Article having coating, method for producing the same, and composition for forming iron oxide coating

Abstract

To provide a coating-forming composition capable of efficiently forming an iron oxide coating.SOLUTION: A composition for forming an iron oxide coating containing a specific β-diketone metal compound and an aromatic electron-donating organic solvent is provided, wherein the aromatic electron-donating organic solvent is preferably anisole, and the iron oxide coating is preferably an amorphous iron(III) oxide coating.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an article having a coating, a method for producing the same, and a composition for forming an iron oxide coating. [Background technology]

[0002] Inorganic coatings are used in a wide range of fields because they can be formed into high-value-added thin films using a variety of methods. In particular, light-shielding coatings that utilize optical properties are currently attracting attention from the perspectives of transparency and heat resistance. For example, Patent Document 1 discloses a glass container whose outer surface is coated with a zinc oxide coating, thereby achieving high visible light transmittance and ultraviolet light blocking function (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-147695 Summary of the Invention [Problem to be solved by the invention]

[0004] Glass containers with reduced UV transmittance are useful in a wide range of industries, including pharmaceuticals, cosmetics, and food. For example, in the case of containers containing pharmaceuticals, low UV transmittance is desirable because light degradation of the contained pharmaceuticals can result in insufficient efficacy. Furthermore, containers containing biopharmaceuticals, such as antibody drugs, which have attracted attention in recent years, are required to be able to block high-energy visible light (HEV) up to approximately 450 nm (see I. Prajapati, et al. Mol. Pharmaceutics 2021, 18, 3223-3234). For various applications, such as those mentioned above, there is a demand for coatings that can block UV rays and also block short-wavelength visible light (high-energy visible light), which has the second highest energy after UV rays, and thus can block light over a wide wavelength range.

[0005] For example, Patent Document 1 discloses a glass container that can reduce the deterioration of pharmaceuticals due to ultraviolet rays by coating the glass container with a zinc oxide film. However, with regard to the light-blocking function of the zinc oxide film, it is theoretically difficult for the band gap derived from zinc oxide to block light rays of 380 nm or more.

[0006] On the other hand, glass containers used for various purposes are required to have high transmittance (transparency) in the visible light wavelength range, which is not related to deterioration of the contents, in order to ensure internal visibility and allow the use of foreign matter inspection equipment. Brown glass bottles, which are general-purpose light-blocking containers, have a maximum transmittance at wavelengths around 360 nm, transmit some light between 300 nm and 500 nm, and primarily transmit light above 500 nm. However, brown glass bottles do not have sufficient transmittance in the ultraviolet range, and their transmittance for light in the long wavelength range above 500 nm is also low (see Japan Society of Nutrition and Food Science, Vol. 28, No. 5 (1975) pp. 257-261).

[0007] In view of the above, one aspect of the present invention aims to provide an article having a glass substrate and a coating that can block light rays in a wide wavelength range (ultraviolet rays and high-energy visible light) and has high transparency.

[0008] In the course of their investigations, the inventors have focused on iron oxide coatings, and as a result of further intensive investigations, they have newly discovered that the iron oxide coatings described in detail below can block light in a wide wavelength range (ultraviolet rays and high-energy visible light) and have high transparency.

[0009] Another aspect of the present invention is to provide a composition for forming a coating that enables efficient formation of an iron oxide coating. For example, when comparing coating compositions with the same applied amount, efficient coating formation can be defined as a coating that allows the formation of a thicker coating.

[0010] As a result of extensive research, the present inventors have newly discovered that efficient formation of an iron oxide film is possible by using an aromatic electron-donating organic solvent as the solvent in a film-forming composition containing a β-diketone metal compound, as described in detail below, as a precursor of iron oxide. [Means for solving the problem]

[0011] One aspect of the present invention is as follows. [1] A glass substrate and an amorphous iron (III) oxide coating, The article has an arithmetic mean roughness Ra of the surface of the coating opposite to the glass substrate side of 100 nm or more and 250 nm or less. [2] The article according to [1], wherein the coating has a thickness of 250 nm or more and 650 nm or less. [3] The article according to [1] or [2], wherein the coating satisfies all of the following (1) to (3): (1) The average transmittance in the wavelength range of 600 nm or more and 800 nm or less is 70.0% or more. (2) The transmittance at a wavelength of 450 nm is 20.0% or less. (3) The transmittance at a wavelength of 360 nm is 5.0% or less. [4] The glass substrate is a glass container, and The article according to any one of [1] to [3], wherein the coating is a coating that covers at least a part of the outer surface of the glass container. [5] The thickness of the coating is 250 nm or more and 650 nm or less, The coating satisfies all of the following (1) to (3): The glass substrate is a glass container; and The article according to any one of [1] to [4], wherein the coating is a coating that covers at least a part of the outer surface of the glass container. (1) The average transmittance in the wavelength range of 600 nm or more and 800 nm or less is 70.0% or more. (2) The transmittance at a wavelength of 450 nm is 20.0% or less. (3) The transmittance at a wavelength of 360 nm is 5.0% or less. [6] A method for producing the article according to any one of [1] to [5], Formula 1 below: [ka] (In formula 1, R 1 and R 2 each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. The above-mentioned production method includes forming the coating by applying a composition (also referred to as a "coating composition") containing a β-diketone metal compound represented by the following formula (1) onto a glass substrate. [7] The manufacturing method according to [6], in which the coating film has a thickness of 250 nm or more and 650 nm or less. [8] The method according to [6] or [7], wherein the composition further contains an electron-donating organic solvent.

