Liquid ejecting head

Abstract

A liquid ejecting head includes: an ejecting port for ejecting a liquid; a pressure chamber in which pressure acts on the liquid ejected from the ejection port; a flow path communicating with the pressure chamber; a substrate forming a flow path; and an organic film constituting a part of a wall surface of the flow path and suppressing vibration of the liquid in the flow path, in which the organic film is adhered to the substrate with an adhesive, and the organic film and the adhesive are bonded by a siloxane bond.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head. Background Art

[0002] Microstructured flow path components are used in, for example, the liquid ejecting heads of inkjet recording devices. Inkjet recording devices are recording devices that eject ink from the nozzles of the liquid ejecting head, thereby forming characters and images on a medium. For example, in a piezoelectric inkjet recording device, a piezoelectric element is mounted facing a pressure chamber that communicates with the nozzle that ejects the liquid, with a vibrating plate interposed between the piezoelectric element and the pressure chamber.

[0003] Applying voltage to the piezoelectric element displaces the piezoelectric element and the vibrating plate, changing the volume of the pressure chamber and causing liquid to be ejected from the nozzle. The vibration of the vibrating plate is transmitted to adjacent nozzles through the liquid in the liquid flow path. This is called crosstalk and can cause poor ejection of liquid from adjacent nozzles. Summary of the Invention

[0004] Therefore, a device for providing a vibration damper in the flow path component to face the piezoelectric element is used. The vibration damper needs to have ink tolerance, heat resistance that can withstand the adhesive curing temperature, and an elastic modulus and film thickness suitable for acting as a vibration damper film. Materials that meet these characteristics can be, for example, polyimide, LCP, etc., but these materials are generally difficult to adhere with adhesives. In addition, since the vibration damper is set in the flow path component adhered to the recording element substrate, it is necessary to use an adhesive to adhere the vibration damper in the pre-process. However, there are problems with the adhesion reliability between the adhesive and the vibration damper film.

[0005] WO 2020 / 045112 discloses the use of a film comprising a heat-resistant resin (e.g., polyimide) and a resin composition (e.g., benzocyclobutene (BCB)), and proposes a technology in which the film comprising the heat-resistant resin is surface-treated, such as plasma-treated, to produce ester bonds with the resin composition and improve adhesion.

[0006] However, when the inventors of the present invention studied the adhesion of the components having ester bonds described in WO 2020 / 045112, they confirmed that the bond between the organic film, which acts as a damper film, and the adhesive deteriorated over time when the organic film was immersed in ink. Therefore, in inkjet recording devices that are in constant contact with ink, the adhesion is insufficient to use the technology of WO 2020 / 045112, and there is a risk that the organic film and adhesive will peel off in a short period of time. The present disclosure relates to a liquid ejection head in which the initial adhesive strength of an adhesive to an organic film is high and the adhesive strength is less likely to decrease even when the organic film is immersed in ink.

[0007] The present disclosure relates to a liquid ejecting head comprising: a spray port for spraying liquid; a pressure chamber in which pressure acts on the liquid ejected from the ejection port; a flow path communicating with the pressure chamber; a substrate forming a flow path; and an organic film constituting a portion of a wall surface of the flow path and suppressing vibration of the liquid in the flow path, wherein adhering the organic film to the substrate with an adhesive, and The organic film and the adhesive are bonded via a siloxane bond.

[0008] According to the present disclosure, it is possible to provide a liquid ejection head in which the initial adhesive strength of the adhesive to the organic film is high and the adhesive strength is less likely to decrease even when the organic film is immersed in ink. Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic cross-sectional view of a liquid ejecting head; Figure 2 is a schematic diagram illustrating a chip shear measurement; and Figures 3A to 3I An example of an organic film forming process is shown. DETAILED DESCRIPTION

[0010] In the present disclosure, the expression "from XX to YY" or "XX to YY" when referring to a numerical range means that the numerical range includes the lower limit and the upper limit as endpoints, unless otherwise specified. In addition, when describing a numerical range in a step-by-step manner, the upper and lower limits of each numerical range can be arbitrarily combined. In addition, in the present disclosure, for example, a description such as "at least one selected from XX, YY, and ZZ" means any of the following: XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, and a combination of XX, YY, and ZZ.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The following embodiments do not limit the present disclosure, and not all feature combinations described in the present embodiments are required for the present disclosure. The same constituent elements may be given the same reference numerals.

[0012] Liquid ejection head Figure 11 is a schematic cross-sectional view of a liquid ejection head equipped with a flow path member 10 according to a first embodiment. The liquid ejection head 1 is manufactured by joining the flow path member 10 and a nozzle plate 2 equipped with ejection ports 3 for ejecting liquid. The liquid ejection head 1 is suitable for use as an inkjet recording head mounted on a recording device that ejects ink to form characters and images on a medium.

[0013] The flow path member 10 is formed by joining a first substrate 11 having a recess 12 and a first flow path 13 to a second substrate 21 forming a second flow path 23, which communicates with an organic film 25. Thus, the liquid ejecting head is equipped with a substrate forming the flow path 13. The first substrate 11 is shaped so that the organic film 25, which acts as a damper film to suppress liquid vibrations, covers the recess 12. In addition to the second flow path 23, the second substrate 21 also has an ejection element 4 that generates pressure to eject liquid from the ejection port 3, and a pressure chamber 6 in which the pressure generated by the ejection element 4 acts on the liquid.

