following formula (11).

Chemical formula

[0051] The number average molecular weight of the fluorine compound is preferably 4,000 or more. The number average molecular weight of the fluorine compound can be calculated, for example, 19 by measuring 19F-NMR and calculating from the integration ratio with the terminal perfluoromethyl group (CF3 group).

[0052] (Method for producing the ink repellent member) Next, a method for bonding a fluorine compound to the surface of a substrate containing a tantalum oxide will be described. The fluorine compound can be bonded by a silane coupling treatment. An example is described below.

[0053] First, for example, a substrate such as an orifice plate is formed with a substrate that is a base film containing a tantalum oxide. Examples of forming the tantalum oxide as the base film include a method of forming by atomic layer deposition (ALD).

[0054] Next, a hydroxy group is formed on the surface of the substrate by the above-described plasma treatment.

[0055] Next, a fluorine compound is applied to the surface of the substrate on which the hydroxy group is formed. There are no particular restrictions on the application method, and examples include vacuum evaporation, thermal evaporation, spray coating, spin coating, and dip coating.

[0056] Subsequently, the alkoxysilyl group or halogenated silyl group at the end of the fluorine compound is hydrolyzed to be converted into a silanol group (Si-OH group). Then, a dehydration condensation reaction is performed between the silanol group of the fluorine compound and the hydroxy group formed on the substrate to form a Ta-O-Si bond.

[0057] Hydrolysis occurs by exposure to moisture and also by the adsorbed water present on the substrate surface. The dehydration condensation reaction occurs even at room temperature, but can be accelerated by raising the temperature (for example, 100°C to 120°C). Especially when the substrate is a tantalum oxide, the covalent bond property of the Ta-O bond in the Ta-O-Si bond is small, and the reaction is difficult to occur. Therefore, in the reaction at room temperature, the reaction energy required for bonding is insufficient, and the reaction between fluorine compounds (Si-O-Si bond) may easily occur. In order to make the bonding amount of the fluorine compound on the substrate sufficiently large, it is preferable to heat and react the applied fluorine compound at a high temperature to promote the bonding between the fluorine compound and the substrate. Specifically, for example, it is preferable to heat and dehydrate and condense the applied fluorine compound so that it reaches 100°C or higher.

[0058] Regarding the reaction time, it can be appropriately selected according to the temperature. For example, at room temperature, it is about 10 hours, and under the condition of 120 °C, the reaction time is about 1 hour.

[0059] Subsequently, washing is performed to remove the remaining unbound fluorine compound. There is no particular limitation on the washing method. For example, the ink repellent member may be immersed in a fluorine solvent that is compatible with the fluorine compound. Wash until it can be confirmed visually that no fluorine compound remains on the base material.

[0060] The thickness of the fluorine compound is preferably 5 nm or more, and more preferably 10 nm or more. After drying the fluorine solvent, it can be used for evaluation of the bonding amount, ink resistance, and sliding resistance of the fluorine compound.

[0061] (Bonding amount of fluorine compound) In the ink repellent member according to one embodiment of the present invention, the ratio F of the fluorine atomic weight measured as described below is 50 atm% (atomic percentage) or more. The ratio F of the fluorine atomic weight corresponds to the bonding amount of the fluorine compound on the surface of the ink repellent member. After performing the following immersion treatments (1) and (2) on the ink repellent member to which the fluorine compound is bonded, the surface (the surface of the base material) of the ink repellent member is measured by X-ray photoelectron spectroscopy, and the ratio F of the fluorine atomic weight to the total of the carbon atomic weight, oxygen atomic weight, fluorine atomic weight, silicon atomic weight, and tantalum atomic weight is calculated. (Immersion treatment) (1) Cut out a test piece including the surface of the base material from the ink repellent member, and place it in a sealable container containing a fluorine solvent containing hydrofluoroether having a boiling point of 60 °C or higher, and immerse it so that the entire test piece is immersed. (2) After the immersion in (1), maintain at 60 °C for 4 hours in a sealed state.