[0012] Another aspect of the present invention is as follows. [1] Formula 1 below: [ka] (In formula 1, R 1 and R 2 each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. a β-diketone metal compound represented by the formula: an aromatic electron donating organic solvent; A composition for forming an iron oxide film, comprising: [2] The composition for forming an iron oxide film according to [1], wherein the aromatic electron-donating organic solvent is anisole. [3] The composition for forming an iron oxide film according to [1], wherein the iron oxide film is an amorphous iron (III) oxide film. [4] The composition for forming an iron oxide film according to [2], wherein the iron oxide film is an amorphous iron (III) oxide film. [5] A method for producing an article having a glass substrate and an amorphous iron (III) oxide coating, comprising: The method for producing the amorphous iron (III) oxide film comprises applying the composition for forming an iron oxide film according to [3] or [4] onto a glass substrate to form the amorphous iron (III) oxide film. [6] The manufacturing method according to [5], in which the coating film has a thickness of 250 nm or more and 650 nm or less. [Effects of the Invention]

[0013] According to one aspect of the present invention, it is possible to provide an article having a highly transparent coating on a glass substrate that can block light rays in a wide wavelength range (ultraviolet rays and high-energy visible light), and a method for manufacturing the same. Furthermore, according to one aspect of the present invention, it is possible to provide a composition for forming an iron oxide film, which can enable efficient formation of an iron oxide film. DETAILED DESCRIPTION OF THE INVENTION

[0014] One aspect of the present invention relates to an article having a glass substrate and an amorphous iron(III) oxide coating, wherein the arithmetic mean roughness Ra of the surface of the coating opposite the glass substrate is 100 nm or more and 250 nm or less. As a result of extensive research by the inventors, it has been discovered that the coating can block light rays in a wide wavelength range (ultraviolet rays and high-energy visible light) and exhibit high transparency. By providing the coating on an article having a glass substrate, it is possible to impart the light-blocking performance desired for various applications to the article without significantly reducing transparency. The above article will now be described in more detail.

[0015] [Coating] The coating of the above-mentioned article is an amorphous iron(III) oxide coating. In the present invention and this specification, the term "amorphous iron(III) oxide coating" refers to a coating containing amorphous iron(III) oxide. The iron oxide contained in such a coating is iron(III) oxide and exhibits amorphous properties.

[0016] "Amorphousness" is evaluated based on the diffraction pattern of known XRD (X-ray diffraction) data. In the case of α-iron(III) oxide, it is known that there are diffraction peaks at 2θ of approximately 24°, 33°, 35°, and 41°. If the maximum relative intensity at one or more of these points is greater than the relative intensity of the baseline, it can be said to be crystalline (i.e., not amorphous). θ is the Bragg angle, and 2θ is the diffraction angle. deg is an abbreviation for degrees. The baseline relative intensity can be any angle where no diffraction pattern is present, for example, there are no known diffraction peaks for α-iron(III) oxide around 28° 2θ. In addition, in the case of broad peaks, it is assumed that the relative intensity ratio at a single point does not accurately reflect the diffraction pattern. Taking this into consideration, the average relative intensity within a range of ±0.5° from the reference angle is compared with the baseline relative intensity. In consideration of the above, the term "amorphous" in the amorphous iron(III) oxide of the present invention and this specification is defined as follows. In the XRD data of the film to be measured, if one or more of the maximum relative intensities within a range of ±0.5 degrees at 2θ of 24 degrees, 33 degrees, 35 degrees, and 41 degrees is less than 2.00 times the relative intensity at 2θ of 28 degrees (relative intensity of the baseline), the film is evaluated as "amorphous."

[0017] Amorphous coatings are believed to exhibit different optical properties than crystalline coatings. For example, it is believed that crystalline coatings tend to have lower visible light transmittance than amorphous coatings due to the presence of crystal grain agglomerates. Therefore, the inventors believe that the fact that the coating of the above-mentioned article is an amorphous coating can contribute to the coating's high transparency. The inventors also believe that amorphous coatings are preferable because they tend to have higher mechanical strength than crystalline coatings.

[0018] Furthermore, it can be confirmed by XPS (X-ray Photoelectron Spectroscopy) analysis that the iron oxide contained in the coating is iron(III) oxide. Three types of iron oxide are commonly known: FeO (wustite), Fe2O3 (hematite), and Fe3O4 (maghemite), with band gaps of approximately 2.5-4.0 eV, 2.0-2.2 eV, and 0.1 eV, respectively. The photon energy (units of electron volts) calculated from the Fe2O3 (hematite) band gap is approximately 550 nm, so from a band gap theory perspective, it is considered suitable for blocking ultraviolet rays and high-energy visible light.

