Articles having a film, optical instruments, paints, and methods for manufacturing articles.

Abstract

To provide an article having a membrane having designability and heat shielding property on a surface without discoloration or concerns on membrane detachment and membrane cracking.SOLUTION: There is provided a membrane containing a resin, an azo-based organic particle, and a particle containing Ti and O. While brightness is high since it becomes an azo-based organic particle 9 in which a color is changed by cutting an azo group of an azo-based organic particle 7, a TiOpart in the particle containing Ti and O is excited by a photocatalysis effect by sunlight and it becomes an excited particle 11 containing Ti and O, an electron (e-) is released to the resin, and a molecular chain of the resin is cut by electron energy. Thereby the rein becomes a discolored rein 12 and brightness is reduced. By irradiation of sunlight, brightness of the azo-based organic particle 7 is highly changed, discoloration is suppressed by a canceling effect as whole because brightness of the particle containing Ti and O is changed at low.SELECTED DRAWING: Figure 3-B

Description

Technical Field

[0001] The present invention relates to an article having a film, an optical device, a paint, and a method for manufacturing an article.

Background Art

[0002] The present invention relates to an article having a film, particularly a lens barrel of an optical device such as a camera, video, or broadcasting equipment, and other camera bodies, video bodies, surveillance cameras, weather cameras, etc. that may be used outdoors, as well as paints.

[0003] For example, on the surface of an optical device, a film having a function of suppressing the temperature rise of members due to sunlight when used outdoors is provided. Conventionally, as a method for suppressing the temperature rise of members due to sunlight, as shown in FIG. 1, a method of reflecting incident light 1 by sunlight as reflected light 2 with an infrared reflection film 4 of a base material 5 is known. By increasing the ratio of the reflected light 2 to the incident light 1, heat generation due to transmitted light 3 can be suppressed. As materials for increasing the reflectance, white titania having a high reflectance from visible light to the infrared region and pigments having a high infrared reflectance are often used. The solar energy distribution is 47% in the visible light region and 50% in the infrared region, and it is required to have a high reflectance in a wide range from visible light to the infrared region.

[0004] Since the above-mentioned infrared reflection film is an exterior film provided on the surface of the lens barrel of an optical device, the appearance quality of the color seen from the user's eyes is also important. That is, designability for adjusting the appearance color of the lens barrel to a desired color tone is also required. In addition, since optical devices are often used outdoors, in addition to heat insulation performance, light resistance under harsh sunlight conditions such as directly under the equator is also required.

[0005] Patent Document 1 discloses a lens barrel that can suppress temperature rise due to infrared radiation while adjusting the appearance color of the lens barrel to a desired color by providing a colored layer on top of an infrared reflective layer. Furthermore, Patent Document 1 enhances heat shielding performance by providing not only an infrared reflective layer and a colored layer, but also a heat insulating layer with a film thickness of 500 μm to 2000 μm. The colored layer in Patent Document 1 is formed by applying a paint containing an infrared-transmitting coloring substance to the surface of the infrared reflective layer, and the appearance color of the lens barrel can be adjusted to a desired color. Thus, Patent Document 1 discloses a film to be provided on the surface of a lens barrel that achieves both aesthetic appeal and heat shielding performance through a multilayer structure.

[0006] Patent Document 2 discloses a single-layer heat-shielding coating for use on gas cylinders, which has a relatively high lightness (L*) of 50 to 80 and a high solar reflectance of 40% or more. The heat-shielding coating in Patent Document 2 is described as having a relatively high visible light reflectance due to its relatively high lightness of 50 to 80, and therefore good heat-shielding performance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2009-139856 [Patent Document 2] Japanese Patent Publication No. 2011-085235 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, Patent Document 1 states that it is not possible to achieve both aesthetic appeal and heat shielding properties without a multilayer structure consisting of a colored layer, an infrared reflective layer, and an insulating layer. However, in multilayer films, infrared rays penetrate into the film due to unwanted interfacial reflection from each film layer, hindering the temperature rise suppression effect, and the film is prone to peeling from the film interface or cracking under harsh environmental conditions.

[0009] Furthermore, while Patent Document 2 for single-layer materials states that inorganic heat-shielding particles, organic heat-shielding particles, and combinations thereof are good for achieving relatively high brightness, organic heat-shielding particles have relatively low light resistance to sunlight, which may cause fading. [Means for solving the problem]

[0010] The present invention relates to an article comprising a substrate and a film provided on the substrate, wherein the film comprises a resin, azo organic particles, and particles containing Ti, a metal other than Ti, and O. When the aforementioned film is irradiated with sunlight, the brightness of the azo-based organic particles increases, The aforementioned Particles containing Ti, other metals, and O change the brightness of the resin to a lower level through photocatalytic action. It is characterized by the following:

[0011] Furthermore, the optical instrument of the present invention is an optical instrument having an optical element and / or an image sensor, and a housing that houses the optical element and / or image sensor inside, wherein a film is provided on the outside of the housing, and the film comprises a resin, azo organic particles, and particles containing Ti, a metal other than Ti, and O. When the aforementioned film is irradiated with sunlight, the brightness of the azo-based organic particles increases, The aforementioned Particles containing Ti, other metals, and O change the brightness of the resin to a lower level through photocatalytic action. It is characterized by the following:

[0012] Furthermore, the paint of the present invention hardenability A paint comprising a resin, azo organic particles, and particles containing Ti, metals other than Ti, and O, When the cured paint is irradiated with sunlight, the brightness of the azo-based organic particles increases, and the particles containing Ti, other metals, and O change the brightness of the curable resin to a lower level through photocatalytic action. A paint characterized by the following features. [Effects of the Invention]

[0015] The present invention provides an article having a film on its surface that combines aesthetic appeal and heat-shielding properties. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional diagram showing the reflection and absorption of sunlight when a film to be applied to the surface of an optical instrument is formed on the upper surface of a substrate. [Figure 2-A] This is a schematic cross-sectional view illustrating the film of the first embodiment. [Figure 2-B] This is a schematic cross-sectional view illustrating the film of the first embodiment. [Figure 2-C]It is a schematic cross-sectional view for explaining the film of the first embodiment. [Figure 2-D] It is a schematic cross-sectional view for explaining the film of the first embodiment. [Figure 3-A] It is a schematic cross-sectional view for explaining the film of the first embodiment. [Figure 3-B] It is a schematic cross-sectional view for explaining the film of the first embodiment. [Figure 4-A] It is an external view showing an example of an interchangeable lens for a camera having a lens barrel, which is one aspect of the optical device of the present invention. [Figure 4-B] It is a cross-sectional view showing an example of an interchangeable lens for a camera having a lens barrel, which is one aspect of the optical device of the present invention. [Figure 5] It is a schematic diagram showing a measurement mode of reflectance by a spectrophotometer. [Figure 6] It is a schematic diagram showing a method for evaluating temperature. [Figure 7] It is a schematic cross-sectional view showing the film of the second embodiment. [Figure 8] It is a schematic cross-sectional view showing the film of the third embodiment.

