JP7723726B2 - Antifouling film manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an anti-fouling film.

In recent years, with the widespread use of mobile devices such as tablets and smartphones, there has been an increasing demand for protecting these devices from dirt and other contaminants. For example, an anti-fouling film with an anti-fouling layer is typically attached to the surface of a display equipped with a touch panel to ensure visibility while reducing the effects of contamination from the external environment (fingerprints, fingerprints, dust, etc.).

Patent Document 1 discloses, as an example of an anti-fouling film, an anti-reflection film in which an anti-fouling layer is provided on an anti-reflection layer. Patent Document 1 also describes a method for forming the anti-fouling layer, in which an anti-fouling agent composition prepared by diluting a fluorine-containing silicon compound (anti-fouling agent) with perfluorohexane is used, and the anti-fouling layer is formed on the anti-reflection layer by vacuum deposition. Furthermore, such anti-fouling films are manufactured, for example, by a roll-to-roll method while transporting a work film (see, for example, Patent Document 2).

JP 2011-69995 A Japanese Patent Application Laid-Open No. 2022-63374

When using an antifouling composition containing a fluorine-based solvent such as perfluorohexane, typically, at least a portion of the fluorine-based solvent in the antifouling composition is removed by degassing, and the degassed antifouling composition is then used as the deposition material to form an antifouling layer by vacuum deposition. Furthermore, when forming an antifouling layer by roll-to-roll vacuum deposition, the deposition material in the vacuum deposition device gradually decreases from the start of transport (deposition start) to the end of transport (deposition end). However, by gradually increasing the deposition temperature, the decrease in the deposition amount due to the decrease in deposition material is suppressed, and the film thickness of the antifouling layer is maintained constant.

However, when an anti-fouling layer is formed using roll-to-roll vacuum deposition, the anti-fouling properties of the layer formed at a relatively low deposition temperature (the initial stage after the start of transport) tend to deteriorate. In anti-fouling film rolls obtained using roll-to-roll manufacturing methods, areas with reduced anti-fouling properties are discarded if they do not meet quality control standards. For this reason, it is difficult to prevent a decrease in yield when forming an anti-fouling layer using roll-to-roll vacuum deposition.

In light of the above, the present invention aims to provide a method for manufacturing an anti-fouling film that can suppress a decrease in yield when forming an anti-fouling layer using a roll-to-roll vacuum deposition method.

<Aspects of the present invention>
The present invention includes the following aspects.

[1] A method for manufacturing an antifouling film, in which an antifouling layer is formed on one main surface of a workpiece film by a vacuum deposition method while the workpiece film is transported by a roll-to-roll method,
a step Sa of degassing an antifouling composition containing a fluorine-based solvent under a reduced pressure atmosphere at a temperature of 150° C. or higher and 250° C. or lower before forming the antifouling layer;
The antifouling layer is formed using the antifouling agent composition degassed in the step Sa as a deposition material.

[2] The method for producing an antifouling film described in [1] above, wherein the antifouling agent composition contains a fluorine-containing compound as an antifouling agent.

[3] The method for producing an antifouling film described in [2] above, wherein the fluorine-containing compound is an alkoxysilane compound containing a perfluoropolyether skeleton.

[4] The work film includes an inorganic oxide layer,
The method for producing an antifouling film according to any one of [1] to [3], wherein the antifouling layer is formed on one main surface of the inorganic oxide layer.

[5] The inorganic oxide layer includes a silicon oxide layer,
The method for producing an antifouling film according to [4], wherein the antifouling layer is formed on one main surface of the silicon oxide layer.

[6] The method for producing an antifouling film according to any one of [1] to [5] above, wherein the degree of vacuum when forming the antifouling layer is 9.0×10 ⁻³ Pa or less.

[7] The method for producing an antifouling film described in any one of [1] to [6], wherein in step Sa, degassing is performed under a reduced pressure atmosphere of 40 Pa or less.

[8] The method for producing an antifouling film described in any one of [1] to [7] above, further comprising, before step Sa, a step of reducing the pressure of the atmosphere surrounding the antifouling agent composition to a temperature of 30°C or less.

The present invention provides a method for manufacturing an antifouling film that can suppress a decrease in yield when forming an antifouling layer using a roll-to-roll vacuum deposition method.

1 is a structural diagram showing an example of a vacuum deposition apparatus that can be used in the method for producing an antifouling film according to the present invention. 1 is a cross-sectional view showing an example of a work film that can be used in the antifouling film manufacturing method of the present invention. 1 is a cross-sectional view showing an example of an antifouling film obtained by the production method of the present invention.

Preferred embodiments of the present invention are described in detail below, but the present invention is not limited to these. Furthermore, all academic and patent literature cited in this specification is incorporated herein by reference.

First, let us explain the terms used in this specification. "Refractive index" refers to the refractive index for light with a wavelength of 550 nm in an atmosphere at 23°C. "Workpiece film" refers to a film having a layered structure immediately before the anti-fouling layer is formed. The "main surface" of a layered material (more specifically, workpiece film, transparent film substrate, hard coat layer, primer layer, anti-reflection layer, anti-fouling layer, etc.) refers to the surface perpendicular to the thickness direction of the layered material. Unless otherwise specified, the "thickness (film thickness)" value of each layer constituting the anti-fouling film is the arithmetic mean value of 10 measurements obtained by randomly selecting 10 measurement points from an image of a cross section cut through the layer in the thickness direction and measuring the thickness at the selected 10 measurement points. "Vacuum degree" is a measure of how close the material is to an ideal vacuum (pressure: 0 Pa) and is expressed as the pressure of residual gas.

Unless otherwise specified, the number-average primary particle diameter of particles is the number-average value of the equivalent circle diameter (Heywood diameter: the diameter of a circle having the same area as the projected area of a primary particle) of 100 primary particles measured using a scanning electron microscope and image processing software (e.g., "ImageJ" manufactured by the National Institutes of Health).

"Solids" refers to non-volatile components in the composition, such as components other than the solvent.