[0062] The XPS measurement conditions can be as follows. Measuring device: QuanteraII (trade name), manufactured by ULVAC-PHI, Inc. X-ray source: AlKα Analysis area: φ200μm Pass energy: 140eV Number of integrations: 10 Detection angle: 45° Detected elements: C, O, F, Si, Ta XPS peaks: C1s, O1s, F1s, Si2p, Ta4f

[0063] Hydrofluoroether is a compound composed of carbon atoms, fluorine atoms, hydrogen atoms and ether bonds (-O-), and it only dissolves fluorine compounds and has no corrosiveness. Therefore, by the above treatment, although it is not chemically bonded to the substrate, the fluorine compounds that could not be completely removed in the cleaning process can be removed. That is, by performing the above dipping treatment, only the fluorine compounds actually chemically bonded to the substrate can be quantified.

[0064] As an example, FIG. 3 shows the change in the ratio of the amount of fluorine atoms when the ink-repellent member according to an embodiment of the present invention used in Example 1 below and the ink-repellent member according to the prior art used in Comparative Example 3 were subjected to the above dipping treatment. The ratio of the amount of fluorine atoms is the ratio of the amount of fluorine atoms to the total of the amount of carbon atoms, the amount of oxygen atoms, the amount of fluorine atoms, the amount of silicon atoms, and the amount of tantalum atoms.

[0065] The ratio of the amount of fluorine atoms after the cleaning process (corresponding to a processing time of 0 h in FIG. 3) is the same, but it can be seen that the F of the ink-repellent member according to the prior art has decreased due to the above dipping treatment. On the other hand, it can be seen that the F of the ink-repellent member according to this embodiment produced in Example 1 is maintained when maintained for 4 h. Since the removal is completed by treatment for 3 h or more, it can be evaluated by treatment for 4 h.

[0066] Since unreacted fluorine compounds can also contribute to high durability, it is common in practical use to use them without actively removing them. However, unreacted fluorine compounds diffuse into the ink, for example, during ink contact and are removed over time. As a result, a substrate with low liquid repellency is exposed, leading to deterioration of the ink repellent function. Even if the ratio of the fluorine atomic weight was the same before the above treatment, the actually bonded amount to the substrate changes depending on the film-forming process. Therefore, by realizing a large ink repellent member with F after the above treatment, an ink repellent member excellent in ink resistance can be obtained.

[0067] F after the dipping treatment is preferably 50 atm% or more, and more preferably 52 atm% or more. When it is 50 atm% or more, the ink resistance becomes sufficient.

[0068] There are no particular restrictions on the fluorine solvent containing hydrofluoroether used for the dipping treatment. Examples of commercially available ones include Novec (registered trademark) 7200 (boiling point 76 °C, manufactured by 3M, structure C4F9OC2H5), Sumitex Solvent 72 (boiling point 76 °C, manufactured by Sumitomo Mining Lubricants Co., Ltd.), SOLBLE RN2000 (boiling point 76 °C, Solvex) (all contain compounds with the same structure as Novec 7200 as the main component), etc. The fluorine solvent containing hydrofluoroether may be hydrofluoroether itself (hydrofluoroether is 100%).

[0069] (Method for manufacturing an article using an ink repellent member) A method for manufacturing an article according to an embodiment of the present invention is a method for manufacturing an article characterized by including a step of discharging a liquid using the above-described ink repellent member (for example, an inkjet head), wherein the liquid is an ink containing a functional material for forming a functional thin film or a functional element.

Examples

[0070] Specific examples and comparative examples are given below. (Example 1) On a silicon substrate with a diameter of 3 inches, 100 nm of tantalum pentoxide was deposited using an ALD film deposition apparatus. Next, the silicon substrate with the tantalum pentoxide formed as the underlying film was placed in the chamber of a plasma processing apparatus to process the surface of the underlying film. 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: 120 W). This state was maintained for 300 seconds.