Mode for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described.

[0018] (First Embodiment) First, an article having a film with excellent heat insulation performance, which has little discoloration (fading) against sunlight even when the color is light (even when the brightness is high), will be described. Discoloration in the present invention includes discoloration due to fading.

[0019] [Method for achieving both heat insulation effect of a film with high brightness and excellent heat insulation performance and suppression of discoloration by sunlight] (Regarding the relationship between discoloration of azo-based organic particles by sunlight and heat insulation performance) The relationship between discoloration of azo-based organic particles by sunlight and heat insulation performance will be described.

[0020] Azo organic particles are colored pigments that have an azo group, RN=N-R', as a chemical structure in their molecules. Azo organic particles have a higher infrared reflectivity compared to inorganic pigments. When exposed to sunlight, the azo group in azo organic particles may be cleaved, resulting in 2R and N2. Azo organic particles derive their color from the N=N group and the surrounding atomic arrangement within the particle; therefore, when the N=N group is cleaved, the color disappears and the brightness increases. In this specification, azo organic particles are defined as colored pigments that have an azo group, RN=N-R', as a chemical structure in their molecules. Furthermore, colored pigments whose color has changed due to the cleavage of the N=N group in a colored pigment with an azo group, RN=N-R', are also defined as azo organic particles.

[0021] To increase the reflectivity of visible light and improve heat shielding performance, the brightness of the surface of the optical instrument needs to be 50 or higher, and azo-based organic particles with high reflectivity must be used. If a film is formed on the surface of the optical instrument, that film must also have high brightness. Furthermore, it is necessary to use azo-based organic particles with high reflectivity, but a film with high brightness requires a small amount of colorant. In other words, as shown in Figure 2-A, the amount of azo-based organic particles 7, which are the colorant, is such that they are sparsely present in the resin 8. Sparse presence means, for example, that the content of the azo-based organic particles is between 0.1% and 0.4% by volume relative to the volume of the film. When sunlight 6 is irradiated and the azo group is cleaved, the azo-based organic particles 9 lose their color. As shown in Figure 2-B, because they are sparsely present in the resin 8, the ratio of azo-based organic particles 9 with cleaved azo groups to azo-based organic particles 7 with intact azo groups is high, and the color of the film formed on the surface of the optical instrument changes significantly.

[0022] On the other hand, as shown in Figure 2-C, films with a relatively low brightness of less than 50 have a large amount of azo organic particles 7 in the resin 8. Therefore, even if the azo groups are similarly cleaved by sunlight 6, as shown in Figure 2-D, the ratio of azo organic particles 9 with cleaved azo groups to azo organic particles 7 with intact azo groups is high. Thus, the color change of the film formed on the surface of optical equipment is relatively small. However, films with a low brightness of less than 50 have high absorption of visible light and low reflection of sunlight, resulting in poor heat shielding performance.

[0023] (A method for achieving both heat shielding effect and discoloration suppression according to the present invention) As described above, while films with a high brightness of 50 or more and containing azo-based organic particles 7 have a high heat-shielding effect, they have the problem of discoloration due to sunlight.

[0024] The inventors of this invention diligently investigated methods to achieve both heat shielding effect and discoloration suppression, and found that discoloration caused by sunlight can be suppressed by further adding particles containing Ti and O to the film. The particles containing Ti and O may also contain one or more inorganic metals in addition to Ti and O, as will be described in detail later.

[0025] As shown in Figure 3-A, the film according to the present invention contains azo organic particles 7, resin 8, and particles 10 containing Ti and O. In addition, it is more preferable if the brightness is adjusted to 50 or higher, as this enhances the heat shielding effect. When sunlight 6 is irradiated onto the film according to the present invention, as shown in Figure 3-B, the azo groups of the azo organic particles 7 are cleaved, resulting in discolored azo organic particles 9, thus increasing the brightness. On the other hand, the Ti and O particles 10 have their TiO2 portions excited by the photocatalytic action of sunlight, becoming excited Ti and O particles 11. The Ti and O particles 11 excited by sunlight release electrons (e-) into the resin 8, and the molecular chains of the resin 8 are cleaved by the electron energy. As a result, the resin 8 becomes discolored resin 12, and the brightness decreases.

[0026] Thus, in the film according to the present invention, when irradiated with sunlight 6, the brightness of the azo organic particles 7 changes to a high level, while the brightness of the particles 10 containing Ti and O changes to a low level. As a result, overall color change is suppressed by a cancellation effect.

[0027] [Article of the present invention] The articles of the present invention are formed on a plastic or metal substrate by applying the coating of the present invention to the substrate, thereby forming a film with excellent heat-shielding properties (the film according to the present invention) on its surface. In other words, the articles of the present invention have a film with excellent heat-shielding properties (the film according to the present invention) on their surface. The articles of the present invention are particularly suitable for use in optical equipment. Optical equipment includes, for example, interchangeable lenses used in cameras, video cameras, broadcasting equipment, etc. Other image forming devices that may be used outdoors and form an image using light transmitted through a lens include camera bodies, video cameras, surveillance cameras, weather cameras, etc. When the optical equipment of the present invention is used outdoors, a higher heat-shielding effect is achieved by forming the film according to the present invention on the part that is irradiated by sunlight (referred to as the outer surface). Figure 4-A shows the appearance of an interchangeable lens for a camera, which is one embodiment of the optical equipment of the present invention, including a lens barrel having a holding part for holding the lens. The interchangeable lens has a lens barrel 30 and a tripod mount 33, and the lens barrel 30 is composed of a lens, a fixed cylinder 31, an annular member 32, etc. The optical instrument of the present invention has a film with excellent heat-shielding properties (the film according to the present invention) formed on the surfaces of the fixed cylinder 31 of the lens barrel 30, the annular member 32, the tripod mount 33, etc. The material of the fixed cylinder 31, the annular member 32, and the tripod mount 33 is not particularly limited and may be plastic or metal.