Hereinafter, the compound name may be followed by "system" to refer to the compound and its derivatives in a comprehensive manner. Furthermore, when the compound name is followed by "system" to refer to the name of a polymer, unless otherwise specified, it means that the repeating unit of the polymer is derived from the compound or its derivative. Furthermore, acrylates and methacrylates may be referred to in a comprehensive manner as "(meth)acrylates."

Unless otherwise specified, the components, functional groups, etc. exemplified in this specification may be used alone or in combination of two or more types.

The drawings referenced in the following description primarily show each component in a schematic manner for ease of understanding, and the size, number, shape, etc. of each component shown may differ from the actual size due to the convenience of creating the drawings. Furthermore, for the sake of convenience, in drawings described later, components that are the same as those in previously described drawings may be assigned the same reference numerals, and their description may be omitted.

<Method of manufacturing antifouling film>
The method for producing an antifouling film according to this embodiment includes a step of forming an antifouling layer on one main surface of a workpiece film by vacuum deposition while the workpiece film is transported in a roll-to-roll manner (hereinafter, this step may be referred to as the "deposition step"). The method for producing an antifouling film according to this embodiment also includes a step Sa, prior to the deposition step, of degassing an antifouling composition containing a fluorinated solvent in a reduced pressure atmosphere at a temperature of 150°C to 250°C. Hereinafter, this step Sa may be referred to as the "degassing step." In this embodiment, the deposition step forms an antifouling layer using the antifouling composition degassed in the degassing step as a deposition material.

Examples of anti-fouling films obtained using the manufacturing method according to this embodiment include anti-reflection films with an anti-fouling layer, gas barrier films with an anti-fouling layer, and transparent conductive films with an anti-fouling layer.

The antifouling film manufacturing method according to this embodiment can suppress a decrease in yield when forming an antifouling layer using a roll-to-roll vacuum deposition method. The reason for this is presumed to be as follows.

As mentioned above, when an anti-fouling layer is formed using a typical roll-to-roll vacuum deposition method, the anti-fouling properties (more specifically, anti-fouling ability, slide resistance, scratch resistance, etc.) of the anti-fouling layer formed at a relatively low deposition temperature (the initial stage from the start of transport) tend to be reduced. This reduction in anti-fouling properties is thought to be due to the incorporation of fluorinated solvents and impurities derived from fluorinated solvents (hereinafter collectively referred to as "residual components") remaining in the deposition material into the formed anti-fouling layer. In other words, because a relatively large amount of residual components remains in the deposition material at a relatively low deposition temperature, the amount of residual components in an anti-fouling layer formed at a relatively low deposition temperature tends to be relatively large. Therefore, anti-fouling layers formed at a relatively low deposition temperature tend to have reduced anti-fouling properties due to the influence of the residual components.

In contrast, in this embodiment, a degassing step is performed prior to the vapor deposition step, in which the antifouling composition containing a fluorinated solvent is degassed in a reduced pressure atmosphere at a temperature of 150°C or higher, allowing residual components to be sufficiently removed. Furthermore, the upper limit of the heating temperature in the degassing step is set to 250°C, preventing the active ingredient (antifouling agent) in the antifouling composition from being removed during the degassing step. For these reasons, in this embodiment, antifouling properties can be ensured even for an antifouling layer formed at a relatively low vapor deposition temperature. Therefore, the method for producing an antifouling film according to this embodiment can prevent a decrease in yield when forming an antifouling layer by roll-to-roll vacuum vapor deposition.

In the degassing step of this embodiment, in order to further reduce the amount of active ingredient removed from the antifouling composition, the heating temperature (degassing temperature) in the degassing step is preferably 240°C or less, more preferably 230°C or less, even more preferably 220°C or less, and may be 210°C or less, 200°C or less, 190°C or less, 180°C or less, 170°C or less, or 160°C or less.

The method for manufacturing an antifouling film according to this embodiment may include other steps (other steps) in addition to the degassing step and the vapor deposition step. Examples of other steps include the "exhaust step" and "excess antifouling agent removal step" described below. An example of a method for manufacturing an antifouling film according to this embodiment will be described below, with reference to the accompanying drawings. Figure 1, which will be referred to, is a structural diagram showing an example of a vacuum vapor deposition apparatus that can be used in the method for manufacturing an antifouling film according to this embodiment.

[Vacuum deposition device]
The vacuum deposition apparatus shown in Fig. 1 is a roll-to-roll type vacuum deposition apparatus, and includes a chamber 10, and a guide roll 11, a film-forming roll 12, a guide roll 13, and a crucible 14 arranged in the chamber 10. The crucible 14 is provided vertically below the film-forming roll 12. An antifouling agent composition 15 is placed in the crucible 14.

When forming an anti-fouling layer on the workpiece film 20, the film-forming roll 12 is rotated counterclockwise by a drive unit (not shown), and the workpiece film 20 is guided by the guide roll 11 and transported to the film-forming roll 12. After the anti-fouling layer is formed on the main surface 20a of the workpiece film 20 opposite the film-forming roll 12, the workpiece film 20 with the anti-fouling layer formed is guided by the guide roll 13 and transported outside the chamber 10. An example of the workpiece film 20 will be described later.

The antifouling composition 15 contains an active ingredient (antifouling agent) and a fluorine-based solvent. In order to enhance antifouling properties, a fluorine-containing compound is preferred as the antifouling agent. When the antifouling agent is a fluorine-containing compound, the fluorine-based solvent in the antifouling composition 15 plays a role in suppressing decomposition of the antifouling agent. Among fluorine-containing compounds, alkoxysilane compounds containing a perfluoropolyether skeleton are preferred because they have excellent water repellency and can exhibit high antifouling properties. Examples of alkoxysilane compounds containing a perfluoropolyether skeleton include alkoxysilane compounds having a plurality of linear or branched perfluoroalkylene oxide units having from 1 to 4 carbon atoms. Examples of the linear or branched perfluoroalkylene oxide unit having from 1 to 4 carbon atoms include a perfluoromethylene oxide unit (-CF ₂ O-), a perfluoroethylene oxide unit (-CF ₂ CF ₂ O-), a perfluoropropylene oxide unit (-CF ₂ CF ₂ CF ₂ O-), a perfluoroisopropylene oxide unit (-CF(CF ₃ )CF ₂ O-), and the like.