[0014] The first substrate 11 and the second substrate 21 are bonded to form the flow path member 10, and the liquid flowing through the first flow path 13 is supplied to the pressure chamber 6 via the second flow path 23. The pressure generated by the ejection element 4 acts on the liquid supplied to the pressure chamber 6, causing the liquid to be ejected from the ejection port 3.

[0015] The ejection element 4 may be a piezoelectric element that is displaced by application of voltage, or a thermoelectric transducer that generates heat by application of voltage. When the ejection element 4 is a piezoelectric element, it is preferable to have a vibration plate 5 between the piezoelectric element and the pressure chamber 6. By having the vibration plate 5, the displacement of the piezoelectric element is easily transmitted to the liquid in the pressure chamber 6. In an inkjet recording head equipped with a piezoelectric element, as described above, vibration is transmitted to adjacent ejection ports through the liquid in the flow path (so-called crosstalk), which may cause poor ejection of liquid from the adjacent ejection ports.

[0016] The flow path component 10 includes an organic film 25 that can act as a vibration damper membrane. When vibrations from the ejection element 4 or the vibrating plate 5 are transmitted to the organic film 25 via the liquid in the second flow path 23, the organic film 25 acts as a vibration damper and dampens the vibrations of the liquid. Therefore, the organic film 25 can suppress crosstalk. In other words, the liquid ejection head according to the present disclosure is suitable for situations where the ejection element, which is susceptible to crosstalk, is a piezoelectric element. Furthermore, the recess 12 is provided with an air communication hole 35 for communicating with the atmosphere.

[0017] Thus, for example, the liquid ejection head 1 includes an ejection port 3 for ejecting liquid, a pressure chamber 6 in which pressure acts on the liquid to be ejected from the ejection port 3, and a flow path 13 communicating with the pressure chamber 6. The liquid ejection head 1 also includes an organic film 25 that constitutes a portion of the wall surface of the flow path 13 and suppresses vibration of the liquid in the flow path 13. The liquid ejection head 1 also includes an ejection element 4 that generates pressure, and the ejection element 4 is preferably a piezoelectric element.

[0018] The organic film 25 is adhered to the substrate using an adhesive. Figure 1 In the embodiment, the first substrate 11 and the second substrate 21 are bonded to each other with the organic film 25 interposed therebetween. In this case, for example, the following (A) and / or (B) are satisfied. (A) The first substrate 11 and the organic film 25 are adhered to each other using an adhesive. (B) The second substrate 21 and the organic film 25 are adhered to each other using an adhesive. This embodiment is not limitative as long as the organic film is adhered to the substrate using an adhesive.

[0019] Organic film and adhesive are bonded by siloxane bond.The inventor has found that, by siloxane bond, organic film and adhesive are bonded, adhesive has a high initial bonding strength to organic film, and even when the film is immersed in ink material, bonding strength is unlikely to reduce. This is considered to be because the water repellency and oil repellency of siloxane bond are higher than the water repellency and oil repellency of other bonds (such as ester bond), so the durability of ink material is improved. Therefore, ink material is not particularly limited, can apply water-based ink material and organic ink material. The example of organic ink material is acrylic ink material.

[0020] organic film The organic film 25 needs to have ink resistance and heat resistance equal to or higher than the thermal curing temperature of the adhesive. As the organic film 25, the following can be mentioned as candidates: super engineering plastics such as polyimide, epoxy resin, liquid crystal polymer resin (LCP), polyetheretherketone (PEEK) and polyetherimide (PEI). In addition, from the perspective of ink resistance, polyamide is difficult to use with ink types containing acrylic monomers, but can be used with water-based inks (such as latex inks). The organic film 25 preferably includes at least one selected from polyimide and epoxy resin. The organic film 25 more preferably includes polyimide.

[0021] It is more preferred to generate functional groups on the surface of the organic film because the reactivity with the silane reagent described below is increased, and the bonding performance between the organic film and the silane reagent is enhanced. Methods for increasing the number of functional groups on the surface of the organic film include plasma treatment and chemical treatment, as shown in WO 2020 / 045112. Preferably, the portion of the organic film in contact with the adhesive is plasma treated. In addition to generating functional groups on the film surface to form a silane reagent layer, an organic film can also be used in which a silane reagent is added to the resin in advance so that the silane reagent that has reacted with the functional groups in the resin is present on the film surface after the solvent evaporates or after curing.

[0022] Furthermore, when the organic film is used as a damper film, in order to exhibit damper performance, the elastic modulus of the organic film is preferably 15 GPa or less, more preferably 10 GPa or less. Although there is no specific lower limit, the elastic modulus of the organic film is preferably 3 GPa or more, more preferably 4 GPa or more. From the viewpoint of exerting vibration damping performance, the thickness of the organic film is preferably 10 μm or less, more preferably 7 μm or less. Although there is no specific lower limit, the thickness of the organic film is preferably 1 μm or more, more preferably 1.5 μm or more.