[0019] The arithmetic mean roughness Ra of the surface of the amorphous iron (III) oxide coating opposite to the glass substrate side is 100 nm or more and 250 nm or less. In the present invention and this specification, the arithmetic mean roughness Ra of the surface to be measured is the arithmetic mean height Ra of the roughness curve defined in JIS (Japanese Industrial Standards) B 0601: 2013. When the value of Ra displayed on the measuring device includes a decimal point, the value obtained by rounding off the decimal point (i.e., the integer) shall be adopted as the arithmetic mean roughness Ra of the surface to be measured. The surface roughness of a coating has a significant effect on light scattering. It is believed that light scattering is more likely to occur with short-wavelength light (i.e., high-energy light). Therefore, an Ra of 100 nm or more for the amorphous iron (III) oxide coating can contribute to the amorphous iron (III) oxide coating exhibiting excellent light-blocking performance against high-energy visible light. From this perspective, the Ra is preferably 110 nm or more, with 120 nm or more, 130 nm or more, 140 nm or more, and 150 nm or more being more preferred in that order. On the other hand, the Ra of the amorphous iron (III) oxide coating film being 250 nm or less can contribute to the coating film exhibiting high transparency. From this point of view, the Ra is preferably 240 nm or less, and more preferably 230 nm or less, 220 nm or less, 210 nm or less, and 200 nm or less in that order.

[0020] According to the inventors' investigations, the Ra of the amorphous iron (III) oxide coating can be affected by the coating formation method and coating thickness. Increasing the coating thickness can lead to a higher Ra value on the coating surface. From the viewpoint of controlling the Ra to 100 nm or more, the thickness of the amorphous iron (III) oxide coating is preferably 250 nm or more, with 260 nm or more, 270 nm or more, 280 nm or more, 290 nm or more, and 300 nm or more being more preferred in this order. On the other hand, from the viewpoint of controlling the Ra to 250 nm or less, the thickness of the amorphous iron (III) oxide coating is preferably 650 nm or less, with 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, and 400 nm or less being more preferred in this order. The film thickness can be measured using a stylus surface profiler, an example of which is the measuring device described in the Examples section below.

[0021] Regarding optical properties, the amorphous iron(III) oxide coating preferably satisfies one or more of the following (1) to (3), more preferably two or more, and even more preferably all of (1) to (3). The average transmittance (1) and the transmittances (2) and (3) of the amorphous iron(III) oxide coating can be measured using a commercially available spectrophotometer. The transmittance is measured by irradiating light onto the surface to be measured for Ra described above, which serves as the incident surface.

[0022] (1) The average transmittance in the wavelength range of 600 nm to 800 nm is 70.0% or more. The average transmittance is preferably 72.0% or more, and more preferably 74.0% or more. The average transmittance may be, for example, 90.0% or less, 85.0% or less, or 80.0% or less. Since a higher average transmittance indicates higher transparency and is preferable, the average transmittance may exceed the values ​​exemplified here.

[0023] (2) The transmittance at a wavelength of 450 nm is 20.0% or less. The transmittance at a wavelength of 450 nm is preferably 18.0% or less, more preferably 15.0% or less, and even more preferably 10.0% or less. The transmittance at a wavelength of 450 nm is, for example, 0.0% or more, more than 0.0%, or 0.1% or more. It can be 1.0% or more, 2.0% or more, or 3.0% or more. The lower the transmittance at the measured wavelength, the better the function of blocking light at that measured wavelength. The lower the transmittance at a wavelength of 450 nm, the better the ability to block high-energy visible light.

[0024] (3) The transmittance at a wavelength of 360 nm is 5.0% or less. The transmittance at a wavelength of 360 nm is preferably 4.0% or less, and more preferably 3.0% or less, 2.0% or less, 1.0% or less, and 0.5% or less in that order. The transmittance at a wavelength of 360 nm can be 0.0% or more, or can be 0.0%. The lower the transmittance at a wavelength of 360 nm, the more excellent the ability to block ultraviolet rays.

[0025] Furthermore, the transparency of a coating can also be measured by its transmittance at a wavelength of 600 nm. The higher the transmittance at a wavelength of 600 nm, the higher the transparency. The transmittance of the amorphous iron (III) oxide coating at a wavelength of 600 nm is preferably 50.0% or higher, with 55.0% or higher and 60.0% or higher being more preferred in that order. The transmittance at a wavelength of 600 nm can be, for example, 80.0% or lower or 75.0% or lower. Since a higher transmittance at a wavelength of 600 nm is preferable, and therefore higher transparency, the transmittance at a wavelength of 600 nm may exceed the values ​​exemplified here.