Examples of the fluorine-based solvent contained in the antifouling agent composition 15 include perfluoroalkanes (more specifically, perfluorohexane, etc.) and hydrofluoroethers. Examples of hydrofluoroethers include C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , C ₆ F ₁₃ OCH ₃ , C ₃ HF ₆ —CH(CH ₃ )O—C ₃ HF ₆ , etc.

The content of the active ingredient (antifouling agent) in the antifouling composition 15 before carrying out the evacuation step described below is, for example, 5% by weight or more and 80% by weight or less, and preferably 10% by weight or more and 50% by weight or less, based on the total amount of the antifouling composition 15.

The above describes an example of a vacuum deposition device that can be used in the method for manufacturing an antifouling film according to this embodiment, but the vacuum deposition device that can be used in the present invention is not limited to the vacuum deposition device shown in Figure 1. In the present invention, for example, the vacuum deposition device described in JP 2022-63374 A may also be used.

Next, we will explain each process included in an example of a method for manufacturing an antifouling film according to this embodiment. Note that in the following example, the exhaust process and degassing process are performed without transporting the workpiece film 20.

[Exhaust process]
The exhaust step is a step of reducing the pressure of the atmosphere surrounding the antifouling composition 15 (the atmosphere inside the chamber 10) to a temperature of 30° C. or less, and this step exhausts the gas inside the chamber 10 to the outside of the chamber 10. The exhaust step is carried out before the degassing step. The exhaust step can remove water vapor and the like from the atmosphere inside the chamber 10, thereby suppressing decomposition of the active ingredient (e.g., fluorine-containing compound) due to moisture.

To further suppress decomposition of the active ingredient, the ambient temperature within chamber 10 during the exhaust process is preferably 25°C or lower. There is no particular limitation on the lower limit of the ambient temperature within chamber 10 during the exhaust process, but it is, for example, 10°C or higher.

The decompression conditions for the evacuation step are not particularly limited, as long as they are conditions that allow water vapor and the like to be removed from the atmosphere within chamber 10. However, in order to effectively remove water vapor and the like, it is preferable to decompress the atmosphere within chamber 10 at a pressure of 40 Pa or less, and more preferably at a pressure of 35 Pa or less. Furthermore, in order to increase productivity by shortening the decompression time (the time it takes to decompress from normal pressure to a predetermined decompression condition) during the evacuation step, it is preferable to decompress the atmosphere within chamber 10 at a pressure of 20 Pa or more, and more preferably at a pressure of 25 Pa or more. The evacuation step is carried out, for example, by lowering the pressure within chamber 10 continuously or in stages.

[Degassing process]
The degassing step is a step of degassing the antifouling composition 15 in the crucible 14 under a reduced pressure atmosphere at a temperature of 150°C or higher and 250°C or lower. The reduced pressure conditions in the degassing step are not particularly limited as long as they are conditions that allow the removal of residual components in the antifouling composition 15. However, in order to effectively remove the residual components, it is preferable to reduce the pressure of the atmosphere in the chamber 10 under conditions of 40 Pa or lower, and more preferably under conditions of 30 Pa or lower. Furthermore, in order to increase productivity by shortening the decompression time (the time required to reduce the pressure to a predetermined reduced pressure condition) in the degassing step, it is preferable to reduce the pressure of the atmosphere in the chamber 10 under conditions of 5 Pa or higher. Note that the degassing step may be performed while continuously or stepwise reducing the pressure in the chamber 10, or may be performed while maintaining the pressure in the chamber 10 at a constant reduced pressure.

In order to effectively remove residual components from the antifouling composition 15 while increasing productivity, the degassing time in the degassing step is preferably 100 minutes or more and 500 minutes or less. When the degassing step is performed while continuously or stepwise lowering the pressure in the chamber 10, the degassing time is the time from when the temperature in the crucible 14 reaches a predetermined temperature (150°C or more and 250°C or less) until the pressure in the chamber 10 reaches a predetermined target pressure.

[Vapor deposition process]
In the vapor deposition process, while the workpiece film 20 is transported by a roll-to-roll method, an antifouling layer is formed by vacuum vapor deposition on the main surface 20a of the workpiece film 20 opposite the film-forming roll 12. Specifically, the solidified antifouling agent composition 15 degassed in the degassing process is used as the vapor deposition material, and the vaporized vapor deposition material (antifouling agent) is vapor-deposited on the main surface 20a of the workpiece film 20 to form an antifouling layer as a vapor-deposited film on the main surface 20a.

In order to form an antifouling layer with excellent antifouling properties, the degree of vacuum in the chamber 10 in the vapor deposition step is preferably 9.0×10 ⁻³ Pa or less, and more preferably 8.0×10 ⁻³ Pa or less. There are no particular restrictions on the lower limit of the degree of vacuum in the chamber 10 in the vapor deposition step, but from the viewpoint of reducing production costs, it is preferably 1.0×10 ⁻³ Pa or more. Furthermore, in order to form an antifouling layer with excellent antifouling properties, the water pressure in the chamber 10 in the vapor deposition step is preferably 1 Pa or less.

The heating temperature (deposition temperature) inside the crucible 14 during the deposition process can be set appropriately depending on the type of deposition material. When continuously forming an anti-fouling layer using a roll-to-roll vacuum deposition method, the amount of deposition material inside the crucible 14 gradually decreases from the start of transport (start of deposition) to the end of transport (end of deposition), making it difficult for the deposition material to sublimate. Therefore, in order to maintain a consistent thickness for the continuously formed anti-fouling layer, it is preferable to gradually increase the deposition temperature during the deposition process from the start of transport to the end of transport to promote sublimation of the deposition material.

[Step of removing excess antifouling agent]
The process of removing excess antifouling agent is a process of removing excess antifouling agent (e.g., unfixed antifouling agent) present on the surface of the antifouling layer after the antifouling layer is formed on the workpiece film 20. By removing the excess antifouling agent, it is possible to prevent poor appearance of the film (e.g., cloudiness) caused by the excess antifouling agent. One method of removing excess antifouling agent is to, for example, adhere the adhesive surface of a protective film to the formed antifouling layer, and then peel the protective film from the antifouling layer to adhere the excess to the adhesive surface, thereby removing the excess from the antifouling layer.