[0028] Figure 4-B shows a cross-sectional view of a single-lens reflex digital camera, which includes a lens barrel having a holder for holding the lens, and is a configuration of an optical device according to the present invention, with an interchangeable lens attached.

[0029] The optical instruments of the present invention refer to devices on which the film of the present invention is formed, such as binoculars, microscopes, semiconductor exposure apparatuses, interchangeable lenses, cameras, and other electronic devices, and in particular, devices equipped with an optical system including optical elements. Alternatively, it refers to devices that generate images using light that has passed through optical elements.

[0030] Furthermore, the optical device of the present invention may be a camera system such as a digital still camera or a digital video camera, or an electronic device such as a mobile phone that has an image sensor that receives light that has passed through the optical element of the present invention. In addition, it may also take the form of a module mounted on an electronic device, for example, a camera module which may be used as the imaging device.

[0031] In Figure 4-B, the camera body 602 and the interchangeable lens 601, which includes an outer barrel 620 of the lens barrel on which the film of the present invention is formed, are coupled together, and the interchangeable lens 601 is detachable from the camera body 602.

[0032] Light from the subject passes through an optical system consisting of multiple lenses 603, 605, etc., arranged on the optical axis of the photographic optical system within the interchangeable lens 601, and is received by the image sensor.

[0033] Here, the lens 605 is supported by the inner barrel 604 of the lens barrel and is movable relative to the outer barrel 620 of the lens barrel for focusing and zooming.

[0034] During the observation period before shooting, light from the subject is reflected by the main mirror 607 inside the camera body housing 621, passes through the prism 611, and the image is projected onto the photographer through the viewfinder lens 612. The main mirror 607 is, for example, a half-mirror, and the light that passes through the main mirror is reflected by the sub-mirror 608 towards the AF (autofocus) unit 613, and this reflected light is used, for example, for distance measurement. The main mirror 607 is also attached and supported by the main mirror holder 640 by adhesive or other means. During shooting, the main mirror 607 and sub-mirror 608 are moved out of the optical path via a drive mechanism (not shown), the shutter 609 is opened, and the image of the photographic light incident from the lens barrel 601 is projected onto the image sensor 610. The aperture 606 is configured to change the brightness and depth of field during shooting by changing the aperture area.

[0035] [Damage paint] First, the paint and method for manufacturing the present invention will be described.

[0036] The paint of the present invention comprises at least a resin, azo-based organic particles, and particles containing Ti and O.

[0037] (Azo organic particles) The azo organic particles contained in the paint of the present invention will be described below.

[0038] Any azo organic particles containing an azo group can be used as the azo organic particles in the paint of the present invention. The azo organic particles in the paint of the present invention can be black, yellow, red, or orange, but black is preferred because it exhibits less color change (a*, b*) when fading occurs due to sunlight. Furthermore, a high reflectivity to sunlight is preferred, and it is preferable to select a material with a solar reflectance of over 10% for the azo organic particles alone. Examples of azo organic particles include nickel azo pigments, insoluble azo pigments, soluble azo pigments, high molecular weight azo pigments, and azomethine azo pigments. These azo organic particles may be used individually or in combination of multiple types.

[0039] The average particle size of the azo organic particles contained in the paint of the present invention is preferably 10 nm to 5 μm, and more preferably 50 nm to 2 μm. If the average particle size of the azo organic particles of the present invention is less than 10 nm, the surface area of ​​the particles increases, which may lead to a deterioration in light resistance and discoloration. Furthermore, if the average particle size of the azo organic particles contained in the paint of the present invention exceeds 5 μm, the unevenness of the coating film increases, which may lead to a deterioration in film thickness accuracy and a decrease in accuracy such as focusing.

[0040] Azo particles can be of any shape. Examples include spherical, plate-shaped, cubic, elliptical, plate-shaped, layered, hollow, star-shaped, needle-shaped, and other irregular shapes. These azo organic particles can be of one type or a combination of multiple types.

[0041] Furthermore, the content of azo organic particles in the paint of the present invention is preferably 0.1% by weight or more and 1.0% by weight or less, and more preferably 0.15% by weight or more and 0.5% by weight or less, relative to the non-volatile components in the paint. If the content of azo organic particles is less than 0.1% by weight, the brightness of the film may become too high, potentially worsening its antifouling properties. Conversely, if the content of azo organic particles is 1.0% by weight or more, the brightness of the film may become too low, worsening its solar reflectance. The content of azo particles relative to the non-volatile components in the paint can be measured after the paint has cured, using the same method as for measuring the content of azo organic particles in the film according to the present invention, as described later.

[0042] (Particles containing Ti and O) Next, the particles containing Ti and O included in the paint of the present invention will be described. As mentioned above, the particles containing Ti and O included in the paint of the present invention may also contain one or more inorganic metals in addition to Ti and O. Including one or more inorganic metals in addition to Ti and O changes the color of the particles, and they can be used as particles (pigments) for adjusting the color. An example of the particles containing Ti and O of the present invention is titania. Other examples include (Ti, Ni, Sb)Ox, (Ti, Cr, Sb)Ox, (Ti, Fe, Zn)Ox, (Co, Cr, Zn, Al, Ti)Ox, (Co, Cr, Zn, Ti)Ox, (Co, Al, Ni, Ti)Ox, etc. For example, (Ti, Ni, Sb)Ox is a crystalline pigment obtained by calcining titanium oxide, nickel oxide, and antimony oxide. The particles containing Ti and O of the present invention are preferably one or a mixture selected from titania, (Ti, Sb, Cr)O2, and (Ti, Fe, Zn)O2.

[0043] Since these Ti and O-containing particles need to cleave the molecular chains of the resin through photocatalytic action, it is preferable that there is little to no coating of light-resistant silica or the like. The content of Ti and O-containing particles relative to the non-volatile components in the paint can be measured after the paint has cured using the same method as the measurement of the content of Ti and O-containing particles in the film according to the present invention, as described later.