[0023] As a result of intensive research by the present inventors, it has been found that polyimide is particularly preferably used for the organic film from the viewpoint of high ink resistance to a variety of inks, elastic modulus, and film-forming properties enabling the formation of a desired film thickness. Examples of monomers that can be used to prepare polyimide include diamines, triamines, carboxylic dianhydrides, and carboxylic trianhydrides.

[0024] Examples of the diamines include phenylenediamine and its derivatives, diaminobiphenyl compounds and its derivatives, diaminodiphenyl compounds and its derivatives, diaminotriphenyl compounds and its derivatives, diaminonaphthalene and its derivatives, aminophenylaminoindanes and its derivatives, diaminotetraphenyl compounds and their derivatives, diaminohexaphenyl compounds and their derivatives, and cardo-type fluorenediamine derivatives.

[0025] Specifically, examples of diamines include 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, Alkane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, diaminodiphenyl ether, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide , 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminobenzophenone) hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diamino-3,3'-dimethyldiphenylmethane, and 4,4'-diaminodiphenyl sulfoxide.

[0026] Other examples of diamines include 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, and 1,3-bis(4-aminophenoxy)benzene, 3,3'-bis(3-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, 9,9-bis(4-aminophenyl)fluorene, bis[4-(3 1-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane. These diamines may be used alone or in combination of two or more.

[0027] Examples of the carboxylic anhydride include pyromellitic dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2,6,6-biphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 3,3',4,4'-dicarboxyphenyl Benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, oxydiphthalic anhydride, 4,4-(p-phenylenedioxy)diphthalic dianhydride, 4,4-(isophenylenedioxy)diphthalic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-diphthalic anhydride fluorene, 3,3',4,4'-diphenylsulfoxidetetracarboxylic dianhydride, and the like. Examples of aliphatic tetracarboxylic dianhydrides include ethylene tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1,2,3,4-cyclohexane tetracarboxylic dianhydride, etc. These may be used alone or in combination of two or more.

[0028] The polyimide is preferably an imide of a polyamic acid made of a diamine and a carboxylic anhydride. The polyamic acid may be commercially available, for example, polyamic acid solution PI2610 (product name: manufactured by HD Microsystems, Inc.).

[0029] The epoxy resin is not particularly limited, and known epoxy resins can be used. The epoxy resin is preferably a photosensitive epoxy resin, and is preferably a cured product of an epoxy resin composition comprising a difunctional or higher functional epoxy resin and a photoacid generator. As the difunctional or higher functional epoxy resin, EPICLON N695 (DIC Corporation), jER 1009F (Mitsubishi Chemical Corporation), etc. can be used.

[0030] Silane reagent A silane agent can be used between the organic film and the adhesive. Silane agents include, for example, silane coupling agents. The silane agent is not particularly limited, but those having a functional group that reacts with the organic film are more preferred because a chemical bond is formed between the organic film and the silane agent, thereby increasing the adhesive force. It is therefore preferred that the adhesion between the organic film and the adhesive comprises a bond via a silane reagent.

[0031] More specifically, it is preferable that the liquid ejection head further contains a bond represented by the following formula (1) in addition to the siloxane bond between the organic film and the binder. -C1-X-C2-(1) In formula (1), X is at least one selected from -CO-NH-, -CH2-CHOH-CH2-O-CO-CH2-CH2-, -CHOH-CH2-N-, -CH2-(CH2-O-CH2)n-CH2-, -CO-O-, -CO-S-, -O-, and -NH-CO-O-, n is the average molar number of addition and represents an integer from 1 to 200 (preferably 10 to 200), and C1 and C2 are each independently a carbon atom. More preferably, X is at least one selected from -CO-NH-, -CH2-CHOH-CH2-O-CO-CH2-CH2-, -CHOH-CH2-N-, and -CH2-(CH2-O-CH2)n-CH2-. The method for confirming the bond between the organic film and the binder is not particularly limited, and known means can be used. Examples include etching the organic surface with an argon cluster ion beam and time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0032] For example, when a polyimide film is used as an organic film, it is known that carboxylic acid is generated on the polyimide surface after plasma treatment. Therefore, when the silane reagent has an amino group, an epoxy group, or a hydroxyl group, chemical bonds such as an amide bond, an epoxy ester bond, and an ester bond are generated between the silane reagent and the polyimide, respectively. Therefore, silane reagents having these functional groups are suitable examples. For example, a silane reagent may be applied to a portion of the organic film to be adhered to the adhesive, and heated to bond the organic film and the silane reagent.

[0033] The organic film may further contain a silane reagent. For example, in the case where the silane reagent is pre-added to the resin to be used for the organic film, a silane reagent having a functional group capable of reacting with a functional group in the resin may be used. The leaving group of the silanol group is not particularly limited and may be any group that is hydrolyzed by water, such as a methoxy group or an ethoxy group.

[0034] Taking these factors into consideration, the silane agent may be, for example, at least one silane coupling agent selected from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, Silane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)-propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, etc.

[0035] The silane agent preferably includes at least one selected from an aminosilane agent and an epoxysilane agent, and more preferably includes an aminosilane agent. The aminosilane agent makes it easier to maintain adhesion when immersed in an organic ink.

