Inkjet recording head and method for manufacturing an inkjet recording head

Abstract

To provide an inkjet recording head with high water repellency and durability, and a method for manufacturing the same. [Solution] An inkjet recording head comprising a substrate, an ejection port forming member provided on the substrate, and a water-repellent layer provided on the ejection port forming member, wherein the water-repellent layer is made of a cured product of a photosensitive resin composition, and the photosensitive resin composition is a specific composition.

Description

Technical Field

[0001] The present disclosure relates to an inkjet recording head and a method for manufacturing an inkjet recording head.

Background Art

[0002] In recent years, technical development for further improving the recording characteristics in an inkjet recording system has been continued. In an inkjet recording head, in order to stably eject small droplets, surface treatment for applying a water-repellent layer to the surface of the opening of the ejection port is often performed. Further, the state of the opening surface of the ejection port is periodically maintained by wiping off the ink remaining on the opening surface of the ejection port with a rubber blade or the like. The water-repellent layer needs to be not eroded by a liquid such as ink and continue to adhere to the surface of the opening of the ejection port even when wiped (rubbed) with a blade or the like. Further, from the viewpoints of simplifying the manufacturing process and reducing costs, it is desired to form the ejection port and the water-repellent layer at once.

[0003] As a material for performing a water-repellent and ink-repellent surface treatment that can be applied on an ejection port forming member and has durability, for example, a material disclosed in Patent Document 1 is disclosed. Patent Document 1 discloses a composition containing a fluorine-containing epoxy resin obtained by a polymerization reaction using a (meth)acrylic monomer containing a perfluoropolyether group having 9 or more carbon atoms and an (meth)acrylic monomer containing an epoxy group.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in recent years, the types of inks used have diversified, and it has been found that when highly concentrated inks that tend to adhere are used, or when durability against abrasion is required, the water-repellent layer using the composition described in Patent Document 1 does not always maintain the water-repellent layer on the head surface.

[0006] As a result of diligent research into the above-mentioned problems, the inventors have found that by appropriately controlling the molecular weight and number of functional groups of (meth)acrylate in the composition and increasing the crosslinkability of the (meth)acrylic skeleton, durability can be improved and the problems can be solved.

[0007] According to one embodiment of the present disclosure, an inkjet recording head having high water repellency and durability is provided. Another embodiment of the present disclosure provides a method for manufacturing an inkjet recording head having high water repellency and durability. [Means for solving the problem]

[0008] An inkjet recording head, wherein the inkjet recording head is substrate, A discharge port forming member provided on the substrate, and The discharge port forming member has a water-repellent layer provided on it, The water-repellent layer consists of a cured product (A) of a photosensitive resin composition. The photosensitive resin composition is (a) a (meth)acrylate having a perfluoropolyether group, (b) an epoxy group-containing (meth)acrylate, Polyfunctional (meth)acrylate (c), Thermal radical polymerization initiator (d) and Contains a photocationic polymerization initiator (e), The (meth)acrylate (a) is a (meth)acrylate having three or more functional (meth)acrylic groups, The polyfunctional (meth)acrylate (c) is a (meth)acrylate having 6 or more functional (meth)acrylic groups and a weight-average molecular weight of 5000 or less. An inkjet recording head characterized by the following features. [Effects of the Invention]

[0009] According to one embodiment of the present disclosure, an inkjet recording head having high water repellency and durability is provided. Another embodiment of the present disclosure provides a method for manufacturing an inkjet recording head having high water repellency and durability. [Brief explanation of the drawing]

[0010] [Figure 1] Perspective schematic diagram of an example of an inkjet recording head. [Figure 2] Cross-sectional view showing an example of an inkjet recording head manufacturing method. [Modes for carrying out the invention]

[0011] In this disclosure, descriptions of numerical ranges such as "XX or greater and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be any combination. In this disclosure, for example, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. Note that if XX is a group, multiple values ​​may be selected from XX, and the same applies to YY and ZZ. In this disclosure, "(meth)acrylic" means "acrylic" and / or "methacrylic." Similarly, "(meth)acrylate" means "acrylate" and / or "methacrylate."

[0012] The embodiments of this disclosure will be described in detail below. The inkjet recording head related to this disclosure is An inkjet recording head, wherein the inkjet recording head is substrate, A discharge port forming member provided on the substrate, and a water repellent layer provided on the discharge port forming member, and has the water repellent layer is composed of a cured product (A) of a photosensitive resin composition, the photosensitive resin composition (meth)acrylate (a) having a perfluoropolyether group, (meth)acrylate (b) having an epoxy group, polyfunctional (meth)acrylate (c), a thermal radical polymerization initiator (d) and a photo cationic polymerization initiator (e), and includes the (meth)acrylate (a) is a (meth)acrylate having 3 or more functional (meth)acrylic groups, the polyfunctional (meth)acrylate (c) is a (meth)acrylate having a weight average molecular weight of 5000 or less and having 6 or more functional (meth)acrylic groups is a (meth)acrylate of which is characterized in that.

[0013] [Composition] The photosensitive resin composition will be described. [(Meth)acrylate (a) having a perfluoropolyether group]< (Meth)acrylate (a) can impart water repellent performance to the water repellent layer. (Meth)acrylate (a) is not particularly limited as long as it has a perfluoropolyether group and has 3 or more functional (meth)acrylic groups, but it preferably has a both-end (meth)acrylate structure from the reactivity with other (meth)acrylates described later. Here, "having a both-end (meth)acrylate structure" means that at least two terminal groups are (meth)acrylic groups. Since (meth)acrylate (a) has a perfluoropolyether group, water repellent performance is exhibited. The (meth)acrylate (a) having three or more functional (meth)acrylic groups improves the crosslinking properties when the photosensitive resin composition is cured, resulting in superior durability of the water-repellent layer. There is no particular upper limit, but from the viewpoint of handling, it is usually six-functional or less. (Meth)acrylate(a) preferably has three to six functional (meth)acrylic groups, more preferably has four to six functional (meth)acrylic groups, and even more preferably has four functional (meth)acrylic groups.

[0014] Furthermore, in order to facilitate the design of a structure with a large number of (meth)acrylic groups in a single molecule, (meth)acrylate(a) preferably has a urethane bond, and it is more preferable that the urethane bond exists between the terminal (meth)acrylic group and the urethane bond via an alkyl group.