[Work film]
Next, an example of the workpiece film 20 will be described. In this embodiment, when an anti-reflection film having an anti-fouling layer is manufactured, a film having an anti-reflection layer is used as the workpiece film 20. Furthermore, when a gas barrier film having an anti-fouling layer is manufactured in this embodiment, a film having a gas barrier layer is used as the workpiece film 20. Furthermore, when a transparent conductive film having an anti-fouling layer is manufactured in this embodiment, a film having a transparent conductive layer is used as the workpiece film 20. The anti-reflection layer, the gas barrier layer, and the transparent conductive layer are all preferably inorganic oxide layers. In other words, a workpiece film having an inorganic oxide layer is preferred as the workpiece film 20. When a workpiece film having an inorganic oxide layer is used as the workpiece film 20, the anti-fouling layer is formed, for example, on one main surface of the inorganic oxide layer. In this case, the anti-fouling layer and the inorganic oxide layer are in contact with each other in the resulting anti-fouling film.

Below, we will explain a film equipped with an anti-reflection layer as an example of a workpiece film 20. Figure 2 is a cross-sectional view of a workpiece film 20 equipped with an anti-reflection layer. The workpiece film 20 shown in Figure 2 is a laminate having a transparent film substrate 101, a hard coat layer 102, a primer layer 103, and an anti-reflection layer 104, in this order. Using the workpiece film 20 shown in Figure 2, an anti-fouling layer 105 (see Figure 3) is formed on the main surface 20a of the workpiece film 20 (the main surface of the anti-reflection layer 104) in the vapor deposition process described above, thereby obtaining the anti-fouling film 100 shown in Figure 3 (an anti-reflection film equipped with the anti-fouling layer 105).

In the antifouling film 100 shown in Figure 3, the antifouling layer 105 is the outermost layer of the antifouling film 100. By providing the antifouling layer 105 as the outermost layer, for example, the effects of contamination from the external environment (fingerprints, hand marks, dust, etc.) can be reduced and contaminants adhering to the surface of the antifouling film 100 can be easily removed.

The anti-reflection layer 104 has four layers, in this order from the primer layer 103 side: high refractive index layer 106, low refractive index layer 107, high refractive index layer 108, and low refractive index layer 109. Details of the high refractive index layer and low refractive index layer will be described later. Note that the anti-reflection layer is not limited to a four-layer structure like anti-reflection layer 104, and may have a two-layer structure, a three-layer structure, a five-layer structure, or a stacked structure of six or more layers. The anti-reflection layer may also have a single-layer structure. The anti-reflection layer is preferably an alternating stack of two or more high refractive index layers and two or more low refractive index layers.

A silicon oxide layer is preferred as the low refractive index layer 109, which is the surface layer on the principal surface 20a side of the anti-reflection layer 104. Because the difference in refractive index between the silicon oxide layer and the anti-fouling layer 105 is relatively small, even if the anti-fouling layer 105 is provided on the silicon oxide layer, a decrease in the anti-reflection performance of the anti-reflection layer 104 can be suppressed. Note that when the low refractive index layer 109 is a silicon oxide layer, the anti-fouling layer 105 is formed on one principal surface (principal surface 20a) of the silicon oxide layer in the vapor deposition process described above.

[Elements of anti-fouling film]
Next, the elements of the antifouling film (specifically, the antireflection film having an antifouling layer) will be described.

(Transparent film substrate)
The transparent film substrate is, for example, a flexible, transparent resin film. Examples of materials constituting the transparent film substrate include polyester resins, polyolefin resins, polystyrene resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, cellulose resins, norbornene resins, polyarylate resins, and polyvinyl alcohol resins. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of cellulose resins include triacetyl cellulose (TAC). These materials may be used alone or in combination of two or more. From the viewpoints of transparency and strength, the material for the transparent film substrate is preferably one selected from the group consisting of polyester resins, polyolefin resins, and cellulose resins, more preferably one selected from the group consisting of PET, COP, and TAC, and even more preferably PET. In other words, as the transparent film substrate, a type of film selected from the group consisting of polyester resin film, polyolefin resin film, and cellulose resin film is preferred, a type of film selected from the group consisting of PET film, COP film, and TAC film is more preferred, and a PET film is even more preferred.

From the viewpoint of strength, the thickness of the transparent film substrate is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From the viewpoint of handleability, the thickness of the transparent film substrate is preferably 300 μm or less, and more preferably 200 μm or less.

One or both main surfaces of the transparent film substrate may be subjected to a surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

To improve the transparency of the anti-fouling film, the total light transmittance (JIS K 7375-2008) of the transparent film substrate is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more and 100% or less.

(Hard Coat Layer)
The hard coat layer is a layer that enhances the mechanical properties of the work film, such as hardness and elastic modulus. The hard coat layer is, for example, composed of a cured product of a curable resin composition (hard coat layer-forming composition). A method for forming the hard coat layer can be employed, for example, by applying the curable resin composition (hard coat layer-forming composition) to a transparent film substrate, and then removing the solvent and curing the resin as necessary. Examples of curable resins contained in the curable resin composition include polyester resins, acrylic resins, urethane resins, urethane acrylate resins, amide resins, silicone resins, epoxy resins, and melamine resins. These curable resins may be used alone or in combination. From the viewpoint of increasing the hardness of the hard coat layer, the curable resin is preferably one or more selected from the group consisting of acrylic resins and urethane acrylate resins, with urethane acrylate resins being more preferred.

Curable resin compositions include, for example, ultraviolet-curable resin compositions and thermosetting resin compositions. From the perspective of improving the productivity of workpiece films, ultraviolet-curable resin compositions are preferred as curable resin compositions. UV-curable resin compositions include one or more components selected from the group consisting of ultraviolet-curable monomers, ultraviolet-curable oligomers, and ultraviolet-curable polymers. Specific examples of ultraviolet-curable resin compositions include the hard coat layer-forming composition described in JP 2016-179686 A.