[0036] The aminosilane agent is preferably at least one selected from the group consisting of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)-propylamine, N-phenyl-3-aminopropyltrimethoxysilane and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride. A commercially available aminosilane reagent such as VM-652 (manufactured by HD Microsystems, Inc.) can be used.

[0037] The epoxysilane reagent may be, for example, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltriethoxysilane. Commercially available epoxy silane reagents such as AP3000 (DuPont), KBM-402 (Shin-Etsu Chemical Co., Ltd.), and KBE-403 (Shin-Etsu Chemical Co., Ltd.) can be used.

[0038] Adhesives The adhesive can be any adhesive capable of bonding the organic film and the adhesive via a siloxane bond. There is no particular restriction on the bonding method. When the surface of the organic film is treated with a silane reagent, an adhesive that forms a siloxane bond with the silane reagent can be used. Alternatively, an adhesive having a siloxane bond in its structure can be used to bond the adhesive to the organic film, thereby bonding the organic film and the adhesive via a siloxane bond. Alternatively, functional groups can be formed on the surface of the organic film, and an adhesive having a siloxane bond can be bonded to the functional groups. The organic film and the adhesive can be bonded via a silane reagent that is capable of bonding the organic film and the adhesive and has a siloxane bond.

[0039] From the viewpoint of water repellency, an adhesive having a lower oxygen atomic percentage is preferred. Examples of adhesives include at least one selected from silsesquioxane derivatives, divinylsiloxane bisbenzocyclobutene, dimethylpolysiloxane, tetramethylcyclotetrasiloxane, and the like. These may be used alone or in combination of two or more.

[0040] Adhesive preferably comprises the resin containing cyclobutene skeleton. More preferably, adhesive comprises divinylsiloxane-bisbenzocyclobutene.When using divinylsiloxane-bisbenzocyclobutene, after the organic film processed with silane reagent and substrate adhere to each other by adhesive, the silane reagent and adhesive can react to form the key comprising siloxane bond.For example, the reaction between silane reagent and adhesive can be promoted by heating.In addition, YL9028 (Mitsubishi Chemical Corporation) is also preferably used as the adhesive with siloxane bond Si-O-Si in structure.

[0041] substrate The substrate is not particularly limited as long as it has adhesion reliability. Suitable examples include silicon wafers and substrates having a film formed on the silicon wafer of at least one selected from SiC, SiN and SiO. The above-mentioned organic films can also be used as adherends.

[0042] Method for manufacturing liquid ejecting head An example of a method for producing a liquid ejecting head will be described. The following description will focus on an example of forming a flow path member and an organic film. In the following example of a method for producing a liquid ejecting head, the substrate to which the organic film is attached with an adhesive is the second substrate 21. First, prepare the first substrate 11. Then, Figure 3A As shown, a recess 12 and a first flow path 13 through which a fluid will flow are formed in a first substrate 11. The recess 12 and the like can be formed by any known means, such as deep silicon dry etching. The surface of the first substrate 11 may be treated with a silane coupling agent. This can improve the adhesion between the first substrate and the organic film.

[0043] Next, an organic film is formed on the prepared first substrate 11. For example, an attachment member on which a polyamic acid film has been formed may be obtained, and the polyamic acid film may be transferred to the first substrate and heated to form a polyimide film, which is an organic film. Figure 3B As shown, a solution containing polyamic acid is applied to a PET film, which is an attachment member 14. Then, the substrate is heated at 120 to 250°C, preferably 130 to 200°C, for 5 to 30 minutes, to form a polyamic acid film 15.

[0044] Next, if Figure 3C As shown, the polyamic acid film 15 is transferred and attached to the first substrate 11 to cover the recess 12 and the first flow path 13. Then, as shown in FIG. Figure 3D As shown, while being supported by a support member 16, the polyamic acid film 15 attached to the first substrate 11 is baked for imidization. For example, a silicon substrate can be used as the support member 16. There is no particular limitation on the baking method for imidization. The temperature is preferably 300 to 400°C, more preferably 320 to 380°C. The time is, for example, 10 to 300 minutes, preferably 30 to 200 minutes. The polyamic acid film 15 reacts to form a polyimide film 25 through the heat treatment.

[0045] Next, if Figure 3E As shown, the support member 16 is removed. For example, it can be removed by etching after grinding and thinning. As a result, a flow path member having a polyimide film 25 is formed, which is arranged as a damper film to cover the recess 12 and the first flow path 13.

[0046] Next, the surface of the organic film to be attached to the adhesive is treated with plasma. Figure 3E The outer surface of the polyimide film 25 in the adhesive is treated with plasma. Specifically, the portion in contact with the adhesive is treated with plasma. This allows functional groups to be generated on the surface of the organic film, making it more susceptible to reaction with the silane reagent. As the plasma treatment, for example, hydrophilic treatment by oxygen plasma irradiation using active oxygen can be used.

[0047] Then, the surface of the organic film treated with plasma is treated with a silane reagent. This process allows a bond to be formed between the silane reagent and the organic film. For example, a silane reagent layer is formed on the surface of the organic film that has been treated with plasma. Figure 3F As shown, a silane reagent is applied to the polyimide film 25 by a known application method (such as spin coating) to form a silane reagent layer 26. In addition, heating may be performed at, for example, 70 to 120° C. for 30 to 300 seconds. This can promote the reaction between the functional groups on the surface of the polyimide film 25 and the silane reagent.