[0015] The weight-average molecular weight (Mw) of (meth)acrylate (a) is preferably 5000 or less, and more preferably 2500 or less. When the Mw of (meth)acrylate(a) is 5000 or less, the (meth)acrylic equivalent is low, which improves the crosslinking properties of the cured product and provides excellent durability of the water-repellent layer. The lower limit of Mw for (meth)acrylate(a) is not particularly limited, but is preferably 1500 to 5000, more preferably 2000 to 4000, and even more preferably 3000 to 4000.

[0016] Specifically, (meth)acrylate (a) is preferably a compound represented by the following formula (1).

[0017] [ka] (In formula (1), a and b are each an integer between 0 and 2 (preferably 1). c is the average number of repeats of the repeating unit -(CF2CF2O)-, and d is the average number of repeats of the repeating unit -(CF2O)-, and c and d each independently represent a number of 0 or more and satisfy 15 ≤ (c + d) ≤ 25. If both repeating units are present, these repeating units may be block bonds, random bonds, or a combination of block bonds and random bonds. Y each independently represents a group represented by the following formula (Y1) or formula (Y2), and X each independently represents a group with 2 carbon atoms substituted with 1 to 3 fluorine atoms or (Represents three alkylene groups.)

[0018] [ka]

[0019] [ka] (In equations (Y1) and (Y2), R 1 and R 2 Each of these independently represents either a hydrogen atom or a methyl group.

[0020] Examples of compounds represented by formula (1) include commercially available products such as AD-1700 (trade name, manufactured by Solvay Specialty Polymers). (Meth)acrylate (a) may be used alone or in combination of two or more types.

[0021] Furthermore, many (meth)acrylates (b) and polyfunctional (meth)acrylates (c) having epoxy groups, as described later, are insoluble in fluorinated solvents, and therefore are not suitable for polymerization reactions. Organic solvents are often used. If (meth)acrylate(a) is soluble in organic solvents, polymerization can be carried out in the same solvent, and the polymerization reaction proceeds easily. Therefore, it is preferable that (meth)acrylate(a) is soluble in organic solvents. The organic solvent used here is an organic solvent in which (meth)acrylates (b) and (c) are soluble. Specifically, it is at least one selected from the group consisting of solvents containing ketone groups (ketone solvents), solvents containing ester groups (ester solvents), and solvents containing alcohol groups (alcohol solvents), and more specifically, methyl isobutyl ketone (MIBK). A compound is considered soluble if 1 g or more can be dissolved in 100 L of solvent.

[0022] The content of (meth)acrylate (a) in the photosensitive resin composition of this disclosure is preferably 1 to 60% by mass, more preferably 2 to 40% by mass, and even more preferably 3 to 20% by mass, when the total content of all (meth)acrylates in the photosensitive resin composition is taken as 100% by mass. A (meth)acrylate (a) content of 1% by mass or more provides sufficient water repellency and scratch resistance to the water-repellent layer. Furthermore, a content of 60% by mass or less ensures sufficient compatibility with other (meth)acrylates, resulting in a water-repellent layer with minimal clouding.

[0023] <(meth)acrylate (b) having an epoxy group> (Meth)acrylate(b) can impart photosensitivity to the water-repellent layer. (Meth)acrylate(b) is not particularly limited as long as it has an epoxy group, but due to its affinity with other (meth)acrylates, the epoxy group should be alicyclic or glycidyl type. It is preferable. Specifically, (meth)acrylate(b) is preferably at least one selected from the group consisting of glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether. One of these epoxy group-containing (meth)acrylate(b) may be used, or two or more may be used in combination.

[0024] The content of (meth)acrylate (b) in the photosensitive resin composition of this disclosure is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and even more preferably 30 to 60% by mass, when the total content of all (meth)acrylates in the photosensitive resin composition is taken as 100% by mass. A (meth)acrylate (b) content of 10% by mass or more improves adhesion to the substrate and durability of the film. Furthermore, a content of 90% by mass or less provides sufficient water repellency and curability.

[0025] <Polyfunctional (meth)acrylate (c)> (Meth)acrylate (c) can enhance the reactivity of each (meth)acrylate in the photosensitive resin composition. (meth)acrylate(c) is not particularly limited as long as it has 6 or more functional (meth)acrylic groups and a weight-average molecular weight of 5000 or less. However, it is preferable that it has a urethane bond, as this makes it easier to design a structure with a large number of (meth)acrylic groups in one molecule and from the viewpoint of affinity with (meth)acrylate(a). It is even more preferable that the urethane bond exists between the terminal (meth)acrylic group and the (meth)acrylic group via an alkyl group.

[0026] Examples of (meth)acrylate(c) include commercially available products such as UA-1100H and UA-6LPA from Shin Nakamura Kogyo Co., Ltd., and MiramerPE210 from Toyo Chemicals Co., Ltd. A single polyfunctional (meth)acrylate(c) may be used, or two or more may be used in combination.

[0027] The content of (meth)acrylate(c) in the photosensitive resin composition of this disclosure is preferably 3 to 60% by mass, more preferably 10 to 55% by mass, and more preferably 30 to 50% by mass, when the total content of all (meth)acrylates in the photosensitive resin composition is taken as 100% by mass. A (meth)acrylate(c) content of 3% by mass or more improves adhesion to the substrate and durability of the film. Furthermore, a content of 60% by mass or less provides sufficient water repellency.

[0028] If a (meth)acrylate may fall under any of (meth)acrylate(a) to (c) of this disclosure, if it may fall under (meth)acrylate(a), it shall be treated as (meth)acrylate(a), even if it may fall under (meth)acrylate(b) or (c). Furthermore, if it does not fall under (meth)acrylate(a) but may fall under both (meth)acrylate(b) and (c), it shall be treated as both (meth)acrylate(b) and (meth)acrylate(c).