The curable resin composition may also contain particles having a number-average primary particle diameter of 0.5 μm or more (hereinafter, sometimes referred to as "microparticles"). In other words, the hard coat layer may contain microparticles. By incorporating microparticles into the curable resin composition, it is possible to adjust the hardness, surface roughness, refractive index, and anti-glare properties of the hard coat layer. Examples of microparticles include metal (or semi-metal) oxide particles, glass particles, and organic particles. Examples of materials for metal (or semi-metal) oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for organic particles include polymethyl methacrylate, polystyrene, polyurethane, (meth)acrylate compound-styrene copolymer, benzoguanamine, melamine, polymethylsilsesquioxane, and polycarbonate.

To easily adjust the anti-glare properties of the hard coat layer, the number-average primary particle diameter of the microparticles is preferably 1.0 μm or more and 5.0 μm or less, and more preferably 2.0 μm or more and 4.0 μm or less.

To easily adjust the antiglare properties of the hard coat layer, the amount of microparticles in the hard coat layer is preferably 5 parts by weight or more, and may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more, per 100 parts by weight of curable resin. The upper limit of the amount of microparticles in the hard coat layer is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, per 100 parts by weight of curable resin.

The curable resin composition may also contain particles having a number-average primary particle diameter of less than 0.5 μm (hereinafter, sometimes referred to as "nanoparticles"). When the hard coat layer is made from a cured product of a curable resin composition containing nanoparticles, fine irregularities are formed on the surface of the hard coat layer, which tends to improve adhesion between the hard coat layer and layers formed thereon.

From the perspective of forming a fine uneven shape that contributes to improved adhesion, the number average primary particle diameter of the nanoparticles is preferably 20 nm or more and 80 nm or less, more preferably 25 nm or more and 70 nm or less, and even more preferably 30 nm or more and 60 nm or less.

Inorganic oxides are preferred as nanoparticle materials. Examples of inorganic oxides include metal (or semi-metal) oxides such as silicon oxide (silica), titanium oxide, aluminum oxide, zirconium oxide, niobium oxide, zinc oxide, tin oxide, cerium oxide, and magnesium oxide. The inorganic oxide may also be a composite oxide of multiple (semi-)metals. Among the inorganic oxides listed above, silicon oxide is preferred due to its high adhesion-enhancing effect. In other words, silicon oxide particles (silica particles) are preferred as nanoparticles. Functional groups such as acrylic groups and epoxy groups may be introduced onto the surfaces of inorganic oxide nanoparticles to enhance adhesion and affinity with resins.

The amount of nanoparticles in the hard coat layer is preferably 5 parts by weight or more, and may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more, per 100 parts by weight of curable resin. If the amount of nanoparticles is 5 parts by weight or more, adhesion to the layer formed on the hard coat layer can be further improved. The upper limit of the amount of nanoparticles in the hard coat layer is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, per 100 parts by weight of curable resin.

The curable resin composition (hard coat layer-forming composition) contains, for example, the curable resin described above and a polymerization initiator (e.g., a photopolymerization initiator), and optionally a solvent capable of dissolving or dispersing these components. In addition to the above components, the curable resin composition (hard coat layer-forming composition) may also contain additives such as microparticles, nanoparticles, leveling agents, viscosity modifiers (thixotropic agents, thickeners, etc.), antistatic agents, antiblocking agents, dispersants, dispersion stabilizers, antioxidants, UV absorbers, antifoaming agents, surfactants, and lubricants.

From the viewpoint of increasing the hardness of the hard coat layer, the thickness of the hard coat layer is preferably 1 μm or more, more preferably 2 μm or more. From the viewpoint of ensuring the flexibility of the antifouling film, the thickness of the hard coat layer is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and even more preferably 30 μm or less.

The main surface of the hard coat layer opposite the transparent film substrate may be subjected to a surface modification treatment. Examples of surface modification treatments include plasma treatment, corona treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

(Primer layer)
In order to improve the adhesion between the hard coat layer and the anti-reflection layer, it is preferable to provide a primer layer between the hard coat layer and the anti-reflection layer.The material of the primer layer includes metals (or semi-metals) such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, indium, tungsten, aluminum, zirconium, palladium, etc.; alloys of these metals (or semi-metals); oxides, fluorides, sulfides, or nitrides of these metals (or semi-metals).The oxide constituting the primer layer may be a composite oxide such as indium tin oxide (ITO).Among these, inorganic oxides are preferred as the material of the primer layer, with silicon oxide, indium oxide, or ITO being more preferred, and ITO being even more preferred.

To ensure the light transmittance of the primer layer while improving the adhesion between the hard coat layer and the anti-reflection layer, the thickness of the primer layer is preferably 0.5 nm or more and 20 nm or less, more preferably 0.5 nm or more and 10 nm or less, and even more preferably 1.0 nm or more and 10 nm or less.

The method for forming the primer layer is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred, as they allow for the formation of a thin film with a uniform thickness. Furthermore, from the perspective of improving productivity, a method in which the primer layer is formed using a roll-to-roll sputtering deposition device (roll-to-roll sputtering method) is preferred.

In roll-to-roll sputtering, a long film (e.g., a transparent film substrate with a hard coat layer formed thereon) is transported in the longitudinal direction (MD) while continuously depositing, for example, a primer layer and an anti-reflection layer. In sputtering, an inert gas such as argon, and optionally a reactive gas such as oxygen, are introduced into the deposition chamber during deposition. When depositing an oxide layer as a primer layer, sputtering can be performed using either an oxide target or reactive sputtering using a metal (or semi-metal) target. Examples of power sources for performing sputtering include DC power sources, AC power sources, RF power sources, and MFAC power sources (AC power sources with a frequency range of several kHz to several MHz).

(Anti-reflection layer)
The antireflection layer preferably comprises two or more thin films with different refractive indices. Generally, the optical film thickness (product of refractive index and thickness) of the thin films of the antireflection layer is adjusted so that the reversed phases of incident light and reflected light cancel each other out. By forming the antireflection layer as a multilayer laminate of two or more thin films with different refractive indices, the reflectance can be reduced over a wide wavelength range of visible light.

Examples of thin film materials that make up the anti-reflection layer include metal (or semi-metal) oxides, nitrides, and fluorides. The anti-reflection layer is preferably an alternating laminate of high-refractive index layers and low-refractive index layers.