[0044] The content of Ti and O-containing particles in the paint of the present invention is preferably 0.1% to 1.6% by weight, and more preferably 0.3% to 0.7% by weight, relative to the non-volatile components in the paint. If the content of Ti and O-containing particles in the paint of the present invention is less than 0.1%, the photocatalytic effect when irradiated with sunlight will be low, which may cause a large change in the brightness of the film according to the present invention. If the content of Ti and O-containing particles in the paint of the present invention exceeds 1.6% by weight, the photocatalytic effect when irradiated with sunlight will be too high, which may cause a large change in the brightness of the film according to the present invention.

[0045] Furthermore, the average particle size of the Ti and O-containing particles in the paint of the present invention is preferably 10 nm to 5 μm, and more preferably 50 nm to 2 μm. If the average particle size of the Ti and O-containing particles of the present invention is less than 10 nm, the surface area of ​​the particles increases, which may increase the photocatalytic effect and cause discoloration. Also, if the average particle size of the Ti and O-containing particles of the present invention exceeds 5 μm, the unevenness of the coating film increases, which may worsen the film thickness accuracy and reduce the accuracy of focusing and other functions.

[0046] When the content of azo organic particles in the paint is considered to be 100% by weight, the content of particles containing Ti and O is preferably between 10% by weight and 1600% by weight. If it falls outside this range, there is a risk of significant changes in brightness.

[0047] (resin) Next, the resin contained in the paint of the present invention will be described.

[0048] Examples of resins included in the paint of the present invention include epoxy resin, urethane resin, acrylic resin, urethane acrylic resin, phenolic resin, and alkyd resin. These resins may be used individually or in combination of multiple types.

[0049] Furthermore, the resin content in the paint of the present invention is preferably 5% to 80% by weight, and more preferably 15% to 50% by weight, relative to the non-volatile components in the paint. If the resin content of the present invention is less than 5% by weight, the adhesion to the substrate may deteriorate. Also, if the resin content of the present invention exceeds 50% by weight, the solar reflectance may deteriorate. The resin content relative to the non-volatile components in the paint can be measured after the paint has cured, using the same method as for measuring the resin content in the film according to the present invention, as described later.

[0050] (Particles (inorganic pigments) for adjusting brightness) The coating of the present invention may contain inorganic pigments other than particles containing Ti and O as particles for adjusting brightness. The brightness of the film of the present invention is preferably 50 or higher, and more preferably 71 to 80. In this specification, inorganic pigments other than particles containing Ti and O are simply referred to as inorganic pigments.

[0051] The particles (inorganic pigments) used to adjust the brightness of the paint of the present invention to 50 or higher can be any material as long as they are particles capable of adjusting brightness. Preferably, the particles (inorganic pigments) used to adjust the brightness to 50 or higher in the present invention have a high solar reflectance, and more preferably, the solar reflectance of the material alone exceeds 10%. Examples of particles (inorganic pigments) used to adjust the brightness to 50 or higher in the present invention include titanium dioxide (titanium oxide) with a silica-coated surface, alumina, zirconia, silica, hollow silica, and zinc oxide. These materials may be used individually or in combination. If the brightness of a film formed using the paint of the present invention falls below 50, the solar reflectance decreases, and the temperature reduction effect deteriorates. If the brightness of a film formed using the paint of the present invention exceeds 80, the color may become too white, making dirt more noticeable. In this specification, titanium dioxide with a silica-coated surface refers to titanium dioxide particles in which at least a portion of the surface is covered with silica. The particles (inorganic pigments) used to adjust the brightness to 50 or higher are preferably titanium dioxide particles with a silica coating on their surface.

[0052] The titanium dioxide particles coated with silica can be rutile-type titanium dioxide or anatase-type titanium dioxide. Furthermore, at least a portion of the titanium dioxide is coated with silica. If the titanium dioxide is not coated with silica, discoloration of the titanium dioxide in an oxygen-free atmosphere increases, and the reflectivity decreases. In addition to silica, the titanium dioxide may also be coated with multiple other materials such as zirconium oxide, aluminum oxide, or organic substances. The average particle size of the silica-coated titanium dioxide particles is 0.2 μm or larger. If the average particle size of the silica-coated titanium dioxide particles is less than 0.2 μm, the charge of the particles decreases, making it difficult to attract the silica particles (described later), which may lead to increased discoloration in an oxygen-free atmosphere. On the other hand, if the average particle size of the silica-coated titanium dioxide particles exceeds 5 μm, the surface irregularities of the coating increase, worsening the film thickness accuracy, which may reduce the accuracy of focusing and other functions. Therefore, it is preferable that the average particle size of the silica-coated titanium dioxide particles is 5 μm or less.

[0053] The content of particles (titanium oxide particles coated with silica) for adjusting the brightness to 50 or higher in the paint of the present invention is preferably 5% to 80% by weight, and more preferably 10% to 40% by weight, relative to the non-volatile components in the paint. If the content of particles (titanium oxide particles coated with silica) for adjusting the brightness to 50 or higher in the present invention is less than 5% by weight, the coloring power will be weak, and it may be difficult to achieve a brightness of 50 or higher. Furthermore, if the content of particles (titanium oxide particles coated with silica) for adjusting the brightness to 50 or higher exceeds 80% by weight, the brittleness of the film may worsen and become brittle. The content of particles for adjusting the brightness to 50 or higher relative to the non-volatile components in the paint can be measured after the paint has hardened, using the same method as for measuring the content of particles for adjusting the brightness to 50 or higher in the film according to the present invention, as described later.

[0054] In this specification, silica-coated titanium oxide particles refer to silica-coated titania particles if at least a portion of the surface of the titanium oxide particles is covered with silica. Preferably, 80% or more of the total surface area of ​​the silica-coated titanium oxide particles is covered with silica. Furthermore, in this specification, silica-coated titania particles are an example of an inorganic pigment and an example of particles for adjusting the brightness to 50 or higher.

[0055] (Silica particles) In this embodiment, silica particles may also be included. The average particle size is preferably 10 nm to 110 nm. When the average particle size is 10 nm to 110 nm, it has the effect of filling in the minute defects in the silica of the titania particles whose surfaces are coated with silica, and has the effect of suppressing discoloration in an oxygen-free atmosphere. If the average particle size of the silica particles in this embodiment is less than 10 nm, the ability to fill in the minute defects in the silica of the titanium oxide particles whose surfaces are coated with silica decreases, so the effect of suppressing discoloration in an oxygen-free atmosphere may deteriorate. Also, if the average particle size of the silica particles contained in the paint of the present invention exceeds 110 nm, the adsorption capacity to titanium oxide decreases, so the effect of reducing discoloration in an oxygen-free atmosphere may deteriorate.