[0029] <Thermal radical polymerization initiator (d)> The thermal radical polymerization initiator (d) is not particularly limited, but one with high affinity for (meth)acrylates (a) to (c) is preferred. Furthermore, the thermal radical polymerization initiator (d) is preferably 80°C or lower with a 10-hour half-life temperature. The lower limit of the 10-hour half-life temperature is not particularly limited, but is more preferably 10 to 80°C, and even more preferably 30 to 70°C. If the thermal radical polymerization initiator (d) has a 10-hour half-life temperature of 80°C or lower, the (meth)acrylates can react sufficiently with each other during the formation of the water-repellent layer described later, resulting in sufficient water repellency and film durability. Examples of thermal radical polymerization initiators with a 10-hour half-life temperature of 80°C or lower include azobisisobutyronitrile (AIBN) and, among commercially available products, V-65 (trade name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0030] Furthermore, the content of the thermal radical polymerization initiator (d) in the photosensitive resin composition can be set to any amount so that each (meth)acrylate achieves the target reaction rate. However, from the viewpoint of obtaining a sufficient reaction rate, it is preferable that the content is 0.5 to 10% by mass, and more preferably 0.5 to 5% by mass, when the total content of all (meth)acrylates in the photosensitive resin composition is set to 100% by mass.

[0031] <Photocationic polymerization initiator (e)> The photocationic polymerization initiator (e) is not particularly limited, but a photocationic polymerization initiator that does not contain toxic metals and has high catalytic function that enables low-temperature curing can be suitably used. Specifically, an ionic acid generator can be selected as the photocationic polymerization initiator. The cation of the photocationic polymerization initiator (e) is preferably an onium-based cation with high absorption, and onium ions such as oxonium, ammonium, phosphonium, sulfonium, and iodonium are more preferred, with sulfonium ions being even more preferred among them due to their excellent cationic polymerizability and crosslinking reactivity.

[0032] Furthermore, from the viewpoint of photocationic polymerizability, the molar extinction coefficient of the photocationic polymerization initiator (e) at a wavelength of 365 nm is preferably 0.3 L / (mol·cm) or higher. There is no particular upper limit to the molar extinction coefficient of the photocationic polymerization initiator (e), but it is preferably 0.3 to 5.0 L / (mol·cm), and more preferably 1.0 to 3.0 L / (mol·cm).

[0033] The method for measuring the molar extinction coefficient is as follows: The target compound is dissolved in a solvent that does not absorb at a wavelength of 365 nm, such as acetonitrile, to form a solution. This solution is then placed in a quartz cell, and the absorbance at a wavelength of 365 nm is measured using an ultraviolet-visible air pressure spectrophotometer (manufactured by JASCO). The molar extinction coefficient can be calculated from the obtained absorbance using the following formula. Molar extinction coefficient = absorbance ÷ molar concentration of compound ÷ optical path of cell

[0034] As the photocationic polymerization initiator (e), specifically, at least one selected from the group consisting of 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium, 4-hydroxyphenyl-methyl-benzylsulfonium, 4-hydroxyphenyl-methyl-4-nitrobenzylsulfonium, and diphenyl[4-(phenylthio)phenyl]sulfonium can be preferably used.

[0035] Furthermore, in order to prevent film thinning of the cured (meth)acrylate (b) during the heating process, it is preferable that no HF remains after the exposure / PEB process described later. Specifically, it is preferable to use a photocationic polymerization initiator (e) in which the anion is selected from the group consisting of tetrakis(pentafluorophenyl) gallate and hexafluoroantimonate.

[0036] Furthermore, the content of the photocationic polymerization initiator (e) in the photosensitive resin composition can be set to any amount to achieve the target sensitivity, but from the viewpoint of obtaining sufficient sensitivity, it is preferably in the range of 0.00001 to 0.15 times, more preferably 0.00001 to 0.10 times, and even more preferably 0.01 to 0.10 times, relative to the mass of the epoxy group-containing (meth)acrylate (b).

[0037] <Solvent> The photosensitive resin composition according to this disclosure may contain a solvent as needed from the viewpoint of coatability. Examples of solvents include at least one selected from the group consisting of γ-butyrolactone, ethyl lactate, propylene carbonate, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, butyl acetate, methyl amyl ketone, 2-heptanone, ethyl acetate, methyl ethyl ketone, xylene, and alcohols. One of these solvents may be used, or two or more may be used in combination.

[0038] [Manufacturing method for inkjet recording heads] Next, a method for manufacturing an inkjet recording head using the composition will be described. An example of a method for manufacturing an inkjet recording head according to this disclosure includes a step of forming a water-repellent layer on the surface of an ejection port forming member of an inkjet recording head using the photosensitive resin composition according to this disclosure. An inkjet recording head manufactured by the method according to this disclosure has high water repellency and durability.

[0039] The method for manufacturing an inkjet recording head is not particularly limited, but the following methods can be exemplified. Figure 1 is a schematic perspective view of an inkjet recording head according to one embodiment of the present disclosure. The inkjet recording head has an element substrate 2 having a plurality of energy generating elements 1 for ejecting ink, an ejection port forming member 4 having ejection ports 3 for ejecting ink, a flow path 5 communicating with the ejection ports 3 and holding ink, and a groove 6 formed to reduce internal stress of the ejection port forming member 4. The substrate 2 is also provided with an ink supply port 7 for supplying ink to the flow path 5.

[0040] Figure 2 is a schematic diagram showing the A-A' cross-section of the inkjet recording head shown in Figure 1, representing each stage of the manufacturing process. First, a positive-type photosensitive resin layer containing a positive-type photosensitive resin that serves as a mold for the flow channel is formed on the substrate 2 on which the energy generating element 1 is formed (not shown). The positive-type photosensitive resin is not particularly limited, but in order to prevent the patternability from decreasing due to photosensitivity during exposure of the cationic polymerizable resin layer 9 and the water-repellent layer 10, which will be described later, a material with low absorption to the light used for exposure of the cationic polymerizable resin layer 9 and the water-repellent layer 10 is preferred. For example, if the light is ultraviolet light such as i-rays, a polymethylisopropenyl ketone that can be exposed with DeepUV light can be used as the positive-type photosensitive resin.

[0041] As a method for forming a positive-type photosensitive resin layer, for example, a positive-type photosensitive resin can be dissolved in an appropriate solvent, applied by a spin-coating method, and then pre-baked to form the positive-type photosensitive resin layer. The thickness of the positive-type photosensitive resin layer corresponds to the height of the flow channel and is appropriately determined by the ejection design of the inkjet recording head, but it is preferably 5 to 22 μm.