The high-refractive index layer has a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of materials for the high-refractive index layer include titanium oxide, niobium oxide (e.g., Nb ₂ O ₅ ), zirconium oxide, tantalum oxide, zinc oxide, indium oxide, ITO, and antimony-doped tin oxide (ATO). Among these, at least one material selected from the group consisting of titanium oxide and niobium oxide is preferred. The low-refractive index layer has a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of materials for the low-refractive index layer include silicon oxide (e.g., SiO ₂ ), titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among these, silicon oxide is preferred. It is particularly preferred to alternately stack niobium oxide thin films as the high-refractive index layer and silicon oxide thin films as the low-refractive index layer. In addition to the low-refractive index layer and the high-refractive index layer, a medium-refractive index layer having a refractive index greater than 1.6 and less than 1.9 may be provided.

The film thickness of each of the high refractive index layer and the low refractive index layer is preferably 5 nm or more and 200 nm or less, and more preferably 10 nm or more and 150 nm or less. The film thickness of each layer can be designed to reduce the reflectance of visible light depending on the refractive index, layer structure, etc.

When the anti-reflection layer is a four-layer alternating laminate consisting of niobium oxide thin films as high-refractive index layers and silicon oxide thin films as low-refractive index layers, the anti-reflection layer may be configured to have, from the hard coat layer side, a niobium oxide thin film with a thickness of 5 nm to 20 nm, a silicon oxide thin film with a thickness of 10 nm to 40 nm, a niobium oxide thin film with a thickness of 65 nm to 120 nm, and a silicon oxide thin film with a thickness of 60 nm to 100 nm, in that order.

To obtain an antifouling film with excellent flex resistance, the thickness of the antireflection layer is preferably 140 nm or more and 280 nm or less, more preferably 170 nm or more and 280 nm or less, even more preferably 180 nm or more and 260 nm or less, and even more preferably 190 nm or more and 250 nm or less. In this specification, the "thickness of the antireflection layer" refers to the sum (total thickness) of the thicknesses of the individual layers that make up the antireflection layer.

The method for forming the anti-reflection layer is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred, as they allow for the formation of a thin film with a uniform thickness. Furthermore, from the perspective of improving productivity, a method in which the anti-reflection layer is formed using a roll-to-roll sputtering film-forming device (roll-to-roll sputtering method) is preferred.

When depositing an oxide layer as an anti-reflection layer, the oxide layer can be deposited by sputtering using either an oxide target or reactive sputtering using a metal (or semi-metal) target. Examples of power sources for sputtering include DC power sources, AC power sources, RF power sources, and MFAC power sources (AC power sources with a frequency range of several kHz to several MHz).

(Anti-fouling layer)
The thickness of the antifouling layer is, for example, 2 nm or more and 50 nm or less. The thicker the antifouling layer, the more improved the antifouling properties tend to be. The thickness of the antifouling layer is preferably 5 nm or more, more preferably 6 nm or more, and even more preferably 7 nm or more. On the other hand, in order to suppress reflection of external light, the thickness of the antifouling layer is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less. In this specification, the "thickness of the antifouling layer" refers to the thickness measured with a quartz crystal resonator film thickness monitor installed in a vacuum deposition apparatus, or the thickness measured with a film thickness monitor using a pipe internal pressure sensor.

To suppress reflection of external light, the maximum height Rz of the main surface of the antifouling layer opposite the antireflection layer side (hereinafter sometimes simply referred to as the "antifouling layer surface") is preferably 0.40 μm or more, more preferably 0.45 μm or more, and even more preferably 0.50 μm or more. To suppress the occurrence of discharge marks, the maximum height Rz of the antifouling layer surface is preferably 1.50 μm or less, more preferably 1.40 μm or less, even more preferably 1.30 μm or less, and even more preferably 1.20 μm or less. Note that "discharge marks" refer to defects caused by electrostatic discharge that occurs between the antifouling layer surface and the charged fingers of the user, etc.

The above describes one example of an antifouling film obtained by the manufacturing method of this embodiment, but the antifouling film obtained by the manufacturing method of this embodiment is not limited to the above example. For example, the antifouling film obtained by the manufacturing method of this embodiment may be an antifouling film that does not include an inorganic oxide layer.

[Preferred embodiment of the method for producing an antifouling film]
In order to increase productivity while further suppressing a decrease in yield when forming the antifouling layer, the method for producing an antifouling film according to this embodiment preferably satisfies the following condition 1, more preferably satisfies the following condition 2, and even more preferably satisfies the following condition 3.
Condition 1: In the degassing step, the atmosphere surrounding the antifouling composition is reduced in pressure to a pressure of 5 Pa or more and 40 Pa or less.
Condition 2: The above condition 1 is satisfied, and an evacuation step is further provided before the degassing step.
Condition 3: The above condition 2 is satisfied, and in the evacuation step, the atmosphere surrounding the antifouling agent composition is reduced in pressure to a pressure of 20 Pa or more and 40 Pa or less.

The following describes examples of the present invention, but the present invention is not limited to the following examples.

<Preparation of antifouling film of Example 1>
[Hard Coat Layer Forming Step]
100 parts by weight (solids equivalent) of a solution of ultraviolet-curable resin mainly composed of urethane acrylate (DIC Corporation "UNIDIC 17-806", solids concentration: 80 wt%), 5 parts by weight of a photopolymerization initiator (BASF Corporation "IRGACURE 906"), and 0.01 parts by weight of a leveling agent (DIC Corporation "GRANDIC PC4100") were mixed. The resulting mixture was diluted with a mixed solvent of cyclopentanone (CPN) and propylene glycol monomethyl ether (PGM) (weight ratio: CPN / PGM = 45 / 55) to prepare a hard coat layer-forming composition with a solids concentration of 36 wt%. Next, the hard coat layer-forming composition was applied to one main surface of a PET film (thickness: 50 μm) as a transparent film substrate, and a coating film was formed. Next, the coating film was dried by heating at a temperature of 90°C for 60 seconds, and then cured by ultraviolet irradiation. When irradiating ultraviolet light, a high-pressure mercury lamp was used as the light source, ultraviolet light with a wavelength of 365 nm was used, and the integrated light amount was set to 300 mJ/ ^cm2 . In this way, a hard coat layer with a thickness of 5 µm was formed on the PET film.