[0071] Subsequently, the silicon substrate with the surface of the underlying film processed was placed in a vacuum evaporator, and a fluorine compound was deposited on the surface where the underlying film was formed. As the fluorine compound, a compound represented by formula (6) with a number average molecular weight of 5000 was used. The deposition was carried out by placing 160 mg of the fluorine compound impregnated in steel wool in a Cu container and heating it on a resistance boat.

[0072] Subsequently, the silicon substrate with the fluorine compound deposited was placed in an oven and left standing in an environment of 120 °C for 45 minutes. Subsequently, the taken-out silicon substrate was immersed in a fluorine solvent for 30 seconds for washing to remove the fluorine compound adhering to the surface. The washing was repeated twice using fresh fluorine solvent, the solvent was dried, and an ink-repellent member with the fluorine compound bonded was obtained.

[0073] (Examples 2 to 5, Comparative Examples 1 to 3) Except that the plasma treatment of the underlying film and the dehydration condensation conditions were changed to the conditions shown in Table 1, the ink-repellent members according to each example and comparative example were produced in the same manner as in Example 1. A method for evaluating the underlying film and the ink-repellent member according to the examples and comparative examples will be described.

[0074] (Evaluation 1: Amount of hydroxyl groups in the underlying film) A test piece (thickness: approximately 700 μm, size: approximately 2 cm square) containing a plasma-treated tantalum pentoxide substrate (unbonded fluorine compound) was cut out and placed in a PFA container together with a vial containing (3,3,3-trifluoropropyl)dimethylchlorosilane (manufactured by Gelest). The vial was covered and sealed so that the test piece was immersed in (3,3,3-trifluoropropyl)dimethylchlorosilane, and left standing at 30 °C for 20 hours. The surface of the substrate of the taken-out test piece was measured by X-ray photoelectron spectroscopy (XPS), and the amount of hydroxy groups was evaluated by calculating the ratio of the fluorine atomic weight to the total of the carbon atomic weight, oxygen atomic weight, fluorine atomic weight, silicon atomic weight, and tantalum atomic weight.

[0075] XPS Measurement Conditions Measuring device: Quantera II (trade name), manufactured by ULVAC-PHI, Inc. X-ray source: AlKα Analysis area: φ200 μm Pass energy: 140 eV Integration times: 10 Detection angle: 45° Detected elements: C, O, F, Si, Ta XPS peaks: C1s, O1s, F1s, Si2p, Ta4f

[0076] Note that the amount of hydroxy groups was evaluated according to the following criteria. A: Ratio of fluorine atomic weight is 5.0 atm% or more B: Ratio of fluorine atomic weight is 4.0 atm% or more and less than 5.0 atm% C: Ratio of fluorine atomic weight is 3.0 atm% or more and less than 4.0 atm% D: Ratio of fluorine atomic weight is 2.0 atm% or more and less than 3.0 atm% E: Ratio of fluorine atomic weight is less than 2.0 atm% When evaluating the amount of hydroxy groups on the surface of the fluorine compound-unbonded substrate of Example 1, the ratio of the above fluorine atomic weight was 5.2 atm%, and it was evaluated as A.

[0077] (Evaluation 2: Surface shape (arithmetic mean roughness Ra and root mean square slope Rdq) of the fluorine compound-unbonded substrate and the substrate of the ink repellent member) The surface shapes of the substrate after plasma treatment (unbonded fluorine compound) and the substrate of the ink-repellent member with the fluorine compound bonded were measured using an atomic force microscope (L-traceII, manufactured by Hitachi High-Tech Science Corporation). SI-DF40 (manufactured by Hitachi High-Tech Science Corporation) was used as the cantilever, and the measurement was performed in tapping mode. As shown in Fig. 4, the height Z(x, y) values at positions where an arbitrary 500 nm × 500 nm measurement area on the surface of the substrate was divided into 256 parts in the x-direction and y-direction were measured respectively.

[0078] Ra and Rdq were calculated based on the method specified in JIS B0601. The calculation method of Rdq will be specifically described. In Z(x, y), the local slope dZx,y / dx in the x-direction at a certain coordinate (x, y) can be expressed as follows using the seven-point formula.