[0048] Next, a flow path is formed in the organic film. If necessary, a photoresist layer can be provided to protect the area outside the flow path. Figure 3G As shown, in order to prevent the polyimide film 25 and the silane reagent layer 26 formed on the area other than the first flow path 13 from being removed, a positive photoresist 33 serving as an etching mask is formed on the silane reagent layer 26. Then, as shown in FIG. Figure 3H As shown in FIG. 1 , the photoresist 33 formed on the first flow path 13 is removed by photolithography. Figure 3I As shown, the polyimide film 25 and the silane reagent layer 26 on the first flow path 13 are removed by chemical dry etching, so that the flow path is connected to the organic film.

[0049] Next, in order to form Figure 1 The second flow path 23 in the first substrate 11 is formed to bond the second substrate 21 to the second substrate 21. Specifically, the second substrate 21 and the organic film on the first substrate 11 are bonded together using an adhesive. Specifically, the organic film is bonded to the second substrate 21 using an adhesive, and the organic film and the adhesive are bonded via siloxane bonds. The method for forming the bond via siloxane bonds is described above.

[0050] The above is an example of a method for manufacturing a liquid ejecting head. The method for manufacturing a liquid ejecting head preferably includes: a step of plasma-treating the surface of the organic film to be adhered to the adhesive; a step of treating the plasma-treated surface of the organic film with a silane reagent; and a step of adhering the organic film and the substrate with the adhesive, thereby bonding the organic film and the adhesive via a siloxane bond. Example

[0051] The present disclosure will be described in more detail below with reference to Examples and Comparative Examples, but the present disclosure is not limited thereto.

[0052] Example of manufacturing a liquid ejecting head An example of forming a flow path member and an organic film in connection with the manufacture of a liquid ejecting head will be described below. Figures 3A to 3I : is a cross-sectional view showing a method for manufacturing the flow path component of the first embodiment. Figure 3A As shown, a first substrate 11 for forming the recess 12 and the first flow path 13 through which the fluid will flow is prepared. For the first substrate 11, single crystal silicon having a size of 200 mmφ and a thickness of 500 μm is used.

[0053] In order to improve the adhesion between the first substrate 11 and the polyamic acid film 15 described below, a silane coupling agent VM-652 (manufactured by HD Microsystems, Inc.) was applied to the surface of the first substrate 11 under the conditions of 2000 rpm and 30 seconds. Then, a silane agent layer was formed on the surface of the first substrate 11 by heating at 90° C. for 90 seconds on a hot plate. Then, silicon deep dry etching was used to form the recess 12 and the first flow path 13 ( Figure 3A ).

[0054] Next, if Figure 3B As shown, a polyamic acid solution PI2610 (HD Microsystems, Inc.) was applied to a 100 μm thick PET film, which was the attachment member 14, by spin coating (conditions: 2500 rpm, 30 seconds). Then, by baking in a clean oven at a temperature of 150° C. for 15 minutes, a polyamic acid film 15 with a thickness of 5 μm was formed.

[0055] Next, if Figure 3C As shown, a polyamic acid film 15 is attached to the first substrate 11 to cover the recess 12 and the first flow path 13. The polyamic acid film 15 is attached using a roller method that can apply pressure and heat. Next, the attachment member 14 is peeled off from the attached polyamic acid film 15 while being bent.

[0056] Next, if Figure 3D As shown in FIG. 1 , the polyamic acid film 15 attached to the first substrate 11 is baked for imidization while being supported by the support member 16. A silicon substrate is used as the support member 16. Baking is performed at 350° C. for 1 hour in a nitrogen atmosphere for imidization. The polyamic acid film 15 is reacted into a polyimide film 25 by heat treatment.

[0057] Next, if Figure 3E As shown, the support member 16 is thinned by grinding and then removed by etching. This results in the formation of a flow path member having a polyimide film 25 as a damper film, which is arranged to cover the recess 12 and the first flow path 13.

[0058] Next, the outer surface of the polyimide film 25 was subjected to plasma treatment using a plasma apparatus MAS8220AT (manufactured by Canon Inc.) under the following conditions. (Conditions) 16℃, 0W, 90 seconds

[0059] Then, if Figure 3F As shown, a silane reagent VM-652 (manufactured by HD Microsystems, Inc.) was applied to the polyimide film 25 by spin coating at 2000 rpm for 30 seconds to form a silane reagent layer 26. The reaction between the functional groups on the surface of the polyimide film 25 and the silane reagent was promoted by heating on a hot plate at 90° C. for 90 seconds.

[0060] Next, if Figure 3GAs shown, a positive photoresist 33 is formed on the silane reagent layer 26 as an etching mask to prevent the polyimide film 25 and the silane reagent layer 26 formed on the area other than the first flow path 13 from being removed.

[0061] Then, if Figure 3H As shown, the photoresist 33 formed on the first flow path 13 is removed by photolithography.

[0062] Next, if Figure 3I As shown, the polyimide film 25 and the silane reagent layer 26 on the first flow path 13 are removed by chemical dry etching. A mixture of O2 gas and CF4 gas is used as the etching gas. After the dry etching, the etching mask is removed by oxygen ashing.