[Surface treatment step of hard coat layer]
Next, the surface of the hard coat layer was plasma-treated using a roll-to-roll plasma treatment device while transporting the PET film on which the hard coat layer was formed in a vacuum atmosphere at a pressure of 1.0 Pa. During the plasma treatment, argon gas was used as the inert gas, and the discharge power was set to 780 W. This resulted in a laminate (hereinafter, sometimes referred to as "optical film F1") comprising the PET film and the plasma-treated hard coat layer.

[Primer layer formation process]
The optical film F1 obtained by the above procedure was introduced into a roll-to-roll sputtering deposition apparatus, and the pressure inside the deposition chamber was reduced to 1×10 ⁻⁴ Pa. Next, while the optical film F1 was being transported, a 1.5 nm thick ITO layer was formed (deposited) as a primer layer on one main surface of the hard coat layer by a reactive sputtering method. To form the primer layer, an ITO target containing indium oxide and tin oxide in a weight ratio of 90:10 was used as the target material. In addition, when depositing by the reactive sputtering method, the power source was an MFAC power source (frequency: 40 kHz), and 100 parts by volume of argon gas and 10 parts by volume of oxygen gas were used as inert gases, the discharge voltage was 400 V, and the pressure inside the deposition chamber was 0.2 Pa.

[Anti-reflection layer forming process]
Following the formation of the primer layer, a roll-to-roll sputtering deposition apparatus was used to transport the optical film F1 after the primer layer formation. The following layers were then deposited on one major surface of the primer layer by reactive sputtering: a first layer: a 12 nm thick niobium oxide layer (refractive index: 2.33), a second layer: a 28 nm thick silicon oxide layer (refractive index: 1.46), a third layer: a 100 nm thick niobium oxide layer, and a fourth layer: an 85 nm thick silicon oxide layer, in this order. This resulted in a four-layer anti-reflection layer (composed of first, second, third, and fourth layers) on one major surface of the primer layer, resulting in a workpiece film having a PET film, a hard coat layer, a primer layer, and an anti-reflection layer, in this order. Note that the power source for each of the first through fourth layers was an MFAC power supply (frequency: 40 kHz). In addition, in the formation of the first layer, a Nb target was used, 100 parts by volume of argon gas and 5 parts by volume of oxygen gas were used, the discharge voltage was 415 V, and the pressure in the film formation chamber was 0.42 Pa. In the formation of the second layer, a Si target was used, 100 parts by volume of argon gas and 30 parts by volume of oxygen gas were used, the discharge voltage was 350 V, and the pressure in the film formation chamber was 0.3 Pa. In the formation of the third layer, a Nb target was used, 100 parts by volume of argon gas and 13 parts by volume of oxygen gas were used, the discharge voltage was 460 V, and the pressure in the film formation chamber was 0.5 Pa. In the formation of the fourth layer, a Si target was used, 100 parts by volume of argon gas and 30 parts by volume of oxygen gas were used, the discharge voltage was 340 V, and the pressure in the film formation chamber was 0.25 Pa.

Next, the following evacuation process, degassing process, and vapor deposition process were carried out in this order to form an anti-fouling layer on the surface of the anti-reflection layer.

[Exhaust process]
First, a coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient concentration: 20 wt%) was prepared as an antifouling composition. The active ingredient (antifouling agent) of the coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd.) used was an alkoxysilane compound (fluorine-containing compound) containing a perfluoropolyether skeleton. The solvent contained in the coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd.) used was hydrofluoroether. 500 g of this coating agent was placed in a crucible placed in the chamber of a roll-to-roll vacuum deposition apparatus. Next, while maintaining the atmosphere in the chamber at a temperature of 23°C, the pressure was reduced from normal pressure to a pressure of 30 Pa using a vacuum pump, and the chamber was evacuated.

[Degassing process]
Next, the heating mechanism provided in the crucible was activated to raise the temperature inside the crucible to 150°C, and the atmosphere inside the chamber was decompressed using a vacuum pump. The degassing process was completed when the pressure inside the chamber reached 30 Pa. The degassing time (the time from when the temperature inside the crucible reached 150°C until the pressure inside the chamber reached 30 Pa) was 480 minutes.

[Vapor deposition process]
Next, using the roll-to-roll vacuum deposition apparatus, a 12 nm thick antifouling layer was formed by vacuum deposition on the surface of the antireflection layer of the workpiece film (specifically, on the main surface opposite the primer layer of the antireflection layer) while the workpiece film was being transported. Specifically, the vacuum level in the chamber was set to 8.0 × 10 ^-3 Pa, and the temperature in the crucible was raised to 195°C. Then, the workpiece film was transported. The degassed solidified coating agent in the crucible was used as the deposition material to continuously form an antifouling layer on the surface of the antireflection layer of the workpiece film. During the continuous formation of the antifouling layer, the heating temperature (deposition temperature) in the crucible was controlled using a proportional-integral-differential controller (PID) to maintain the target antifouling layer thickness (12 nm). The deposition temperature gradually increased from the start to the end of the workpiece film transport, and the deposition temperature at the end of the transport (end of the deposition process) was 300°C.

[Step of removing excess antifouling agent]
Next, a protective film ("RP300C" manufactured by Nitto Denko Corporation) was laminated onto the formed antifouling layer, and the film was left for 24 hours. The protective film was then peeled off from the antifouling layer to remove excess fluorine-containing compound present on the surface of the antifouling layer. Through the above procedure, the antifouling film of Example 1 (a roll of antireflection film having a length of 1000 m and a width of 1330 mm) was obtained.

<Preparation of antifouling film of Comparative Example 1>
An antifouling film of Comparative Example 1 was obtained by the same production method as in Example 1, except that the heating temperature inside the crucible was changed to 100°C in the degassing step.

<Evaluation method>
The following describes the methods for evaluating the antifouling films of Example 1 and Comparative Example 1. For each evaluation item, samples were taken from the locations on each antifouling film where the antifouling layer was formed when the deposition temperatures were 195°C, 200°C, 205°C, 210°C, 250°C, and 300°C (six locations in total for each antifouling film), and these samples were used as evaluation samples.