[0042] Next, the positive-type photosensitive resin layer is patterned to form the mold material 11 (Figure 2(a)). One method for patterning the positive-type photosensitive resin layer is to irradiate the positive-type photosensitive resin layer with an active energy ray that can expose the positive-type photosensitive resin through a mask to perform pattern exposure. After that, the exposed areas of the positive-type photosensitive resin layer are developed using a solvent that can dissolve them, and the mold material 11 can be formed by rinsing.

[0043] Next, a cationic polymerizable resin layer 9 is formed using a resin composition for the discharge port forming member (Figure 2(b)). The resin composition for the discharge port forming member is preferably a composition containing an epoxy resin and a photocationic polymerization initiator, and the epoxy resin is preferably an alicyclic epoxy resin or a glycidyl type epoxy resin. That is, the discharge port forming member is made of epoxy resin and The cured product (B) of a composition containing a photocatalytic polymerization initiator is preferably an alicyclic or glycidyl epoxy resin.

[0044] From the viewpoint of simplifying the manufacturing process and reducing costs, it is desirable that the water-repellent layer and the discharge port be patterned and formed in a single process. Therefore, the epoxy resin is preferably an alicyclic epoxy resin or a glycidyl-type epoxy resin, similar to the water-repellent layer. Furthermore, the same photocationic polymerization initiator as that used for the water-repellent layer can be used.

[0045] In the step of forming the cationic polymerizable resin layer 9, for example, a resin composition for the discharge port forming member may be applied to form a coating film. There are no particular restrictions on the coating method, as long as a uniform film is formed. For example, spin coating or slit coating methods can be used.

[0046] Next, a water-repellent layer 10 is provided to prevent ink accumulation near the discharge port (Figure 2(c)). In the step of forming the water-repellent layer 10, a photosensitive resin composition according to one embodiment of the present disclosure, which forms the water-repellent layer, is applied onto the cationic polymerizable resin layer 9 to form a coating film. For example, a spin coating method or a slit coating method can be used. In addition, the water-repellent layer 10 may be formed by a dry film manufacturing method in order to improve the accuracy of the film thickness.

[0047] After forming a coating film of a photosensitive resin composition for forming a water-repellent layer, the coating film is baked (heated), which promotes the polymerization (curing) reaction of the photosensitive resin composition and forms a water-repellent layer 10.

[0048] In the process of forming the water-repellent layer 10, when the baking is the first heating step, the heating temperature in this step is preferably higher than the 10-hour half-life temperature of the thermal radical polymerization initiator (d) contained in the photosensitive resin composition. More specifically, it is preferably 80°C or higher, and more preferably 90°C or higher. This allows the (meth)acrylates in the water-repellent layer to react sufficiently, providing sufficient water repellency and durability of the film. The heating time is not particularly limited, but for example, it is 1 to 10 minutes.

[0049] Furthermore, generally, these compositions can be made water-repellent by segregating water-repellent groups at the air interface through baking after coating. Also, from the viewpoint of simplifying the manufacturing process and reducing costs, it is preferable to include a step of patterning the resin layer and the water-repellent layer constituting the discharge nozzle forming member in a single step after the step of forming the water-repellent layer. For this reason, it is preferable that these layers are compatible so that the discharge nozzle and the water-repellent layer can be formed at the same time. The step of patterning the resin layer and the water-repellent layer in a single step can be carried out, for example, in the exposure and development steps described later.

[0050] Next, the cationic polymerizable resin layer 9 is exposed (Figure 2(d)). When using a cationic polymerizable resin composition as described above, it is preferable to expose the resin composition at a wavelength at which the photocuring reaction proceeds, and then perform a heating (PEB) step as a second heating step. In this case, in order to further promote the reactivity of the (meth)acrylate in the water-repellent layer, it is preferable to heat the second heating step at a higher temperature than the first heating step. In other words, the step of forming a water-repellent layer includes a first heating step, and the patterning step includes a patterning exposure step and a second heating step, wherein the heating temperature during the second heating step is preferably higher than the heating temperature during the first heating step.

[0051] Next, the exposed cationic polymerizable resin layer 9 is developed to form a fine pattern (Figure 2(e)). This allows the discharge port forming member and the flow channel forming member to be formed from the same material, making peeling at the interface between the members less likely. As the developer used for development, a solvent capable of dissolving uncured epoxy resin is preferred. Specifically, solvents such as propylene glycol monomethyl ether acetate, methyl ethyl ketone, and methyl isobutyl ketone are preferred. It is recommended to use tereol or ketone solvents.

[0052] Furthermore, in order to accelerate the curing of the resin composition, it is preferable to perform the final firing at a temperature higher than the reaction initiation temperature of the thermal radical polymerization initiator (d) after development. Specifically, it is preferable to perform the firing at a temperature of 140°C or higher. After the final firing, the cured product (A) constituting the water-repellent layer preferably has a total reaction rate of 90% or more, and more preferably 95% or more, of the epoxy groups in the photosensitive resin composition forming the water-repellent layer. Furthermore, in the cured product (A), the total reaction rate of the (meth)acrylic groups, based on the total of all (meth)acrylic groups in the (meth)acrylates (a) to (c), preferably has a total reaction rate of 90% or more, and more preferably 95% or more. Furthermore, the pencil hardness of the cured product (A) is preferably 3H or higher, and more preferably 4H or higher. By fulfilling these conditions, sufficient durability can be provided. The reaction rate of the epoxy group and the (meth)acrylic group, as well as the pencil hardness, can be increased, for example, by increasing the amount of photocationic polymerization initiator (e) in the photosensitive resin composition, or by increasing the temperature of the first and second heating steps.

[0053] Similarly, after the final firing, the cured product (B) of the composition constituting the discharge nozzle forming member preferably has a total reaction rate of 90% or more of epoxy groups, based on the total number of epoxy groups in the composition constituting the discharge nozzle forming member, and more preferably 95% or more. Furthermore, the pencil hardness of the hardened product (B) is preferably 3H or higher, and more preferably 4H or higher.

[0054] Next, as shown in Figure 2(f), an ink supply port 7 is formed that penetrates the substrate 2. The ink supply port can be formed by using an etching mask made of a resin composition resistant to etching solutions and performing anisotropic etching. Next, the flow path 5 is formed by removing the mold material 11. Furthermore, if necessary, heat treatment is applied, and components for ink supply (not shown) are joined, and electrical connections (not shown) for driving the energy generating element 1 are made to complete the recording head.