[0026] [Glass substrate] Examples of the glass substrate of the above-mentioned article include various glass substrates used in applications where a light-shielding function is desired. The shape of the substrate may be plate-like, curved, or may be a three-dimensional shape such as a container shape. The type of glass constituting the glass substrate is not particularly limited. For example, in the pharmaceutical field, it is desirable to block light rays in a wide wavelength range to preserve the quality of pharmaceuticals. Therefore, glass containers used for storing and / or distributing pharmaceuticals are desired to have excellent light-blocking properties against light rays in a wide wavelength range. For example, the amorphous iron(III) oxide coating is suitable as a coating for imparting light-blocking properties to the outer and / or inner surfaces of such glass containers (i.e., glass substrates). The amorphous iron(III) oxide coating is also suitable as a coating for imparting light-blocking properties to the outer and / or inner surfaces of glass containers (i.e., glass substrates) used for storing and / or distributing cosmetics, foods, etc. For example, borosilicate glass is known to transmit almost all light rays of 280 nm or more. By providing a coating that has excellent light-blocking properties against light rays in a wide wavelength range and is highly transparent on a glass substrate made of borosilicate glass, it is possible to impart preferable light-blocking properties for preserving the quality of pharmaceuticals, etc., while taking advantage of the high transparency (high transmittance) of borosilicate glass.

[0027] The article can have the amorphous iron(III) oxide coating on at least a portion of the glass substrate. Furthermore, the amorphous iron(III) oxide coating can be located, for example, as the outermost layer of the article at the location where the coating is provided. When the glass substrate has a front surface and a back surface, the article can have the amorphous iron(III) oxide coating on a portion or the entire surface of either or both of the front surface and the back surface. The amorphous iron(III) oxide coating can also be provided on at least a portion or the entire surface of a side surface of the glass substrate. The glass substrate on which the amorphous iron(III) oxide coating is provided can be a glass substrate alone, or a glass substrate having one or more layers laminated thereon. That is, the amorphous iron(III) oxide coating can be directly laminated on the surface of the glass substrate, or one or more other layers can be present between the amorphous iron(III) oxide coating and the glass substrate.

[0028] The above-mentioned article can be any article to which it is desired to impart a light-blocking function against light rays in a wide wavelength range. Specific examples of such articles include glass containers, glass windows, lenses, building materials, etc. Examples of containers include the containers described above.

[0029] In one embodiment, the glass substrate may be a glass container, and the amorphous iron(III) oxide coating may be a coating that covers at least a portion of the outer surface of the glass container. The amorphous iron(III) oxide coating can prevent the contents contained in the glass container from being deteriorated by ultraviolet light and high-energy visible light. Furthermore, the amorphous iron(III) oxide coating may have high transparency, which is preferable in that the presence of the coating does not interfere with visual inspection of the contents from the outside of the glass container. However, brown glass bottles, which are general-purpose light-blocking containers, contain inorganic salts such as iron compounds, and therefore leachable substances (e.g., iron ions) derived from the inorganic salts may be mixed into the contents. In particular, when the contents are biopharmaceuticals, there is a concern that the leachable substances may adversely affect the efficacy of the biopharmaceuticals. In contrast, since the coating on the outer surface of the glass container does not come into contact with the contents, providing the amorphous iron (III) oxide coating on the outer surface of the glass container is preferable in that elution from the coating does not get mixed into the contents.

[0030] [Manufacturing method] <Film forming composition> The coating can be formed by applying, to a glass substrate, a composition containing a β-diketone metal compound represented by the following formula 1. That is, one aspect of the present invention relates to a method for producing the above-mentioned article, which includes forming the coating by applying, to a glass substrate, a composition containing a β-diketone metal compound represented by the following formula 1.

[0031] [ka]

[0032] In formula 1, R 1and R 2 each independently represents a linear or branched alkyl group having from 1 to 8 carbon atoms. The alkyl group described in the present invention and this specification is a substituted or unsubstituted alkyl group, and is preferably an unsubstituted alkyl group.

[0033] The present inventors believe that the β-diketone metal compound represented by formula 1 can produce amorphous iron(III) oxide by reacting during the film-forming process using the above composition.

[0034] Formula 1 shows the structure of a β-diketone metal compound as a complex (iron complex). 1 and alkyl groups represented by R 2 Depending on the alkyl group represented by the formula (I), tautomerization may occur to form a β-diketone metal compound with a different bonding state between the oxygen atom and the iron atom. Such a β-diketone metal compound may take the form of a salt compound represented by the following formula 1-1. In the present invention and this specification, the β-diketone metal compound represented by formula 1 also includes the form that exists as such a salt compound. R in formula 1-1 1 and R 2 is R in Eq. 1 and R 2 is synonymous with.

[0035] [ka]

[0036] Formula 1 will be explained in more detail below.

[0037] In formula 1, R 1 and R 2 R each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. 1 and R 2 In one embodiment, R represents the same alkyl group, and in another embodiment, R represents a different alkyl group. 1In one embodiment, each of the three R represents the same alkyl group, in another embodiment, each of the three R represents a different alkyl group, and in another embodiment, two of the R represent the same alkyl group and the remaining one represents a different alkyl group. 2 The same is true for .

[0038] Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a 2-hexyl group, a heptyl group, a 2-ethylhexyl group, and an octyl group.

[0039] The β-diketone metal compound represented by formula 1 preferably has an alkyl group having 1 to 3 carbon atoms as the alkyl group, and is easily available. 1 and R 2 More preferably, all of are methyl groups.

[0040] Specific examples of the β-diketone metal compound represented by formula 1 include iron(III) acetylacetonate and tris(dipivaloylmethanato)iron(III).