Equation

[0079] At this time, assuming the number of data points in the x-direction and y-direction are X and Y respectively, note that when using the seven-point formula, the values at x = 1, 2, 3, X - 2, X - 1, X cannot be calculated. From these, the root mean square slope Rdq in the measurement area can be obtained from the following formula.

Equation

[0080] When the Rdq of the surface of the tantalum pentoxide substrate after the plasma treatment in Example 1 (fluorine compound unbonded) was measured, Rdq = 0.055. Also, in Example 1, the Rdq of the surface of the substrate of the ink repellent member to which the fluorine compound was bonded was 0.055, which was the same as the surface of the substrate before bonding the fluorine compound. Fig. 4(a) is a diagram showing the state when the surface of the substrate (fluorine compound unbonded) after the plasma treatment in Example 1 was measured by AFM, and Fig. 4(b) is a diagram showing the state when the surface of the substrate of the ink repellent member to which the fluorine compound in Example 1 was bonded was measured by AFM. Fig. 4(c) is a diagram showing the state when the surface of the substrate (fluorine compound unbonded) after the plasma treatment in Comparative Example 2 was measured by AFM, and Fig. 4(d) is a diagram showing the state when the surface of the substrate of the ink repellent member to which the fluorine compound in Comparative Example 2 was bonded was measured by AFM.

[0081] (Evaluation 3: Ratio of fluorine atomic amount before immersion treatment and amount of fluorine compound bonded after immersion treatment) For the substrate surface of the ink repellent member before the following immersion treatment to which the fluorine compound was bonded, the ratio of the fluorine atomic amount (ratio of the fluorine atomic amount to the total of the carbon atomic amount, oxygen atomic amount, fluorine atomic amount, silicon atomic amount, and tantalum atomic amount) was measured by X-ray photoelectron spectroscopy. Also, for the substrate surface of the ink repellent member after the following immersion treatment, F (ratio of the fluorine atomic amount to the total of the carbon atomic amount, oxygen atomic amount, fluorine atomic amount, silicon atomic amount, and tantalum atomic amount) was measured, and the amount of the fluorine compound bonded was evaluated. In Example 1, the ratio of the fluorine atomic amount on the surface side of the ink repellent member before the immersion treatment was 53.5 atm%. Also, in Example 1, the ratio of the fluorine atomic amount (F) on the surface side of the ink repellent member after the following immersion treatment was 53.5 atm%.

[0082] (Immersion treatment) (1) A test piece (thickness: about 700 μm, area: about 2 cm square) including the surface of the substrate of the ink repellent member to which the fluorine compound was bonded was placed in a sealable container containing hydrofluoroether (Novec 7200, boiling point: 76 °C, manufactured by 3M) with a boiling point of 60 °C or higher, and immersed so that the entire test piece was submerged. (2) Maintain at 60 °C for 4 hours in a closed state. XPS measurement conditions Measuring device: QuanteraII (trade name), manufactured by ULVAC-PHI, Inc. X-ray source: AlKα Analysis area: φ200 μm Pass energy: 140 eV Number of integrations: 10 Detection angle: 45° Detected elements: C, O, F, Si, Ta XPS peaks: C1s, O1s, F1s, Si2p, Ta4f

[0083] (Evaluation 4: Evaluation of ink resistance) The ink resistance of the ink-repellent member bonded with the fluorine compound is evaluated by the following procedure. Alkaline dye ink (BCI-7C, manufactured by Canon Inc.) is used as the ink. The ink is put into a PFA container, and the ink-repellent member is immersed so that the entire surface is in contact with the ink, and then covered and sealed. In that state, it is placed in an oven and maintained at a temperature of 60 °C for 30 weeks. After taking out the ink-repellent member and thoroughly washing it with water to remove the ink, the receding contact angle is measured and evaluated by the following method.

[0084] A contact angle meter (product name: DM-701, manufactured by Kyowa Interface Science Co., Ltd., analysis software: FAMAS (ver. 3.5.5)) is used. The measurement conditions are as follows. · Droplet: 2 μL (pure water) · Receding contact angle: Calculated by the droplet method.