[0055] By using the inkjet head manufacturing method according to one embodiment of this disclosure described above, it becomes possible to manufacture an inkjet recording head in which the ink ejection port and ink flow path are formed with high precision. [Examples]

[0056] The present invention will be described in detail below with reference to examples and comparative examples, but this disclosure is not limited to the configurations embodied in these examples. In addition, the term "part" used in the examples and comparative examples means "parts by mass" unless otherwise specified.

[0057] <Examples 1-18, 21, Comparative Examples 1-7> (Manufacturing of inkjet recording heads) Please refer to Figure 2 for further explanation. First, polymethyl isopropenyl ketone (product name, "ODUR-1010", manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a substrate 2 on which the energy generating element 1 was installed, using a spin-coating method, as a positive-type photosensitive resin that would serve as the mold for the ink channel. A 14 μm thick positive-type photosensitive resin layer was then formed by heat treatment at 120°C for 6 minutes. Next, the ink channel pattern is exposed using the exposure device UX3000 (product name, manufactured by Ushio Inc.), and after developing the exposed area of ​​the positive-type photosensitive resin layer using MIBK (methyl isobutyl ketone), the mold is formed by rinsing with IPA (isopropyl alcohol). Material 11 was formed (Figure 2(a)).

[0058] Next, the resin compositions for the nozzle-forming members shown in each table were applied to the mold material 11 and the substrate 2 by spin coating, and a 25 μm thick cationic polymerizable resin layer 9 was formed by heat treatment at 60°C for 9 minutes (Figure 2(b)). Furthermore, a photosensitive resin composition that forms a water-repellent layer as shown in each table was applied to the cationic polymerizable resin layer 9 to a thickness of 0.5 μm, and as the first heating step, it was heat-treated at 90°C for 3 minutes (Figure 2(c)).

[0059] Next, using a photomask 13, a 4000 J / m² i-line stepper was used to process the surface layer of the cationic polymerizable resin layer 9 so that the resulting openings on the surface of the resin layer 9 had a diameter of approximately 8.3 μm. 2 The sample was exposed to light, and as a second heating step, it was heat-treated at 95°C for 4 minutes (Figure 2(d)). Subsequently, the discharge port 3 was formed by developing the film. The developing process involved developing with a mixture of MIBK and xylene, followed by rinsing with xylene (Figure 2(e)). Furthermore, the film was heated at 140°C for 4 minutes.

[0060] Next, an etching mask was formed on the back surface of substrate 2, and anisotropic etching of the silicon substrate was performed to form the ink supply port 7 (Figure 2(f)). At this time, a protective film (OBC manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the photosensitive resin layer to protect the discharge port formation surface from the etching solution.

[0061] Next, after dissolving and removing the protective film with xylene, a UX-3000 Deep-UV exposure system manufactured by Ushio Inc. was used to expose the material through a negative resist at a rate of 250,000 mJ / cm². 2 The mold material 11 was solubilized by full-surface exposure with the specified exposure dose. Subsequently, it was immersed in methyl lactate while applying ultrasound to dissolve and remove the mold material 11, forming the channel 5. After that, it was fired at a temperature of 200°C. Next, the inkjet recording head was completed by performing assembly processes such as joining components for ink supply (not shown), electrical joining for driving the energy generating element 1 (not shown), and sealing for protecting the electrical joining parts (not shown).

[0062] <Example 19> (Manufacturing of inkjet recording heads) In Example 19, a resin composition that forms a water-repellent layer as shown in Table 4 was used, and the first heating step after coating was a heat treatment at 60°C for 3 minutes. The rest of the process was the same as in Example 1.

[0063] <Example 20> (Manufacturing of inkjet recording heads) In Example 20, the second heating step after exposure was a heat treatment at 60°C for 4 minutes. Otherwise, the preparation was carried out in the same manner as in Example 1.

[0064] <Examples 1-21, Comparative Examples 1-7> (Method for measuring the weight-average molecular weight (Mw) of methacrylate) We use the Tosoh HLC-8220GPC system as a gel permeation chromatography apparatus. The analysis was performed using TSKgel SuperHZ2000, TSKgel SuperHZ3000, and TSKgel SuperHZ4000 columns from Tosoh Corporation, connected in series. Detection was performed using a refractometer (RI), with one TSKgel SuperH-RC column used as the reference column. Tetrahydrofuran from Wako Pure Chemical Industries, Ltd. was used as the developing solvent, and the flow rate for both the column and the reference column was set to 0.35 mL / min. The measurement temperature was 40°C for both the plunger pump and the column. For sample preparation, 0.025 g of each (meth)acrylate was diluted in 10 mL of tetrahydrofuran, and 25 μL of this solution was injected. For molecular weight distribution calculations, TSKgel standard material from Tosoh Corporation was used. We used polystyrene variants #C, D, E, and F.

[0065] (Method for evaluating response rate) • Epoxy group The reaction rate of the epoxy group was calculated using the peak area derived from the epoxy group, based on the absorbance spectrum of the water-repellent layer surface of the inkjet recording head obtained by Fourier transform infrared spectroscopy (FT-IR). The peak area derived from the epoxy group was obtained at wavenumber 910 cm⁻¹. -1 For the peaks originating from nearby epoxy groups, the integral value was used with the baseline set to a line connecting the nearest minimums to the left and right of this peak. Specifically, the epoxy group reaction rate E (%) was calculated using the following formula, where X is the peak area in the absorbance spectrum of the composition constituting the water-repellent layer surface before exposure, and Y is the peak area in the absorbance spectrum after exposure. E(%) = [(XY) / X] × 100

[0066] (meth)acrylic group The reaction rate of the (meth)acrylic group was calculated using the peak area derived from the (meth)acrylic group, based on the absorbance spectrum of the water-repellent layer surface of the inkjet recording head obtained by FT-IR. The peak area derived from the (meth)acrylic group was found at wavenumbers 1500 to 1610 cm⁻¹. -1For the peaks originating from the (meth)acrylic groups located nearby, the integral value was used with the baseline being the line connecting the nearest minima to the left and right of this peak. Specifically, the (meth)acrylic group reaction rate A (%) was calculated using the following formula, where X is the peak area in the absorbance spectrum of the composition constituting the surface of the water-repellent layer before baking the water-repellent layer coating, and Y is the peak area in the absorbance spectrum after exposure. A(%) = [(XY) / X] × 100

[0067] (Method for evaluating pencil hardness / water repellency) ·Pencil hardness A pencil hardness test was performed on the water-repellent surface of the inkjet recording head. Specifically, the degree of scratching on the water-repellent layer was examined using a pencil hardness tester specified in JIS K 5600, and the pencil hardness was measured.