[0056] The silica particles can be of any shape. Examples of silica particle shapes include spherical, amorphous, star-shaped, chain-like, hollow, and porous. These silica particles can be of one type or a combination of multiple types.

[0057] In this embodiment, the particle diameter of the silica particles 128 is the average particle diameter based on the number of particles. The average particle diameter of the silica particles 128 can be measured by dynamic light scattering when the paint is in its pre-coating state. When measuring from the state of the film, first, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the silica particles 128 are analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) to determine the particle diameter of each silica particle 128 and calculate its average value. Finally, the average value of the five locations is calculated. This average value of the five locations is taken as the average particle diameter of the silica particles contained in the film according to this embodiment. In this embodiment, for example, as shown in Figure 7(c), if silica particles 128 between 10 nm and 50 nm aggregate to form secondary particles, the coatability can be improved if the longitudinal length of the secondary particles is between 50 nm and 350 nm. In particular, it is preferable to select chain-like silica particles in which spherical silica particles 128 are linked together. Chain-like silica particles in which spherical silica particles 128 are linked together are preferable because when applying a coating for forming a light-shielding film, the space created by the silica particles 128 is large, making it easier for the particles 127 to move.

[0058] The silica particle content is 0.6% by mass or more and 14% by mass or less relative to the non-volatile components in the paint, preferably 1% by mass or more and 10% by mass or less. If the silica particle content is less than 0.6% by mass, the minute defects in the silica of the silica-coated titanium oxide particles cannot be filled, which may worsen discoloration in an oxygen-free atmosphere. Also, if the silica particle content of the present invention exceeds 14% by mass, the haze of the coating film will worsen, which may worsen the reflectivity. The silica particle content relative to the non-volatile components in the paint can be measured after the paint has cured, using the same method as for measuring the silica particle content in the film according to the present invention, as described later.

[0059] (Dispersant) The dispersant included in the paint of this embodiment can be any dispersant that has a greater effect of agglomerating organic pigments than inorganic pigments. It is particularly preferable that it contains an alkylol ammonium salt. Originally, the role of a dispersant is to adsorb onto the surface of pigments and separate them from one another, thereby maintaining a constant distance between pigments and preventing them from agglomerating. However, in this embodiment, it is preferable that the dispersant agglomerates organic pigments and disperses inorganic pigments.

[0060] Furthermore, the dispersant of the present invention preferably has at least an acid group. It is also preferable that the dispersant of the present invention has an acid value (mgkOH / g) of 30 to 100. An acid value (mgkOH / g) in the range of 30 to 100 allows for more appropriate deposition of the organic pigment towards the air interface. Additionally, it is preferable that the amount of dispersant added is greater than the amount of organic pigment. If the amount of dispersant is less, some of the organic pigment will disperse, resulting in less segregation towards the air interface.

[0061] Furthermore, the amount of dispersant contained in the paint of the present invention is preferably 0.1% by weight or more and 10.0% by weight or less, relative to the non-volatile components in the paint, and more preferably 0.15% by weight or more and 7.0% by weight or less. If the amount of dispersant is less than 0.1% by weight, the heat shielding performance deteriorates. Also, if the amount of dispersant is 10.0% by weight or more, the refractive index of the layer becomes lower, and the reflection due to the refractive index difference becomes smaller.

[0062] (solvent) This section explains the solvents contained in paints.

[0063] Any material may be used as the solvent. Examples of solvents include water, paint thinner, ethanol, isopropyl alcohol, and n-butyl alcohol. Other examples include ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, toluene, xylene, acetone, cellosolves, glycol ethers, and ethers. One type of solvent or a combination of several types may be used.

[0064] The preferred viscosity of the paint of the present invention is 10 mPa·s or more and 10,000 mPa·s or less, and more preferably 50 mPa·s or more and 500 mPa·s or less. If the viscosity of the paint is less than 10 mPa·s, there may be areas where the thickness of the heat-shielding film after application is thin. Also, if it exceeds 10,000 mPa·s, the applicability of the paint may decrease.

[0065] (Other additives) The paint of the present invention may contain any other additives. Examples include dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, matting agents, preservatives, UV absorbers, antioxidants, coupling agents, and inorganic and organic fine particles for adjusting the color other than those mentioned above.

[0066] 《Method of manufacturing paint》 The method for manufacturing the paint of the present invention will be described below.

[0067] As a method for manufacturing the paint of the present invention, any method can be used as long as azo organic particles, particles containing Ti and O, and particles for adjusting the brightness to 50 or higher are dispersed in the paint. Examples include bead mills, ball mills, jet mills, three-roller mills, planetary rotating devices, mixers, ultrasonic dispersers, homogenizers, and the like.

[0068] Article of the present invention Next, the article of the present invention will be described.

[0069] The articles of the present invention are formed on a plastic or metal substrate by applying the coating of the present invention to the substrate, thereby forming a film with excellent heat-shielding properties (the film according to the present invention) on its surface. In other words, according to this embodiment, it is possible to provide articles such as optical instruments that have a film on their surface that combines aesthetic appeal and heat-shielding properties, without the worry of film peeling or cracking. Therefore, the articles of the present invention have a film with excellent heat-shielding properties (the film according to the present invention) on their surface. Furthermore, it is preferable that the film is formed at least on the outside of the substrate (the side exposed to the external environment). In addition, the film according to the present invention may be in close contact with the substrate, or a primer layer to improve adhesion may be provided between the substrate and the film according to the present invention.

[0070] (base material) Any material can be used as the base material, but metals and plastics are preferred. Examples of metal materials include aluminum, titanium, stainless steel, magnesium alloys, and lithium-magnesium alloys. Examples of plastics include polycarbonate resin, acrylic resin, ABS resin, and fluororesin.

[0071] Furthermore, while the film thickness of the substrate can be any thickness, it is preferably 0.5 mm to 5 mm, and more preferably 0.5 mm to 2 mm. If the film thickness is less than 0.5 mm, it becomes difficult to maintain the shape of the lens barrel. Also, if the film thickness exceeds 5 mm, the cost of the component increases.