[0041] The above β-diketone metal compounds can be synthesized by known methods and are also available as commercial products.

[0042] The film-forming composition contains one or more of the β-diketone metal compounds and can typically further contain a solvent. Only one solvent can be used, or two or more solvents can be mixed in any ratio. The solvent is preferably an organic solvent, more preferably an electron-donating organic solvent or an aromatic organic solvent, and even more preferably an aromatic electron-donating solvent from the viewpoint of enabling efficient film formation. In the present invention and this specification, the term "aromatic electron-donating solvent" refers to an organic solvent in which one or more substituents containing a heteroatom are directly bonded to an aromatic ring. The aromatic electron-donating solvent preferably satisfies at least one of the following conditions (1) to (3), more preferably two or more, and even more preferably all three. Satisfying the following condition (3) is preferable from the viewpoint of the storage stability of the iron oxide film-forming composition. (1) The aromatic ring is a benzene ring. (2) The heteroatom is an oxygen atom. (3) The above substituent does not have an active hydrogen atom.

[0043] Specific examples of aromatic electron-donating solvents include anisole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dihydrobenzofuran, and phenetole. From the viewpoints of film-forming properties and availability, anisole is more preferred. Anisole is an aromatic electron-donating organic solvent that satisfies all of the above (1) to (3).

[0044] The content of the β-diketone metal compound in the coating composition is preferably 40% by mass or less, more preferably 35% by mass or less, 30% by mass or less, and 25% by mass or less, in terms of producing a coating with sufficient thickness, producing a transparent coating with excellent visible light transmittance, pot life, and preventing nozzle clogging due to solvent evaporation, etc., expressed as % by mass, with the total amount of the composition being 100% by mass. Furthermore, the content is preferably 1% by mass or more, and more preferably 5% by mass or more, 10% by mass or more, and 15% by mass or more, in that order.

[0045] The film-forming composition may contain only the above-mentioned components, or may contain one or more known components in any proportion.

[0046] The above-mentioned film-forming composition allows for the formation of a film containing amorphous iron(III) oxide without a binder. The above-mentioned film-forming composition also allows for the strong adhesion of amorphous iron(III) oxide to the surface to be coated. Furthermore, compared to a film containing iron oxide formed using iron oxide particles and a binder, a film formed using the above-mentioned film-forming composition is preferable in terms of its high heat resistance.

[0047] <Application of the film-forming composition> The glass substrate to which the coating composition is applied is as described above. The coating composition can be applied by known methods such as droplet application, electrostatic application, spin coating, and dip coating. The droplet application method is preferred because it does not require specific substrate shapes. When a carrier gas is used in the droplet application method, the type of carrier gas is not particularly limited, and nitrogen, air, or the like can be used as the carrier gas. Specific examples of droplet application methods include spray application and mist CVD (chemical vapor deposition) methods. The spray application method involves spraying a coating solution from a nozzle. Commercially available spray application devices and spray application devices with known configurations can be used as spray application devices. The mist CVD method involves misting a coating solution using an ultrasonic mist generator or the like, and then supplying the mist to the substrate surface. Commercially available mist CVD application devices and mist CVD application devices with known configurations can be used as mist CVD application devices.

[0048] The coating composition can be applied in an atmosphere containing water and oxygen. The relative humidity of the "atmosphere containing water and oxygen" can be, for example, 20% or more and 100% or less. From the viewpoint of smooth coating formation, the relative humidity of the "atmosphere containing water and oxygen" is preferably 40% or more and 100% or less, and more preferably 50% or more and 100% or less, or 50% or more and 90% or less. The oxygen concentration in the "atmosphere in which water and oxygen are present" can be, for example, 5% by volume or more and 50% by volume or less, 10% by volume or more and 40% by volume or less, or 15% by volume or more and 30% by volume or less, with the total amount of gas in the atmosphere (excluding water vapor) being 100% by volume. The "atmosphere containing water and oxygen" can be, for example, air, preferably air containing water at a relative humidity within the above range. Alternatively, the "atmosphere containing water and oxygen" may be an atmosphere of a mixed gas of nitrogen, oxygen, and water instead of the air described above. As is well known, the oxygen concentration in air is about 20% by volume relative to the total amount of gas excluding water vapor. The composition can be applied, for example, under atmospheric pressure or under pressure, preferably under atmospheric pressure in the presence of water and oxygen. Applying the composition under atmospheric pressure is preferred because it is convenient in terms of the equipment.

[0049] The coating composition can be applied to a glass substrate by heating the glass substrate. The substrate temperature during application can be, for example, 450°C or less, 400°C or less, or less than 400°C, and the substrate temperature can be controlled by a known heating means such as a heater. In the present invention and this specification, the term "substrate temperature" refers to the temperature of the surface to be coated. The surface to be coated can be the surface of the glass substrate or the surface of a layer provided on the glass substrate.