[0063] Finally, divinylsiloxane-bisbenzocyclobutene (CYCLOTENE 3022-47, manufactured by Dow Chemical Company, hereinafter referred to as BCB adhesive) was used as an adhesive to form the second flow path 23 ( Figure 1 ) is bonded to the first substrate 11.

[0064] Example 1 2. Preparation of Evaluation Samples As an evaluation sample for evaluating adhesion, a bonded body in which a substrate, an adhesive, and an organic film were adhered was prepared. Adhesion was evaluated by evaluating the die shear between the organic film and the adhesive before and after immersion in the ink ( Figure 2 ).

[0065] 2-1. Preparation of organic films for evaluation samples Through the above Figures 3A to 3I The support on which the organic film used in this study was formed was prepared by the steps in . First, a support made of single crystal silicon was prepared. Furthermore, a silane coupling agent, VM-652 (manufactured by HD Microsystems, Inc.), was applied to the polyamic acid film-attached surface of the support at 2000 rpm for 30 seconds. This improved adhesion between the support and the polyamic acid film. The silane coupling agent was baked by heating on a hot plate at 90°C for 90 seconds.

[0066] Next, a polyamic acid solution PI2610 (HD Microsystems, Inc.) was applied on the silane coupling agent by spin coating (conditions: 2500 rpm, 30 seconds) to form a polyamic acid film. Next, the substrate was baked in a clean oven at 150° C. for 15 minutes. Polyamide acid is a precursor of polyimide and can be obtained, for example, by reacting aromatic diamine with tetracarboxylic dianhydride in an organic solvent such as N-methylpyrrolidone.

[0067] Then, the polyamic acid film attached to the substrate was reacted into a polyimide film by heating at 340° C. for 2 hours using a clean oven. Finally, the polyimide film on the substrate (which had the polyimide film as the outermost surface) was subjected to plasma treatment using a plasma apparatus MAS8220AT (manufactured by Canon Inc.) under the following conditions to obtain an organic film-coated support. (Conditions) 16℃, 0W, 90 seconds

[0068] 2-2. Silane reagent coating A silane reagent VM-652 (manufactured by HD Microsystems, Inc.) was applied to the organic film-coated support prepared as described in 2-1 by spin coating at 2000 rpm for 30 seconds. Then, the reaction between the silane reagent and the functional groups present in the surface layer of the organic film-coated membrane support was promoted by heating on a hot plate at 90° C. for 90 seconds. Since the bonds formed between the organic film and the silane reagent differed among the examples, the bonds generated in Examples 1 to 16 are summarized in Table 4 below.

[0069] 2-3. Preparation of bonded body At the same time, a BCB adhesive diluted with a solvent was applied to the release film using a spin coater at 2500 rpm for 30 seconds. Thereafter, the release film coated with the BCB adhesive was heated in an oven heated to 100°C.

[0070] Next, a silicon wafer (Si substrate with a SiC film formed thereon) was prepared, the surface layer of which was coated with polyetheramide HIMAL HL-1200CH (manufactured by Showa Denko Materials Co., Ltd.). The HIMAL-coated silicon wafer was used as a substrate to which the organic film was bonded using a BCB adhesive as an adhesive. The silicon wafer was cut and pressed onto the BCB adhesive on a BCB-coated release film on a hot plate heated to 100°C, thereby applying the BCB adhesive to the surface of the silicon wafer (substrate). This is because the BCB adhesive is in a cured state at room temperature, but when heated to 100°C, it becomes fluid and can be applied to the silicon wafer surface. The BCB adhesive on the silicon wafer surface was then allowed to solidify by standing at room temperature for 3 minutes.

[0071] The organic film-coated support, prepared as described in 2-2 and coated with a silane reagent, was heated to 100°C, and the silicon wafer coated with the BCB adhesive was pressed onto it. This caused the BCB adhesive to temporarily fluidize between the silicon wafer (substrate) and the support, filling the gap between the wafer and the support. The BCB adhesive was then cured by standing at room temperature for 1 hour. After curing, the evaluation sample was heated at 250° C. for 1 hour to promote the reaction between the BCB adhesive and the silane reagent, thereby resulting in a bonded body in which the substrate, the adhesive, and the organic film were bonded. This generates silanol groups, which react with the silane reagent to generate covalent bonds, including siloxane bonds, between the silane coupling agent and the BCB adhesive. Since covalent bonds are formed between the organic film and the silane reagent as shown in Table 4, the organic film and the adhesive become bonded through the siloxane bonds.

[0072] 2-4. Evaluation After obtaining the bonded body, use Figure 2 The die shear strength measurement method shown is used to evaluate the adhesion between polyimide and BCB adhesive. First, a support having an organic film coating on a silicon wafer (the silicon wafer is a substrate) is prepared. Figure 2 As shown, a tool 200 is used to press the silicon wafer in the direction of arrow 201. The pressure is gradually increased, and the pressure value during pattern peeling is measured to evaluate adhesion. The pressure value during pattern peeling is called "die shear strength." The higher the value, the greater the adhesion between the polyimide and the BCB adhesive. More specifically, measurement was performed using a bonding tester DAGE 4000 Plus (manufactured by Nordson Advanced Technology Co., Ltd.) under the following conditions. Tool moving speed: 0.5mm / s

[0073] Next, the organic film-coated support with a silicon wafer thereon (the silicon wafer being the substrate) was immersed in a water-based ink and removed again after 30 days. After removal, the adhesion was measured using the same procedure as after the baking was completed.