[0072] (Primer) Primers may also be used to improve the adhesion between the substrate and the film.

[0073] Any material can be used as the primer, but examples include epoxy resin, urethane resin, acrylic resin, silicone resin, and fluororesin. The primer may also contain particles of the present invention or other particles, colorants, dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, organic colorants, inorganic colorants, preservatives, UV absorbers, antioxidants, coupling agents, and solvent residues.

[0074] Furthermore, the primer film thickness is preferably 2 μm to 30 μm, and more preferably 5 μm to 20 μm. If the film thickness is less than 2 μm, the adhesion of the film may decrease, and if it exceeds 30 μm, it may adversely affect the positional accuracy.

[0075] (Film thickness of the film according to the present invention) The film according to the present invention preferably has a film thickness of 10 μm or more and 70 μm or less. If the film thickness is less than 10 μm, the solar reflectance may decrease. Furthermore, if the film thickness exceeds 70 μm, it may adversely affect the positional accuracy of optical instruments.

[0076] Methods for manufacturing articles The method for manufacturing an article according to the present invention can utilize any coating method and curing method as long as the coating of the present invention can be uniformly applied to a substrate in a thickness of 10 μm to 70 μm.

[0077] Application methods include brush application, spray application, dip coating, and transfer. The heat-shielding film can be a single-layer or multi-layer coating, and it may also be textured to enhance its aesthetic appeal.

[0078] Furthermore, the curing method can be left at room temperature, or curing can be accelerated by applying heat or ultraviolet light. Methods of curing by applying heat include heating furnaces, heaters, and infrared heating. The curing temperature is preferably from room temperature to 400°C, and more preferably from room temperature to 200°C.

[0079] Thus, the article of the present invention is formed on a plastic or metal substrate by applying the coating of the present invention to the substrate, thereby forming a film with excellent heat-shielding properties (the film according to the present invention) on its surface. The film thus formed contains at least a resin, azo organic particles, and particles containing Ti and O.

[0080] (Azo organic particles) The content of azo organic particles in the film according to the present invention is preferably 0.1 area% to 0.4 area%, and more preferably 0.15 area% to 0.3 area%. If the content of azo organic particles is less than 0.1 area%, the brightness of the film becomes too high, and the antifouling properties deteriorate. Conversely, if the content of azo organic particles is 0.4 area% or more, the brightness of the film becomes too low, and the solar reflectance deteriorates.

[0081] The content of azo organic particles in the film according to the present invention shall be measured as follows. First, five cross-sections (3 μm × 3 μm) are cut from near the surface of the film according to the present invention and magnified 100,000 times using transmission electron microscopy (TEM). If the particles are large, five cross-sections (10 μm × 10 μm) are cut and magnified 30,000 times using transmission electron microscopy (TEM). Next, the azo organic particles are analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area is calculated. Finally, the content of azo organic particles in the film according to the present invention is calculated from the average value of the five locations. Since this analysis method takes the average of the cross-sectional areas of the five locations, the theoretical volume value and the analytical value obtained by this method will be approximately the same.

[0082] (Particles containing Ti and O) The content of Ti and O-containing particles in the film according to the present invention is preferably 0.1 area% to 1.0 area% relative to the cross-sectional area of ​​the film, and more preferably 0.2 area% to 0.7 area%. If the content of Ti and O-containing particles in the present invention is less than 0.1 area%, the photocatalytic effect when irradiated with sunlight will be low, which may cause a large change in the brightness of the film according to the present invention. If the content of Ti and O-containing particles in the present invention exceeds 1.0 area%, the photocatalytic effect when irradiated with sunlight will be too high, which may cause a large change in the brightness of the film according to the present invention.

[0083] The content of Ti and O particles in the film according to the present invention shall be measured as follows. First, five cross-sections (3 μm × 3 μm) are cut from near the surface of the film according to the present invention. These five cross-sections are magnified 100,000 times using a transmission electron microscope (TEM). If the particles are large, five cross-sections (10 μm × 10 μm) are cut and magnified 30,000 times using a transmission electron microscope (TEM). Next, the particles at the five locations are analyzed using Energy Dispersive X-ray Spectroscopy (EDS) to calculate the content per unit area. Finally, the content of Ti and O particles in the film according to the present invention is calculated from the average value of the five locations, and this value is taken as the content of Ti and O particles. In this embodiment, the content calculated by this method is expressed as area %.

[0084] Furthermore, particles containing Ti and O are defined as particles where the contact area between the Ti and O-containing particle and the resin is 20% or more of the surface area of ​​the Ti and O-containing particle. Specifically, the cross-section cut out to calculate the content is subjected to the same surface analysis. Then, if the length of the contour line in contact with the resin is 20% or more of the total contour line length of the cross-section of the Ti and O-containing particle, it is considered to be a Ti and O-containing particle.

[0085] Furthermore, when the content of the azo organic particles of the present invention is set to 100 area%, the content of particles containing Ti and O is preferably 25 area% to 1000 area%, and more preferably 50 area% to 500 area%. If it exceeds 1000 area%, there is a risk of a large change in brightness. Also, if it falls below 25 area%, there is a risk of a large change in brightness.

[0086] (resin) The resin content in the film according to the present invention is preferably 5% to 80% and more preferably 30% to 60% when the cross-sectional area of ​​the film is considered as 100% of the area. If the resin content of the present invention is less than 5% of the area, the adhesion to the substrate may deteriorate. Furthermore, if the resin content of the present invention exceeds 60% of the area, the solar reflectance may deteriorate.

[0087] The resin content in the film according to the present invention was measured as follows. First, five cross-sections (3 μm × 3 μm) near the surface of the film according to the present invention were cut out and magnified 100,000 times using a transmission electron microscope (TEM). If the particles were large, five cross-sections (10 μm × 10 μm) were cut out and magnified 30,000 times using a transmission electron microscope (TEM). Next, the resin was analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area was calculated. Finally, the resin content in the film according to the present invention was calculated from the average value of the five locations, and this value was taken as the resin content in the film.

[0088] (Particles (inorganic pigments) for adjusting brightness) The content of particles (inorganic pigments) for adjusting brightness in the film according to the present invention is preferably 10% to 80% and more preferably 20% to 60% when the unit cross-sectional area of ​​the film is 100%. If the content of particles for adjusting brightness in the present invention is less than 10% of the present invention, the coloring power will be weak, and it may be difficult to achieve a brightness of 50 or higher. Furthermore, if the content of particles for adjusting brightness in the present invention exceeds 80% of the present invention, the brittleness of the film may worsen and become brittle.