[0050] The ambient temperature of the coating atmosphere can be, for example, 50°C or lower. The coating of the coating composition is preferably carried out at an ambient temperature of 50°C or lower and a substrate temperature of 450°C or lower. From the viewpoint of promoting the formation of amorphous iron(III) oxide, the ambient temperature of the coating is preferably 0°C or higher and 40°C or lower, and the substrate temperature is preferably 100°C or higher and 250°C or lower. Furthermore, the cycle of "coating-drying-heating" can be performed once or twice or more times. Repeating this cycle twice or more times can increase the thickness of the coating. Furthermore, various coating conditions, such as the amount of the coating composition to be applied, the coating speed, the size of droplets ejected from the spray nozzle when spray coating is performed, the distance between the substrate and the spray nozzle during coating, and the spray pressure, can be set depending on the content of the β-diketone metal compound in the composition, the specifications of the coating device used, the thickness of the coating to be formed, and the like. As described above, the thickness of the coating can affect the arithmetic mean roughness Ra of the surface of the amorphous iron (III) oxide coating opposite the glass substrate side. The preferred thickness of the amorphous iron (III) oxide coating is as described above.

[0051] [Iron oxide film forming composition] One aspect of the present invention relates to a composition for forming an iron oxide film, which comprises a β-diketone metal compound represented by Formula 1 and an aromatic electron-donating organic solvent. The composition for forming an iron oxide film allows efficient formation of an iron oxide film. In the present invention and this specification, the term "iron oxide film" refers to a film containing iron oxide. The composition for forming an iron oxide film contains an aromatic electron-donating organic solvent as a solvent. This can contribute to efficient film formation. Details of the aromatic electron-donating organic solvent are as described above.

[0052] In the present invention and this specification, the term "iron oxide coating" refers to a coating containing iron oxide. The β-diketone metal compound represented by Formula 1 contained in the composition for forming an iron oxide coating can function as a precursor of iron oxide. An iron oxide coating can be formed using the composition for forming an iron oxide coating containing such a β-diketone metal compound. The iron oxide coating formed can be, for example, an amorphous iron(III) oxide coating, but any iron oxide coating will do, and is not limited to an amorphous iron(III) oxide coating.

[0053] Another aspect of the present invention relates to a method for producing an article having a glass substrate and an amorphous iron(III) oxide coating. The method includes applying the iron oxide coating composition to a glass substrate to form the amorphous iron(III) oxide coating. The thickness of the coating thus formed can be, for example, 250 nm to 650 nm.

[0054] For details of the iron oxide coating composition, the method for producing the article using the iron oxide coating composition, and the iron oxide coating and glass substrate contained in the article produced by the method, please refer to the above descriptions. [Example]

[0055] The present invention will be described below based on examples, but the present invention is not limited to the embodiments shown in the examples.

[0056] [Examples 1 to 5, Comparative Examples 3 to 5] <Coating formation> 35 g of anisole dehydrated with molecular sieves was weighed as a solvent, and iron(III) acetylacetonate (R 1 and R 2 is a methyl group) was added and thoroughly stirred to obtain a coating liquid (film-forming composition). The coating solution obtained above was filled into the spray bottle of a spray coating apparatus. As the spray coating apparatus, a spray coating apparatus (nozzle-fixed type) described in JP-A-2011-170979 was used. As the substrate, a plate-shaped glass with a size of 5 cm × 5 cm (Corning glass substrate EAGLEXG) was placed on a substrate holder, heated to a substrate temperature of 200°C, and then, in air containing water at an atmospheric pressure, an ambient temperature of 25°C, and a relative humidity of 50%, the coating solution was sprayed (spray-coated) from a spray nozzle at a rate of 1 mL / min, and carrier gas nitrogen was set at 13 L / min. The spraying time was the time shown in the column of "film formation time" in Table 2 shown below. As the spray nozzle, an Atomax nozzle AM6 type manufactured by ATOMAX was used. The size of the droplets discharged from the spray nozzle was in the range of 3 to 20 μm, and spray coating was performed with the distance between the spray nozzle and the substrate being 23 cm, thereby forming a film on the substrate.

[0057] <Film thickness measurement> In each of Examples 1 to 5 and Comparative Examples 3 to 5, the film thickness of the film formed on the substrate was measured. The film thickness was measured using a stylus surface profilometer (DektakXT-S manufactured by Bruker Nano).

[0058] <Measurement of arithmetic mean roughness Ra> In each of Examples 1 to 5 and Comparative Examples 3 to 5, the arithmetic mean roughness Ra of the surface of the film (the surface opposite to the glass substrate side) formed on the substrate was determined as follows. The roughness curve defined by JIS (Japanese Industrial Standard) B 0601:2013 was calculated using a stylus surface profilometer (DektakXT-S manufactured by Bruker Nano), and the average of the absolute values at the reference length was expressed in nm units and taken as the arithmetic mean roughness Ra.

[0059] <XPS analysis> XPS analysis of the film formed on the substrate in Example 2 was performed, and it was confirmed that the film was an iron(III) oxide film. As the XPS apparatus, PHI5000VersaProbeII manufactured by ULVAC-PHI was used. In each of Example 1, Examples 3 to 5, and Comparative Examples 3 to 5, the film formed on the substrate is a film formed using the same coating solution as in Example 2. Therefore, like the film formed on the substrate in Example 2, it is an iron(III) oxide film.