[0074] The composition of water-based ink is shown in Table 1-1 below.

[0075] Table 1-2 shows the composition of the organic ink, which will be described below. [Table 1-1] Element Content ratio (weight %) water 70 glycerin 30 [Table 1-2] Element Content ratio (weight %) (5-ethyl-1,3-dioxane-5-yl)methylacrylate 50 Propoxylated neopentyl glycol diacrylate 30 2-Propenoic acid 5 Ethyl 4-diethylaminobenzoate 5 Alcohol (type undisclosed) 2.5 Di(trimethylolpropane) tetraacrylate 2.5 Trimethylolpropane triacrylate 2.5 Hexamethylene diacrylate (HDDA) 1 Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide 1

[0076] Example 2 The conditions were the same as in Example 1, except that the ink used in the evaluation was changed to an organic ink.

[0077] Example 3 The conditions were the same as those in Example 1, except that YL9028 (Mitsubishi Chemical Corporation) was used as the adhesive instead of the BCB adhesive. The structural details of YL9028 are not disclosed, but it is disclosed that the structure has a siloxane bond Si-O-Si.

[0078] Example 4 The conditions were the same as in Example 3, except that the ink used in the evaluation was changed to an organic ink.

[0079] Example 5 The conditions were the same as in Example 1, except that epoxy silane reagent AP3000 (DuPont) was used instead of VM652 as the silane reagent.

[0080] Example 6 The conditions were the same as in Example 5, except that the ink used in the evaluation was changed to an organic ink.

[0081] Example 7 The conditions were the same as in Example 5, except that YL9028 (Mitsubishi Chemical Corporation) was used as the binder instead of the BCB binder.

[0082] Example 8 The conditions were the same as in Example 7, except that the ink used in the evaluation was changed to an organic ink.

[0083] Example 9

[0084] The conditions were the same as those in Example 1, except that a photosensitive epoxy resin (composition: Table 2) was used instead of the polyamic acid solution PI2610 used in the organic film. [Table 2]

[0085] Example 10 The conditions were the same as in Example 9, except that the ink used in the evaluation was changed to an organic ink.

[0086] Example 11 The conditions were the same as in Example 9, except that YL9028 (Mitsubishi Chemical Corporation) was used as the binder.

[0087] Example 12 The conditions were the same as in Example 11, except that the ink used in the evaluation was changed to an organic ink.

[0088] Example 13 The conditions were the same as those in Example 9, except that epoxy silane reagent AP3000 was used instead of VM652 as the silane reagent.

[0089] Example 14 The conditions were the same as in Example 13, except that the ink used in the evaluation was changed to an organic ink.

[0090] Example 15 The conditions were the same as in Example 13, except that YL9028 (Mitsubishi Chemical Corporation) was used as the binder.

[0091] Example 16 The conditions were the same as in Example 15, except that the ink used in the evaluation was changed to an organic ink.

[0092] Comparative Example 1 The conditions were the same as in Example 1, except that a polyurethane adhesive KU550 (Konishi Co., Ltd.) was used as the adhesive.

[0093] Comparative Example 2 The conditions were the same as those in Comparative Example 1, except that the ink used in the evaluation was changed to an organic ink.

[0094] Comparative Example 3 The conditions were the same as in Example 1, except that no silane reagent was used.

[0095] Comparative Example 4 The conditions were the same as those in Comparative Example 3, except that the ink used in the evaluation was changed to an organic ink.

[0096] The above levels are summarized in Tables 3-1 to 3-3. [Table 3-1] [Table 3-2] [Table 3-3]

[0097] Evaluation Results The evaluation results are shown below. In this study, the initial die shear strength (initial adhesion) was set to 10 kgf or higher as a prerequisite, since the initial die shear strength was 9.9 kgf when the workpiece was manufactured according to the prior art without any silane agent treatment. Furthermore, adhesion was rated as A, B, C, or D, depending on the degree of decrease in die shear strength from the initial value after immersion in ink. These benchmarks are summarized below. <Initial Adhesion> A: Initial adhesion above 10kgf B: Initial adhesion less than 10kgf <Adhesion after immersion in ink> A: Adhesion after immersion in ink for 30 days is 95% or more of the initial adhesion B: Adhesion after immersion in ink for 30 days is 85% or more and less than 95% of the initial adhesion C: Adhesion after immersion in ink for 30 days is 75% or more and less than 85% of the initial adhesion D: Adhesion after immersion in ink for 30 days is less than 75% of the initial adhesion

[0098] Types of organic membranes First, in the examples, initial adhesion of 10 kgf or more was achieved for both the polyimide and photosensitive epoxy organic films, and the die shear strength remained above 75% of the initial value even after immersion in ink. However, a comparison of Example 2 and Example 10 shows that when using an organic ink, the organic film made of polyimide has a higher ability to maintain ink adhesion than the organic film made of photosensitive epoxy resin. This is believed to be because epoxy groups are more hydrophilic and lipophilic than imide compounds, and therefore have a higher affinity for the solvent in the ink and are more easily swelled.