[0085] The measurement of the receding contact angle was specifically carried out by the following method. The contact angle at 80 points was measured at 15-second intervals after droplet deposition. Using the values of the contact angle and contact radius (unit: μm) at a certain time calculated from the above software, the following calculations were performed in order from time 0 seconds, and the following processes (A) and (B) were carried out. (A) The value R of the contact radius at time t t , and the value R of the contact radius 90 seconds after t t+90 When taking them, (R t -R t+90 ) 2 The value x of was calculated. When the value of x is 200 or less, the process of (A) was performed again, and the contact angle at the time t when the value of x first exceeded 200 was defined as the receding contact angle.

[0086] A: The receding contact angle is 100° or more B: The receding contact angle is 95° or more and less than 100° C: The receding contact angle is 90° or more and less than 95° D: The receding contact angle is 85° or more and less than 90° E: The receding contact angle is less than 85°

[0087] (Evaluation 5: Evaluation of sliding resistance) The sliding resistance of the ink-repellent member to which the fluorine compound is bonded is evaluated by the following procedure. A high-density felt material (CS-7, manufactured by Taber Industries) is attached to a friction and wear tester (FPR-2100, manufactured by Reska Corporation) as a sliding material, and a reciprocating sliding test is performed on the surface of the ink-repellent member. The sliding load is 650 g, the sliding width is 10 mm, the linear velocity is 50.8 mm / sec, and the number of sliding times is 15,000 times. For the surface of the ink-repellent member after sliding, the receding contact angle was measured and evaluated by the method described in Evaluation 4.

[0088] The specifications of the base films and ink-repellent members according to Examples 1 to 5 and Comparative Examples 1 to 3, as well as the evaluation results of Evaluation 1, Evaluation 2, and Evaluation 3, are summarized in Table 1 below. The static contact angle of the fluorine-unbonded base surface after plasma treatment was measured under the same conditions (liquid droplet) using the same equipment as that used in Evaluation 4, and the contact angle 1 second after droplet deposition was defined as the static contact angle. [Table 1]

[0089] The results of Evaluation 4 and Evaluation 5 of the ink-repellent films according to Examples 1 to 5 and Comparative Examples 1 to 3 are summarized in Table 2 below. [Table 2]

[0090] To satisfy practicality as a repellent ink member, the contact angle needs to be 90° or more. Therefore, it can be said that the repellent ink members according to Examples 1 to 5, which are A to C for both ink resistance and sliding resistance, have superior practical characteristics compared to the repellent ink members according to Comparative Examples 1 to 3.

[0091] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) A repellent ink member having a base containing an oxide of tantalum, with a fluorine compound bonded to the surface of the base via a Ta-O-Si bond, when the surface after performing the following immersion treatments (1) and (2) on the repellent ink member is measured by X-ray photoelectron spectroscopy, and the ratio of the fluorine atomic weight to the total of the carbon atomic weight, oxygen atomic weight, fluorine atomic weight, silicon atomic weight, and tantalum atomic weight is defined as F, the repellent ink member is characterized in that F is 50 atm% or more. (Immersion treatment) (1) Cut out a test piece including the surface from the repellent ink member, put it in a sealable container containing a fluorine solvent containing hydrofluoroether with a boiling point of 60°C or higher, and immerse it so that the entire test piece is submerged. (2) After the immersion in (1), maintain it at 60°C for 4 hours in a sealed state. (Configuration 2) A repellent ink member having a base containing an oxide of tantalum, with a fluorine compound bonded to the surface of the base via a Ta-O-Si bond, the repellent ink member is characterized in that the root mean square slope (Rdq) on the surface is 0.08 or less. (Configuration 3) The repellent ink member according to Configuration 1, characterized in that the root mean square slope (Rdq) on the surface is 0.08 or less. (Configuration 4) The repellent ink member according to any one of Configurations 1 to 3, characterized in that the fluorine compound has a main chain having a perfluoropolyether structure and a perfluoromethyl group at the terminal. (Configuration 5) The ink repellent member according to any one of Configurations 1 to 4, characterized in that the fluorine compound has at least one of the structures represented by the following formula (2), the structure represented by the following formula (3), the structure represented by the following formula (4), and the structure represented by the following formula (5).