[0060] <XRD Analysis> XRD analysis was performed on the films formed on the substrates in each of Examples 1 to 5 and Comparative Examples 3 to 5, and it was evaluated whether the films were amorphous films by the method described above. As the XRD apparatus, Rigaku UltimaIV was used. The results of the XRD analysis are shown in Table 1. As shown in Table 1, the films formed on the substrates in each of Examples 1 to 5 and Comparative Examples 3 to 5 were amorphous films.

[0061] [Table 1]

[0062] [Transmittance Measurement] The transmittance spectra of the films formed on the substrates in each of Examples 1 to 5 and Comparative Examples 3 to 5 were measured using a spectrophotometer manufactured by JASCO Corporation, and the transmittance at each wavelength of 360 nm, 450 nm, and 600 nm, as well as the average transmittance in the wavelength range of 600 nm or more and 800 nm or less, were determined.

[0063] [Comparative Example 1] Only 2.3 g of diethylzinc was added to 50.0 g of anisole and stirred well to obtain a coating solution. Spray coating of the above coating solution was carried out by the method described for Example 1, and a film was formed on the substrate. The film thus formed is a zinc oxide film. The transmittance measurement of the film formed on the substrate in Comparative Example 1 was carried out by the method described for Example 1 and the like.

[0064] [Comparative Example 2] In order to measure the transmittance of a typical brown glass bottle, a sample measuring approximately 2 cm x 2 cm was cut out from a commercially available FS screw cap bottle (a brown glass bottle made of borosilicate glass) manufactured by Maruemu Co., Ltd., and the transmittance was measured using the method described in Example 1, etc.

[0065] [Example 6] 35 g of anisole dehydrated with molecular sieves was weighed as a solvent, and 10 g of iron (III) acetylacetonate was added thereto, followed by thorough stirring to obtain a coating liquid (film-forming composition). The coating solution obtained above was filled into a spray bottle of a spray coating device. Then, a glass bottle (PYREX wide-mouth medium bottle (body outer diameter 40 mm × height 91 mm, borosilicate glass, transparent)) was heated as the substrate to a substrate temperature of 200°C to 450°C. An electric muffle furnace manufactured by Advantec was used for heating. The coating solution was sprayed (spray coating) for 15 minutes from a spray nozzle at a rate of 1 mL / min and a nitrogen carrier gas of 13 L / min under atmospheric pressure, an ambient temperature of 25°C, and a relative humidity of 50% in the presence of water. The spray nozzle used was an Atmax Nozzle AM6 manufactured by ATOMAX. The droplet size discharged from the spray nozzle was in the range of 3 to 20 μm, and spray coating was performed with a distance of 23 cm between the spray nozzle and the substrate, forming a coating on the outer surface of the substrate. If the substrate temperature dropped below 200°C to 450°C during spraying, the substrate was reheated as appropriate. A sample measuring approximately 2 cm x approximately 2 cm was cut out from the glass bottle having the coating formed on the outer surface, and the transmittance of the coating was measured by the method described in Example 1 and the like. In Example 6, a coating was formed using a coating solution of the same composition as in Example 2 for the same coating time as in Example 2, and by a coating method similar to that of Example 2. Therefore, the coating formed in Example 6 has the same arithmetic mean roughness Ra and film thickness as the coating formed in Example 2, and is an amorphous iron (III) oxide coating like the coating formed in Example 2.

[0066] The results are shown in Table 2.

[0067] [Table 2]

[0068] The results shown in Table 2 confirm that the coatings formed on the glass substrates in Examples 1 to 6 are capable of blocking light in a wide wavelength range (ultraviolet rays and high-energy visible light) and have high transparency.

[0069] [Study on Solvents (Example 5, Comparative Example 6, Comparative Example 7)] Except for changing the solvent to xylene (Comparative Example 6) or tetrahydrofuran (Comparative Example 7), a coating was formed on a substrate by the same method as in Example 5. In Comparative Examples 6 and 7, the coating time was the same as in Example 5, and therefore the coating amount of the coating liquid for forming a coating was the same.

[0070] Various evaluations were carried out by the methods described above for Comparative Examples 6 and 7. The results obtained are shown in Table 3 together with the results for Example 5.

[0071] [Table 3]

[0072] Xylene, which is the solvent used in Comparative Example 6, is an aromatic organic solvent, but does not fall under the category of aromatic electron-donating organic solvents. Tetrahydrofuran, the solvent used in Comparative Example 7, is an electron-donating organic solvent, but does not fall under the category of aromatic electron-donating organic solvents because it does not have an aromatic ring. The results shown in Table 3 confirm that, compared to Comparative Examples 6 and 7, which used these organic solvents, Example 5, which used an aromatic electron-donating organic solvent (specifically, anisole) as the solvent, was able to form a thicker coating, i.e., was able to form the film more efficiently.