[0068] • Water repellency (evaluation of water repellency in the initial stage and after abrasion) The micro-contact angle was evaluated for the water-repellent layer surface of an inkjet recording head. A micro-contact angle meter (product name: DropMeasure®, manufactured by Microjet Co., Ltd.) was used. The dynamic receding contact angle θr1 of the water-repellent layer surface with respect to pure water and the dynamic receding contact angle θr2 of the water-repellent layer surface after a wiper rubbing test were measured. In the wiper rubbing test, a pigment dispersion with a pigment concentration of 10% was dropped onto a substrate, and a wiper (material: hydrogenated nitrile rubber (HNBR), rubber hardness: JIS-A hardness 75) was used to rub the substrate back and forth 2000 times with a pressing load of 0.098 N (10 gf) between the wiper and the substrate.

[0069] (Evaluation method for inkjet print heads) The resin pigment dispersion ink for evaluation was injected into a tank, and the printing characteristics were evaluated. For printing evaluation, the arithmetic mean of the deviation of the ink from the target impact position was defined as the impact accuracy, and the evaluation was performed according to the following criteria. A: Impact accuracy of 3μm or less B: Impact accuracy of 5μm or less C: Impact accuracy of 7μm or less D: Impact accuracy exceeds 7μm

[0070] (Evaluation results) The results are shown in Tables 1-6. All examples showed excellent water repellency and pattern accuracy, and good printing performance was also obtained. In particular, the printing quality of Examples 1, 3, and 4 was excellent. On the other hand, the printing quality was reduced in Comparative Examples 1-7.

[0071] The details of the trade names or compound names used as raw materials in each table are as follows: (Acrylate (a)) • AD-1700: "Fluorolink (registered trademark) PFPE AD1700," manufactured by Solvay Specialty Polymers, PFPE-urethane acrylate, Mw=3973, 4 functional groups. • DAC-HP: "Optoul (registered trademark) DAC-HP," manufactured by Daikin Industries, Ltd., fluorine-containing acrylate, Mw=1621, 2 functional groups. • M-1620: "Polyflon (registered trademark) PTFE M-1620," manufactured by Daikin Industries, Ltd., fluorine-containing methacrylate, Mw=214, 1 functional group.

[0072] (Acrylate (b)) Glycidyl methacrylate: Manufactured by Tokyo Chemical Industry Co., Ltd., Mw=142, 1 functional group.

[0073] (Acrylate (c)) • UA-1100H: "NK Oligo UA-1100H" manufactured by Shin Nakamura Kogyo Co., Ltd., urethane acrylate, Mw=800, 6 functional groups. • UA-6LPA: "NK Oligo U-6LPA" manufactured by Shin-Nakamura Kogyo Co., Ltd., urethane acrylate, Mw=850, 6 functional groups. • EBECRYL 3603: "EBECRYL (registered trademark) 3603" manufactured by Daicel Ornex Co., Ltd., novolac epoxy acrylate, Mw=760, 3 functional groups. • UA-16HA: "NK Oligo UA-16HA" manufactured by Shin Nakamura Kogyo Co., Ltd., urethane acrylate, Mw=2300, 6 functional groups. • MiramerPE210: "MiramerPE210" manufactured by Toyo Chemicals Co., Ltd., Mw=620, 2 functional groups. • UV-7605B: "Shiko (registered trademark) UV-7605B," manufactured by Mitsubishi Chemical Corporation, urethane acrylate, Mw=11000, 6 functional groups.

[0074] (Thermal radical polymerization initiator (d)) • V-65: "V-65" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., azo polymerization initiator, 10-hour half-life temperature = 65°C • V-086: "V-086" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., azo polymerization initiator, 10-hour half-life temperature = 86°C

[0075] (Photocationic polymerization initiator (e)) • SP-172: "ADEKA Arclus SP-172" manufactured by ADEKA Corporation, photocationic polymerization initiator, anionic structure = hexafluoroantimonate, molar extinction coefficient = 1.6 L / (mol·cm) • CPI-110A: "CPI(registered trademark)-110A" manufactured by Sunapro Co., Ltd., photocationic polymerization initiator, anionic structure = hexafluoroantimonate, molar extinction coefficient = 0.16 L / (mol·cm) • TPS-1000: "TPS-1000" manufactured by Midori Chemical Co., Ltd., photocationic polymerization initiator, anionic structure = trifluoromethanesulfonate, molar extinction coefficient = 0 L / (mol·cm)

[0076] (Epoxy resin) • EHPE-3150: "EHPE3150" manufactured by Daicel Corporation, alicyclic epoxy resin • jER157S70: "jER(registered trademark) 157S70" is a phenol novolac type epoxy resin manufactured by Mitsubishi Chemical Corporation.

[0077] (solvent) • MIBK: "4-methyl-2-pentanone" manufactured by Kishida Chemical Co., Ltd. • OMR Thinner: "OMR Thinner" manufactured by Tokyo Ohka Kogyo Co., Ltd.