[0089] The content of particles (inorganic pigments) for adjusting brightness in the film according to the present invention was measured as follows. First, five cross-sections (3 μm × 3 μm) near the surface of the film according to the present invention were cut out and magnified 100,000 times using transmission electron microscopy (TEM). If the particles were large, five cross-sections (10 μm × 10 μm) were cut out and magnified 30,000 times using transmission electron microscopy (TEM). Next, the content of particles (inorganic pigments) for adjusting brightness was analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area was calculated. Finally, the content of particles (inorganic pigments) for adjusting brightness in the film according to the present invention was calculated from the average value of the five locations.

[0090] If the particles used to adjust brightness (inorganic pigments) are titanium dioxide particles with a silica-coated surface, then, based on the surface analysis described above, if silica is attached (coated) to a portion of the titanium dioxide particles, it is considered to be titania with a silica-coated surface.

[0091] (Silica particles) The silica particle content is preferably between 1% and 10% of the surface area. If the silica particle content is less than 1% of the surface area, it may not be able to fill the minute defects in the silica coating on the titanium oxide particles whose surfaces are coated with silica, which may worsen discoloration in an oxygen-free atmosphere. Also, if the silica particle content exceeds 10% of the surface area, the haze of the coating film may worsen, which may worsen the reflectivity.

[0092] The silica particle content in the film according to the present invention was measured as follows: First, five cross-sections (3 μm × 3 μm) near the surface of the film according to the present invention were cut out and magnified 100,000 times using a transmission electron microscope (TEM). If the particles were large, five cross-sections (10 μm × 10 μm) were cut out and magnified 30,000 times using a transmission electron microscope (TEM). Next, the silica particles were analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area was calculated. Finally, the silica particle content was calculated from the average value of the five locations.

[0093] (Other additives) The film according to the present invention may contain other optional additives. Examples include dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, matting agents, preservatives, ultraviolet absorbers, antioxidants, coupling agents, and inorganic and organic fine particles for adjusting the color other than those mentioned above.

[0094] Next, the properties of articles having a film formed in this manner will be described.

[0095] (Solar reflectance) Preferably, at least the portion of the article of the present invention on which the film according to the present invention is formed has a solar reflectance of 60% or more. If the solar reflectance is less than 60%, the temperature reduction effect will decrease.

[0096] (brightness) The portion of the article of the present invention on which the film according to the present invention is formed preferably has a brightness of 50 or higher, and more preferably 71 to 80. If the brightness is less than 50, the reflectance decreases and the temperature reduction effect decreases. If the brightness is 80 or higher, the color becomes white, which may worsen the stain resistance.

[0097] (range of a*, b*) Preferably, a* and b*, which represent the color of at least the portion of the article of the present invention on which the film according to the present invention is formed, are both between -5 and +5. If the values ​​of a* and b* are less than -5 or greater than +5, there is a risk that the color change of a* and b* will be large when the azo organic pigment fades due to irradiation with sunlight.

[0098] [Examples 1-12] The following describes preferred embodiments of the present invention.

[0099] The preparation of the coatings, the fabrication of the films, and the characterization of the articles having the films in Examples 1 to 12 were carried out by the following methods.

[0100] <Evaluation of product characteristics> For characterizing articles with films, a colorimeter (SE-7700; Nippon Denshoku) was used to measure lightness (L*), a*, and b*. For the measurement samples, a 30mm square metal plate with a thickness of 1mm was used, on which the film according to the present invention was formed. The metal plate was made from stainless steel, aluminum, titanium, or magnesium alloy. A magnesium alloy metal plate was also coated with the film according to the present invention to a thickness of 50μm using a spin coater and then fired. After firing, the L*, a*, and b* values ​​of the film portion of the metal plate with the film according to the present invention were measured using a colorimeter. Next, a lightfastness tester (SUNTESTXXL+; ATLAS) was used to measure the radiant intensity at 300nm to 400nm, which was 50±2W / m². 2 The black panel was subjected to a temperature of 63°C ± 3°C for 200 hours. After the lightfastness test was completed, the L*, a*, and b* values ​​of the film portion of the metal plate having the film according to the present invention were measured. ΔL* = L* after lightfastness test - L* after lightfastness test A film with a brightness change (ΔL*) of less than 0.3 is considered a good film with very little color change. A film with a brightness change of 0.3 or more but less than 1.0 is considered a good film. A film with a brightness change of 1.0 or more has a large color change and is not considered a good film.

[0101] (Rated on a 4-point scale from A to C) A; Brightness change ±0.3 is less than 0.3 B; Brightness change ±0.3 or more and less than 1.0 C; Brightness change ±1.0 or greater

[0102] <Solar reflectance evaluation> The evaluation of solar reflectance is described below. Solar reflectance was calculated by first measuring the reflectance using a spectrophotometer (U-4000, Hitachi High-Tech) as shown in Figure 5, and then converting it to solar reflectance.

[0103] First, the reflectance measurement method will be explained. As shown in Figure 5, incident light 1 with a wavelength from 300 nm to 2500 nm was incident on the integrating sphere 19. First, a test piece tilted 5° relative to the incident light 1 was placed in the mounting part 20 with a blank of alumina sintered body that exhibits 100% reflection, and baseline measurement was performed. Next, a test piece with the film according to the present invention was placed in place of the blank in the test piece mounting part 20, and light with a wavelength from 300 nm to 2500 nm was incident on it, and the reflectance was measured by detection with the detector 21. Then, the measured reflectance was multiplied by a weighting value (weight coefficient) based on JIS-K560 (Method for determining the solar reflectance of a coating film), integrated, and the solar reflectance was calculated from the integrated value.

[0104] For the measurement samples, a metal plate measuring 30 mm square and 1 mm thick was used, on which the film according to the present invention was formed. The metal plate was made from stainless steel, aluminum, titanium, or magnesium alloy. A magnesium alloy metal plate was coated with the film according to the present invention to a thickness of 50 μm using a spin coater and then fired. Cellophane tape (CT-12M; Nichiban) was attached to the upper surface of the film according to the present invention. Then, using a lightfastness tester (SUNTESTXXL+; ATLAS), the radiant intensity at 300 nm to 400 nm was measured to be 50 ± 2 W / m². 2 The black panel was subjected to a 200-hour exposure at a temperature of 63°C ± 3°C. After the lightfastness test, the cellophane tape was removed from the film and the panel was cleaned with acetone. Within 24 hours, the reflectance from 300 mm to 2500 nm was measured using a spectrophotometer, and the solar reflectance was calculated based on JIS K 560.