[Water contact angle]
Using a contact angle measuring device ("DMo-501" manufactured by Kyowa Interface Science Co., Ltd.), 1 μL of water was dropped onto the antifouling layer surface of the evaluation sample (the main surface of the antifouling layer opposite the antireflection layer side), and 2 seconds after the drop, the angle between the antifouling layer surface and the tangent line of the droplet edge was measured. When the water contact angle was 110° or more, the sample was evaluated as having "excellent antifouling properties." On the other hand, when the water contact angle was less than 110°, the sample was evaluated as having "poor antifouling properties."

[Sliding resistance]
An eraser sliding test was carried out on the antifouling layer surface of the evaluation sample under the following conditions, and then the water contact angle of the antifouling layer surface was measured using the method described in the above section [Water Contact Angle]. In the eraser sliding test, a Minoan eraser (6 mmφ) was used, the eraser load on the antifouling layer surface was 1 kg/6 mmφ, the sliding distance of the eraser on the antifouling layer surface (one way in reciprocating motion) was 20 mm, the sliding speed of the eraser was 40 reciprocating motions/min, and the number of reciprocating motions of the eraser on the antifouling layer surface was 3,000. If the water contact angle after the eraser sliding test was 100° or more, it was evaluated as A (excellent sliding resistance). On the other hand, if the water contact angle after the eraser sliding test was less than 100°, it was evaluated as B (not excellent sliding resistance).

[Dynamic friction coefficient]
Using an automatic friction and wear analyzer ("TSf-503" manufactured by Kyowa Interface Science Co., Ltd.), the surface of the antifouling layer of the evaluation sample was rubbed in one direction using a 10 mmφ felt as a sliding piece under conditions of a load of 500 g, a sliding distance of 50 mm, and a speed of 1.67 mm/min, and the average value of the obtained friction coefficients (friction force/load) was taken as the dynamic friction coefficient of the antifouling layer. If the dynamic friction coefficient was 0.160 or less, it was evaluated as having "excellent abrasion resistance." On the other hand, if the dynamic friction coefficient exceeded 0.160, it was evaluated as having "poor abrasion resistance."

<Evaluation results>
Table 1 shows the evaluation results of the water contact angle, sliding resistance, and dynamic friction coefficient for Example 1 and Comparative Example 1.

In Example 1, the heating temperature in the degassing process was 150°C. As shown in Table 1, in Example 1, the water contact angle was 110° or greater at all deposition temperatures from 195°C to 300°C. Therefore, the antifouling film of Example 1 had excellent antifouling properties throughout the entire longitudinal direction. In Example 1, the sliding resistance was A at all deposition temperatures from 195°C to 300°C. Therefore, the antifouling film of Example 1 had excellent sliding resistance throughout the entire longitudinal direction. In Example 1, the dynamic friction coefficient was 0.160 or less at all deposition temperatures from 195°C to 300°C. Therefore, the antifouling film of Example 1 had excellent abrasion resistance throughout the entire longitudinal direction.

In Comparative Example 1, the heating temperature in the degassing process was 100°C. As shown in Table 1, in Comparative Example 1, the water contact angle at the locations where the antifouling layer was formed at deposition temperatures of 195°C and 200°C was less than 110°. Therefore, some of the antifouling film in Comparative Example 1 did not have excellent antifouling properties. In Comparative Example 1, the sliding resistance at the locations where the antifouling layer was formed at deposition temperatures of 195°C and 200°C was rated B. Therefore, some of the antifouling film in Comparative Example 1 did not have excellent sliding resistance. In Comparative Example 1, the dynamic friction coefficient at the locations where the antifouling layer was formed at deposition temperatures of 195°C and 200°C exceeded 0.160. Therefore, some of the antifouling film in Comparative Example 1 did not have excellent abrasion resistance.

Furthermore, the yield rates (unit: %) for Example 1 and Comparative Example 1 were calculated using the following formula, and the result was that the yield rate for Example 1 was 10% higher than the yield rate for Comparative Example 1. In the following formula, the "length of the portion where antifouling properties are ensured" means the length (unit: m) of the portion where the water contact angle is 110° or more, the sliding resistance is A, and the dynamic friction coefficient is 0.160 or less. In the following formula, the "total length" is 1000 m.
Yield rate = 100 x length of area where antifouling properties are ensured / total length

These results demonstrate that the present invention can suppress a decrease in yield when forming an anti-fouling layer using a roll-to-roll vacuum deposition method.

15: Antifouling agent composition 20: Work film 100: Antifouling film 105: Antifouling layer

Claims (7)

A method for manufacturing an antifouling film, comprising: conveying a workpiece film having a base material of a resin film by a roll-to-roll method; and forming an antifouling layer on one main surface of the workpiece film by a vacuum deposition method;
a step Sa of degassing an antifouling composition containing a fluorine-based solvent under a reduced pressure atmosphere at a temperature of 150° C. or higher and 250° C. or lower before forming the antifouling layer;
the antifouling composition contains a fluorine-containing compound as an antifouling agent,
The antifouling layer is formed using the antifouling agent composition degassed in the step Sa as a deposition material. The method for producing an antifouling film according to claim 1 , wherein the fluorine-containing compound is an alkoxysilane compound containing a perfluoropolyether skeleton. The workpiece film includes an inorganic oxide layer,
The method for producing an antifouling film according to claim 1 , wherein the antifouling layer is formed on one main surface of the inorganic oxide layer. the inorganic oxide layer includes a silicon oxide layer,
The method for producing an antifouling film according to claim 3 , wherein the antifouling layer is formed on one main surface of the silicon oxide layer. The method for producing an antifouling film according to claim 1, wherein the degree of vacuum when the antifouling layer is formed is 9.0×10 ⁻³ Pa or less. The method for producing an antifouling film according to claim 1, wherein in step Sa, degassing is performed under a reduced pressure atmosphere of 40 Pa or less. The method for producing an antifouling film according to claim 1, further comprising, prior to step Sa, a step of reducing the pressure of the atmosphere surrounding the antifouling composition at a temperature of 30°C or less.