[0078] [Table 1]

[0079] [Table 2]

[0080] [Table 3]

[0081] [Table 4]

[0082] [Table 5]

[0083] [Table 6]

[0084] This disclosure relates to the following configuration and method. (Composition 1) An inkjet recording head, wherein the inkjet recording head is substrate, A discharge port forming member provided on the substrate, and The discharge port forming member has a water-repellent layer provided on it, The water-repellent layer consists of a cured product (A) of a photosensitive resin composition. The photosensitive resin composition is (a) a (meth)acrylate having a perfluoropolyether group, (b) an epoxy group-containing (meth)acrylate, Polyfunctional (meth)acrylate (c), Thermal radical polymerization initiator (d) and Contains a photocationic polymerization initiator (e), The (meth)acrylate (a) is a (meth)acrylate having three or more functional (meth)acrylic groups, The polyfunctional (meth)acrylate (c) is a (meth)acrylate having 6 or more functional (meth)acrylic groups and a weight-average molecular weight of 5000 or less. An inkjet recording head characterized by the following features. (Configuration 2) The inkjet recording head according to configuration 1, wherein the weight-average molecular weight of the (meth)acrylate (a) is 5000 or less. (Composition 3) The inkjet recording head according to configuration 1 or 2, wherein the (meth)acrylate (a) has a (meth)acrylate structure at both ends. (Composition 4) The inkjet recording head according to any one of configurations 1 to 3, wherein the (meth)acrylate (a) has a urethane bond. (Composition 5) An inkjet recording head according to any of configurations 1 to 4, wherein the (meth)acrylate (a) is a compound represented by formula (1): [ka] In formula (1), a and b are each independent integers between 0 and 2; c is the average number of repeats of the repeating unit -(CF2CF2O)-, and d is the average number of repeats of the repeating unit -(CF2O)-, where c and d are each independent numbers greater than or equal to 0 and satisfy 15 ≤ (c + d) ≤ 25; if both repeating units are present, these repeating units may be block bonds, random bonds, or a combination of block bonds and random bonds; Y each independently represents a group represented by the following formula (Y1) or formula (Y2), and X each independently represents an alkylene group with 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms; [ka] [ka] In equations (Y1) and (Y2), R 1 and R 2 Each of these independently represents either a hydrogen atom or a methyl group. (Composition 6) An inkjet recording head according to any one of configurations 1 to 5, wherein the (meth)acrylate (a) is soluble in an organic solvent. (Composition 7) The inkjet recording head according to configuration 6, wherein the organic solvent is a ketone solvent. (Composition 8) An inkjet recording head according to any one of configurations 1 to 7, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (a) in the photosensitive resin composition is 1 to 60% by mass. (Composition 9) An inkjet recording head according to any one of configurations 1 to 8, wherein the epoxy group of the (meth)acrylate (b) is of the alicyclic or glycidyl type. (Composition 10) An inkjet recording head according to any one of configurations 1 to 9, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (b) in the photosensitive resin composition is 10 to 90% by mass. (Composition 11) An inkjet recording head according to any one of configurations 1 to 10, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (c) in the photosensitive resin composition is 3 to 60% by mass. (Composition 12) An inkjet recording head according to any one of configurations 1 to 11, wherein the 10-hour half-life temperature of the thermal radical polymerization initiator (d) is 80°C or lower. (Composition 13) An inkjet recording head according to any one of configurations 1 to 12, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of the thermal radical polymerization initiator (d) is 0.5 to 10% by mass. (Composition 14) An inkjet recording head according to any one of configurations 1 to 13, wherein the cation of the photocationic polymerization initiator (e) is a sulfonium ion. (Composition 15) An inkjet recording head according to any one of configurations 1 to 14, wherein the molar extinction coefficient of the photocationic polymerization initiator (e) at a wavelength of 365 nm is 0.3 L / (mol·cm) or more. (Composition 16) The inkjet recording head according to any one of configurations 1 to 15, wherein the anion of the photocationic polymerization initiator (e) is at least one selected from the group consisting of tetrakis(pentafluorophenyl) gallate and hexafluoroantimonate. (Composition 17) An inkjet recording head according to any one of configurations 1 to 16, wherein the content of the photocationic polymerization initiator (e) in the photosensitive resin composition is 0.00001 to 0.15 times the mass of the (meth)acrylate (b). (Composition 18) The inkjet recording head according to any one of configurations 1 to 17, wherein the discharge port forming member is a cured product (B) of a composition containing an epoxy resin and a photocationic polymerization initiator, and the epoxy resin is an alicyclic or glycidyl type epoxy resin. (Composition 19) In the cured product (A), all of the (meth)acrylates (a) to (c) An inkjet recording head according to any of configurations 1 to 18, wherein the reaction rate of the total (meth)acrylic groups, based on the total number of acrylic groups, is 90% or more. (Composition 20) An inkjet recording head according to any one of configurations 1 to 19, wherein in the cured product (A), the reaction rate of the total epoxy groups, based on the total number of epoxy groups in the photosensitive resin composition, is 90% or more. (Composition 21) An inkjet recording head according to any of configurations 1 to 20, wherein the hardened material (A) has a pencil hardness of 3H or higher. (Composition 22) An inkjet recording head according to any of configurations 1 to 21, wherein the hardened material (A) has a pencil hardness of 4H or higher. (Method 1) A method for manufacturing an inkjet recording head, wherein the inkjet recording head is substrate and It has a discharge port forming member provided on the substrate, The manufacturing method includes a step of forming a water-repellent layer on the discharge nozzle forming member, The resin composition that forms the water-repellent layer is (a) a (meth)acrylate having a perfluoropolyether group, (b) an epoxy group-containing (meth)acrylate, Polyfunctional (meth)acrylate (c), Thermal radical polymerization initiator (d) and Contains a photocationic polymerization initiator (e), The (meth)acrylate (a) is a (meth)acrylate having three or more functional (meth)acrylic groups, The polyfunctional (meth)acrylate (c) includes a (meth)acrylate with an average molecular weight of 5000 or less having 6 or more (meth)acrylic groups. A method for manufacturing an inkjet recording head, characterized by the above. (Method 2) The step of forming the water-repellent layer includes a first heating step, A method for manufacturing an inkjet recording head according to Method 1, wherein the heating temperature during the first heating step is higher than the 10-hour half-life temperature of the thermal radical polymerization initiator (d). (Method 3) A method for manufacturing an inkjet recording head according to method 1 or 2, comprising the step of patterning the resin layer constituting the discharge port forming member and the water-repellent layer together after the step of forming the water-repellent layer. (Method 4) The step of forming the water-repellent layer includes a first heating step, The patterning step includes a patterning exposure step and a second heating step, A method for manufacturing an inkjet recording head according to Method 3, wherein the heating temperature during the second heating step is higher than the heating temperature during the first heating step. [Explanation of symbols]

[0085] 1: Element 2: Substrate 3: Discharge port 4: Discharge port forming member 5: Flow path 6: Groove 7: Supply port 9: Cationic polymerizable resin layer 10: Water-repellent layer 11: Mold 12: Unexposed area 13: Photomask 14:Exposed part

Claims

1. An inkjet recording head, wherein the inkjet recording head is substrate, A discharge port forming member provided on the substrate, and The discharge port forming member has a water-repellent layer provided on it, The water-repellent layer consists of a cured product (A) of a photosensitive resin composition. The photosensitive resin composition is (a) a (meth)acrylate having a perfluoropolyether group, (b) (meth)acrylate having an epoxy group, Polyfunctional (meth)acrylate (c), Thermal radical polymerization initiator (d) and Contains a photocationic polymerization initiator (e), The (meth)acrylate (a) is a (meth)acrylate having three or more functional (meth)acrylic groups, The polyfunctional (meth)acrylate (c) is a (meth)acrylate having six or more functional (meth)acrylic groups and a weight-average molecular weight of 5000 or less. An inkjet recording head characterized by the following features.