Chem.

Chem.

Chem.

Chem.

Explanation of Reference Numerals

[0092] 1 ··· First flow path substrate / 2 ··· Second flow path substrate / 3 ··· Adhesive layer / 4 ··· Nozzle / 5 ··· Energy generating element for ejection / 6 ··· Orifice plate / 6a ··· Orifice surface / 7 ··· Electrode / 8 ··· First through-flow path / 9 ··· Second through-flow path / 10 ··· Liquid flow path / 19 ··· Third through-flow path / 21 ··· Non-ink adhesion member / 22 ··· Substrate / 23 ··· Surface / 100 ··· Inkjet head

Claims

1. An ink repellent member having a base layer containing a tantalum oxide, wherein a fluorine compound is bonded to the surface of the base layer via a Ta—O—Si bond, wherein, when the surface after performing the following immersion treatments (1) and (2) on the ink repellent member is measured by X-ray photoelectron spectroscopy, and the ratio of the fluorine atomic weight to the total of the carbon atomic weight, oxygen atomic weight, fluorine atomic weight, silicon atomic weight, and tantalum atomic weight is defined as F, F is 50 atm% or more. (Immersion treatment) (1) A test piece including the surface is cut out from the ink repellent member and placed in a sealable container containing a fluorine solvent containing hydrofluoroether having a boiling point of 60° C. or higher, and immersed so that the entire test piece is submerged. (2) After the immersion in (1), it is maintained at 60° C. for 4 hours in a sealed state.

2. An ink repellent member having a base layer containing a tantalum oxide, wherein a fluorine compound is bonded to the surface of the base layer via a Ta—O—Si bond, wherein the root mean square slope (Rdq) on the surface is 0.08 or less.

3. The ink repellent member according to claim 1, wherein the root mean square slope (Rdq) on the surface is 0.08 or less.

4. The ink repellent member according to claim 1 or 2, wherein the fluorine compound has a main chain having a perfluoropolyether structure and a perfluoromethyl group at a terminal.

5. The ink repellent member according to claim 1 or 2, wherein the fluorine compound has at least one of the structures represented by the following formula (2), the structure represented by the following formula (3), the structure represented by the following formula (4), and the structure represented by the following formula (5). 【Chemical 1】 [Chemical Formula 2] [Chemical Formula 3] 【Chemical Formula 4】 (In formula (2), formula (3), formula (4), and formula (5), n1, n2, n3, and n4 each independently represent an integer of 1 or more.)

6. The ink repellent member according to claim 1 or 2, wherein the number average molecular weight of the fluorine compound is 4,000 or more.

7. The ink repellent member according to claim 1 or 2, having a substrate, wherein the base layer is provided on the substrate.

8. A method for manufacturing an ink repellent member having a base layer containing a tantalum oxide, wherein a fluorine compound is bonded to the surface of the base layer via a Ta—O—Si bond, the method comprising the following steps (1) and (2). Step of subjecting the surface of the substrate to plasma treatment in an atmosphere with an oxygen concentration of 50% by volume or more 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 substrate 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. Each R independently represents a hydrogen atom or an alkyl group. * indicates the bonding position in the fluorine compound.)

9. The method for manufacturing a ink repellent member according to claim 8, wherein in the step (2), the applied fluorine compound is heated to 100°C or higher to effect dehydration and condensation

10. The method for manufacturing a ink repellent member according to claim 8 or 9, wherein in the step (1), the oxygen concentration is 75% by volume or more

11. An inkjet head comprising the ink repellent member according to claim 1 or 2

12. A method for manufacturing an article, comprising a step of ejecting a liquid using the inkjet head according to claim 11, wherein the liquid is an ink containing a functional material for forming a functional thin film or a functional element

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