[0099] Types of silane reagents In the examples, when the silane agent was an aminosilane agent or an epoxysilane agent, initial adhesion of 10 kgf or greater was achieved, and even after immersion in ink, the die shear strength remained at or above 75% of the initial value. Furthermore, comparison with Comparative Examples 3 and 4, which did not use a silane agent, confirmed the effectiveness of the silane agent in improving adhesion. This is believed to be because the silane agent bonds the organic film and the adhesive via siloxane bonds, thereby strengthening the bond between the organic film and the adhesive.

[0100] In the cases of Comparative Examples 3 and 4, even without using a silane reagent, an ester bond is formed between the carboxyl group on the surface of the organic film and the hydroxyl group of the adhesive, but since the siloxane bond formed in the examples has higher water repellency and oil repellency, it is believed that the durability to the ink is higher.

[0101] Bond between organic membrane and silane reagent

[0102] Table 4 shows the bonds formed in the combination of the organic film and the silane reagent used in this example. [Table 4] Example No. Key Name Key part structure 1 to 4 Amide bond R1-CO-NH-R2 5 to 8 Epoxy ester bond <![CDATA[R1-CH2-CHOH-CH2-O-CO-CH2-CH2-R2]]> 9 to 12 Secondary amines <![CDATA[R1-CHOH-CH2-N-R2]]> 13 to 16 No name <![CDATA[R1-CH2-(CH2-O-CH2)-CH2-R2]]>

[0103] The presence of a siloxane bond between the organic film and the adhesive can improve adhesion, but the results in Table 4 show that adhesion is further improved when a bond represented by the following general formula is present between the organic film and the silane reagent. That is, as described above, it is preferred that a bond represented by formula (1) be present between the organic film and the adhesive in addition to the siloxane bond. General formula of the bond between the organic membrane and the silane reagent R1-CO-NH-R2, R1-CH2-CHOH-CH2-O-CO-CH2-CH2-R2, R1-CHOH-CH2-N-R2, R1-CH2-(CH2-O-CH2)n-CH2-R2 R1 and R2 represent bonding sites to the organic film and the silane reagent, for example, carbon atoms at the terminals of the organic film and the silane reagent. Furthermore, n is the average number of moles added, and is an integer, for example, 1 to 200, preferably 10 to 200.

[0104] Adhesive type When using BCB adhesives or YL9028, which have silanol groups, as the adhesive, initial adhesion of over 10 kgf was achieved, regardless of the type of organic film or silane reagent, and the die shear strength remained over 75% of the initial value even after immersion in ink. Meanwhile, when using the polyurethane adhesive KU-550 as the adhesive, adhesion significantly decreased, and even after immersion in ink, the initial die shear strength did not reach 75%. Therefore, it is believed that the formation of siloxane bonds between the adhesive and the organic film, which have strong covalent bonds and water repellency, is a necessary condition for improving adhesion.

[0105] Furthermore, when comparing the BCB adhesive with YL9028, for example, when comparing Examples 2 and 4, it was shown that the BCB adhesive had slightly better adhesion and ink resistance. This is believed to be because the epoxy group is more hydrophilic and lipophilic than the imide compound, and therefore has a high affinity for the solvent in the ink and is more easily swellable.

[0106] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A liquid ejecting head comprising: a spray port for spraying liquid; a pressure chamber in which pressure acts on the liquid ejected from the ejection port; a flow path communicating with the pressure chamber; The substrate forming the flow path; and an organic film constituting a portion of a wall surface of the flow path and suppressing vibration of the liquid in the flow path, wherein adhering the organic film to a substrate with an adhesive, and The organic film and the adhesive are bonded via a siloxane bond.

2. The liquid ejecting head according to claim 1, wherein A silane agent is present between the organic film and the binder, and the liquid ejection head contains a bond represented by the following formula (1) in addition to the siloxane bond between the organic film and the binder: R1-X-R2(1) In formula (1), X is at least one selected from -CO-NH-, -CH2-CHOH-CH2-O-CO-CH2-CH2-, -CHOH-CH2-N-, -CH2-(CH2-O-CH2)n-CH2-, -CO-O-, -CO-S-, -O-, and -NH-CO-O-, n is the average number of moles added and represents an integer from 1 to 200, and R1 and R2 represent bonding sites with the organic film and the silane reagent. 3 . The liquid ejection head according to claim 1 , wherein the organic film comprises polyimide. 4 . The liquid ejection head according to claim 1 , wherein a portion of the organic film in contact with the adhesive is treated with plasma.

5. The liquid ejecting head according to claim 1 or 2, wherein The adhesion between the organic film and the adhesive comprises a bond through a silane reagent, and The silane reagent comprises an aminosilane reagent.

6. The liquid ejection head according to claim 1 or 2, wherein the binder comprises a resin containing a cyclobutene skeleton. 7 . The liquid ejection head according to claim 1 , wherein the binder contains divinylsiloxane-bisbenzocyclobutene.

8. The liquid ejection head according to claim 1 or 2, further comprising an ejection element that generates pressure, the ejection element being a piezoelectric element.

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