2. The inkjet recording head according to claim 1, wherein the weight-average molecular weight of the (meth)acrylate (a) is 5000 or less.

3. The inkjet recording head according to claim 1 or 2, wherein the (meth)acrylate (a) has a (meth)acrylate structure at both ends.

4. The inkjet recording head according to claim 1 or 2, wherein the (meth)acrylate (a) has a urethane bond.

5. The inkjet recording head according to claim 1 or 2, wherein the (meth)acrylate (a) is a compound represented by formula (1): In equation (1), a and b are independent integers between 0 and 2; c is the repeating unit - (CF ２ CF ２ O) is the average number of repetitions, and d is the repetition unit - (CF ２ O) The average number of repeating units, where c and d each independently represent a number greater than or equal to 0, and satisfying 15 ≤ (c + d) ≤ 25; if both repeating units are present, these repeating units may be block bonds, random bonds, or a combination of block bonds and random bonds; Y each independently represents a group represented by the following formula (Y1) or formula (Y2), and X each independently represents an alkylene group with 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms; In equations (Y1) and (Y2), R １ and R ２ Each of these independently represents either a hydrogen atom or a methyl group.

6. The inkjet recording head according to claim 1 or 2, wherein the (meth)acrylate (a) is soluble in an organic solvent.

7. The inkjet recording head according to claim 6, wherein the organic solvent is a ketone solvent.

8. The inkjet recording head according to claim 1 or 2, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (a) in the photosensitive resin composition is 1 to 60% by mass.

9. The inkjet recording head according to claim 1 or 2, wherein the epoxy group of the (meth)acrylate (b) is alicyclic or glycidyl type.

10. The inkjet recording head according to claim 1 or 2, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (b) in the photosensitive resin composition is 10 to 90% by mass.

11. The inkjet recording head according to claim 1 or 2, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of (meth)acrylate (c) in the photosensitive resin composition is 3 to 60% by mass.

12. The inkjet recording head according to claim 1 or 2, wherein the 10-hour half-life temperature of the thermal radical polymerization initiator (d) is 80°C or lower.

13. The inkjet recording head according to claim 1 or 2, wherein, when the total content of all (meth)acrylates in the photosensitive resin composition is 100% by mass, the content of the thermal radical polymerization initiator (d) is 0.5 to 10% by mass.

14. The inkjet recording head according to claim 1 or 2, wherein the cation of the photocationic polymerization initiator (e) is a sulfonium ion.

15. The inkjet recording head according to claim 1 or 2, wherein the molar extinction coefficient of the photocationic polymerization initiator (e) at a wavelength of 365 nm is 0.3 L / (mol·cm) or more.

16. The inkjet recording head according to claim 1 or 2, wherein the anion of the photocationic polymerization initiator (e) is at least one selected from the group consisting of tetrakis(pentafluorophenyl) gallate and hexafluoroantimonate.

17. The inkjet recording head according to claim 1 or 2, wherein the content of the photocationic polymerization initiator (e) in the photosensitive resin composition is 0.00001 to 0.15 times the mass of the (meth)acrylate (b).

18. The inkjet recording head according to claim 1 or 2, wherein the discharge port forming member is a cured product (B) of a composition containing an epoxy resin and a photocationic polymerization initiator, and the epoxy resin is an alicyclic or glycidyl type epoxy resin.

19. The inkjet recording head according to claim 1 or 2, wherein in the cured product (A), the reaction rate of the total (meth)acrylic groups, based on the total of all (meth)acrylic groups of the (meth)acrylates (a) to (c), is 90% or more.

20. The inkjet recording head according to claim 1 or 2, wherein in the cured product (A), the reaction rate of the total epoxy groups, based on the total number of epoxy groups in the photosensitive resin composition, is 90% or more.

21. The inkjet recording head according to claim 1 or 2, wherein the pencil hardness of the cured product (A) is 3H or higher.

22. The inkjet recording head according to claim 1 or 2, wherein the hardened material (A) has a pencil hardness of 4H or higher.

23. A method for manufacturing an inkjet recording head, wherein the inkjet recording head is substrate and It has a discharge port forming member provided on the substrate, The manufacturing method includes a step of forming a water-repellent layer on the discharge nozzle forming member, The resin composition that forms the water-repellent layer is (a) a (meth)acrylate having a perfluoropolyether group, (b) (meth)acrylate having an epoxy group, Polyfunctional (meth)acrylate (c), Thermal radical polymerization initiator (d) and Contains a photocationic polymerization initiator (e), The (meth)acrylate (a) is a (meth)acrylate having three or more functional (meth)acrylic groups, The polyfunctional (meth)acrylate (c) includes a (meth)acrylate with an average molecular weight of 5000 or less having 6 or more (meth)acrylic groups. A method for manufacturing an inkjet recording head, characterized by the above.

24. The step of forming the water-repellent layer includes a first heating step, A method for manufacturing an inkjet recording head according to claim 23, wherein the heating temperature during the first heating step is higher than the 10-hour half-life temperature of the thermal radical polymerization initiator (d).

25. A method for manufacturing an inkjet recording head according to claim 23 or 24, further comprising the step of patterning the resin layer constituting the discharge port forming member and the water-repellent layer together after the step of forming the water-repellent layer.

26. The step of forming the water-repellent layer includes a first heating step, The patterning step includes a patterning exposure step and a second heating step, The method for manufacturing an inkjet recording head according to claim 25, wherein the heating temperature during the second heating step is higher than the heating temperature during the first heating step.

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