[0073] [Study on iron oxide precursor compounds] (volatile) As described above, a specific example of a method for applying the film-forming composition is a spray coating method. From the viewpoint of film-forming properties by the spray coating method, the present inventors believe that a compound that can function as a precursor of iron oxide (also referred to as an "iron oxide precursor compound" or "precursor compound") is preferably a compound with low volatility for the following reasons. As the volatility of the precursor compound increases, the precursor compound volatilizes (evaporates) from the surface of the coating film formed by spray coating, thereby reducing the amount of the precursor compound in the coating film. Therefore, the present inventors believe that, from the viewpoint of enabling efficient film formation, it is preferable that the volatility of the precursor compound is low.

[0074] The volatility of various precursor compounds was evaluated by the following method. The precursor compounds (sample amount: 1 to 5 mg) shown in Table 4 below were introduced into a thermogravimetric differential thermal analyzer using a dedicated aluminum pan, and the temperature was increased from 40°C to 540°C at a rate of 20°C / min in an air atmosphere. The percentage (weight percentage) obtained by dividing the final residual weight (heated to 540°C) by the total sample weight introduced was defined as A: actual residual rate. The theoretical amount of iron oxide (Fe2O3) produced from the precursor compound was calculated as a percentage (weight percentage) and defined as B: theoretical residual rate. The ratio of A (actual residual rate) divided by B (theoretical residual rate) was used as an evaluation parameter for volatility. A higher ratio indicates a lower volatility of the precursor compound, and a lower ratio indicates a higher volatility of the precursor compound. The water content of iron(III) citrate n-hydrate was set to 5 wt% and was excluded from the calculation. In the table, "wt%" is an abbreviation for "weight %." Among the precursor compounds listed in Table 4, iron(III) acetylacetonate is a β-diketone metal compound represented by Formula 1. Iron(II) acetate was manufactured by Tokyo Chemical Industry Co., Ltd. (CAS No. 3094-87-9), iron(III) citrate n-hydrate was manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd. (CAS No. 207399-12-0), ferrocene was manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd. (CAS No. 102-54-5), and iron(III) acetylacetonate was manufactured by Tokyo Chemical Industry Co., Ltd. (CAS No. 14024-18-1).

[0075] [Table 4]

[0076] From the results shown in Table 4, the inventors believe that compared to iron(III) acetylacetonate, iron(II) acetate and ferrocene are highly volatile and therefore unsuitable for spray film formation.

[0077] (Solubility in organic solvents) The β-diketone metal compound represented by Formula 1 can be said to be a hydrophobic complex. It is presumed that the hydrophobic complex exhibits higher solubility in organic solvents than hydrophilic inorganic metal salt hydrates such as iron(III) citrate n-hydrate.

[0078] As described above, the β-diketone metal complex represented by formula 1 is considered to be preferable as an iron oxide precursor compound from the viewpoints of low volatility and high solubility in organic solvents. [Industrial Applicability]

[0079] One embodiment of the present invention is useful in various technical fields in which it is desirable to block light in a wide wavelength range (ultraviolet rays and high-energy visible light).

Claims

1. Formula 1 below: 【Chemistry 1】 (In formula 1, R １ and R ２ each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. a β-diketone metal compound represented by the formula: an aromatic electron donating organic solvent; A composition for forming an iron oxide film, comprising:

2. 2. The composition for forming an iron oxide film according to claim 1, wherein the aromatic electron-donating organic solvent is anisole.

3. The composition for forming an iron oxide film according to claim 1 , wherein the iron oxide film is an amorphous iron (III) oxide film.

4. The composition for forming an iron oxide film according to claim 2 , wherein the iron oxide film is an amorphous iron (III) oxide film.

5. 1. A method for making an article having a glass substrate and an amorphous iron (III) oxide coating, comprising: The method for producing the amorphous iron (III) oxide film comprises applying the composition for forming an iron oxide film according to claim 3 or 4 onto a glass substrate to form the amorphous iron (III) oxide film.

6. The manufacturing method according to claim 5 , wherein the coating has a thickness of 250 nm or more and 650 nm or less.

7. A glass substrate and an amorphous iron (III) oxide coating, The article has an arithmetic mean roughness Ra of the surface of the coating opposite to the glass substrate side of 100 nm or more and 250 nm or less.

8. The article according to claim 7, wherein the coating has a thickness of 250 nm or more and 650 nm or less.

9. The article according to claim 7, wherein the coating satisfies all of the following (1) to (3): (1) The average transmittance in the wavelength range of 600 nm or more and 800 nm or less is 70.0% or more. (2) The transmittance at a wavelength of 450 nm is 20.0% or less. (3) The transmittance at a wavelength of 360 nm is 5.0% or less.

10. the glass substrate is a glass container; and The article of claim 7 , wherein the coating is a coating that covers at least a portion of the exterior surface of the glass container.

11. The film thickness of the coating is 250 nm or more and 650 nm or less, The coating satisfies all of the following (1) to (3): the glass substrate is a glass container; and The article of claim 7 , wherein the coating is a coating that covers at least a portion of the exterior surface of the glass container. (1) The average transmittance in the wavelength range of 600 nm or more and 800 nm or less is 70.0% or more. (2) The transmittance at a wavelength of 450 nm is 20.0% or less. (3) The transmittance at a wavelength of 360 nm is 5.0% or less.

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