[0105] In terms of solar reflectance, a solar reflectance of 70% or higher indicates a high temperature reduction effect and can be considered a very good film. Furthermore, a solar reflectance of 60% to less than 70% indicates a relatively high temperature reduction effect and can be considered a good film. A solar reflectance below 60% indicates a decrease in temperature reduction effect and cannot be considered a good film.

[0106] (3-level rating from A to C) A: Solar reflectance of 70% or more B: Solar reflectance is between 60% and less than 70% C: Solar reflectance is less than 60%

[0107] <Heat shielding effect> Figure 6 is a schematic diagram showing the temperature evaluation method. As shown in Figure 6, a lamp 22, a temperature measuring jig 25, and a test piece 23 for temperature evaluation were used for temperature measurement. For the test piece 23 for temperature evaluation, a film according to the present invention was formed on a metal plate that was 100 mm square and 1 mm thick. The metal plate was made of stainless steel, aluminum, titanium, or magnesium alloy. The film according to the present invention was applied to the metal plate using a spin coater to a thickness of 50 μm and then fired. For the temperature measuring jig 25, a 120 mm × 120 mm × 120 mm corrugated cardboard with a self-colored surface was used, and a 90 mm × 90 mm window was provided in the mounting area for the test piece 23 for temperature evaluation. A Hilux MT150FD6500K (Iwasaki Electric) lamp 22 was used.

[0108] Next, a test piece 23 for temperature evaluation was attached to the temperature measuring jig 25, and a thermocouple was attached to the back surface of the test piece 23. The temperature measuring jig 25 with the test piece 23 attached was positioned so that the distance to the lamp 22 was 100 mm. Then, the lamp 22 was irradiated for 60 minutes, and the temperature was measured after 60 minutes.

[0109] The temperature reduction effect was determined by forming a black blank on the surface of a test piece 23 for temperature evaluation, measuring the temperature, and calculating the difference between that and the temperature measurement result of the film in the example.

[0110] For the black blank, a mixture of 20g of carbon black (MA100, Mitsubishi Chemical), 100g of epoxy resin (jER828, Mitsubishi Chemical), 70g of amine curing agent (STII, Mitsubishi Chemical), and 20g of thinner was applied to the surface of test piece 23 using a planetary rotating device. The blank was then fired to produce the test piece.

[0111] A film can be considered to have very high heat-shielding properties if its temperature reduction effect is 7°C or more. A film can be considered to have relatively high heat-shielding properties if its temperature reduction effect is between 3°C and 7°C. Conversely, a film cannot be considered to have good heat-shielding properties if its temperature reduction effect is less than 3°C.

[0112] (3-level rating from A to C) A: Temperature reduction effect of 7°C or more B: Temperature reduction effect is 3°C or more but less than 7°C C: Temperature reduction effect is less than 5°C

[0113] [Example 1] <Preparation of paint> In Example 1, the paint was prepared by the following method. 125 g of resin (48.6 vol% in terms of paint film), 0.5 g of azo organic particles (0.2 vol% in terms of paint film), and 4.5 g of particles containing Ti and O (0.7 vol% in terms of paint film) were weighed. In addition, 150 g of particles for adjusting brightness (inorganic pigment) (28.6 vol% in terms of paint film), 5 g of dispersant (3.5 vol% in terms of paint film), and 100 g of solvent were weighed. The mixture was then stirred in a ball mill for 15 hours to obtain the main component. 1 g of hardener (18.4 vol% in terms of volume) was mixed with 10 g of the obtained main component to obtain the paint of Example 1.

[0114] For the resin, we used Olestar Q-691 (Mitsui Chemicals). For the azo organic particles, we used Chromofine Black A1103 (Dainichi Seika Kogyo). For the particles containing Ti and O, we used #5950 (Asahi Sangyo). For the particles used to adjust brightness (inorganic pigment), we used D-970 (Sakai Chemical; average particle size 0.26 μm, silica-coated titania). For the curing agent, we used Takenate D-120N (Mitsui Chemicals).

[0115] <Membrane fabrication> In Example 1, the film was prepared by the following method. The above-mentioned paint was applied to a magnesium alloy metal plate using a spin coater to create a film of the present invention with a thickness of 50 μm. After drying overnight at room temperature, it was baked at 130°C for 30 minutes to obtain the film of Example 1.

[0116] [Examples 2-13] In Examples 2 to 13, the paints and films were prepared in the same manner as in Example 1, except that the materials and conditions were as shown in Tables 1 and 2.

[0117] Furthermore, Yellow5000 (Asahi Sangyo) was used for (Ti,Ni,Sb)O2 particles. Sphericel-110P8 (Potters Balotini) was used for hollow silica. CI Pigment Yellow 150 was used for nickel azo particles. Brown4123 (Asahi Sangyo) was used for Fe-Zn particles. Green2024 (Asahi Sangyo) was used for Co-Al-Ni-Ti particles. CoBlue1024 (Asahi Sangyo) was used for Co-Al particles. HT0110 (Toho Titanium) was used for TiO2 particles.

[0118] [Table 1]

[0119] [Table 2]

[0120] (Evaluation results) Tables 3 and 4 show the results of evaluating the change in brightness (ΔL*), solar reflectance (R) after the lightfastness test, and temperature reduction effect before and after the lightfastness test for films of Examples 1 to 12 using the method described above.

[0121] The results were evaluated based on whether the change in brightness (ΔL*) was kept below 1.0, more preferably below 0.3, despite the presence of azo-based organic particles.

[0122] Furthermore, regarding the heat shielding effect, it was stated that a solar reflectance of 60% or more and less than 70% is preferable, and a solar reflectance of 70% or more is more preferable. In addition, the temperature reduction effect was stated to be preferably 3°C or more and less than 7°C, and more preferably 7°C or more.

[0123] As shown in Table 3, the change in brightness, solar reflectance, and temperature reduction effect after a lightfastness test of Example 1, which was prepared using acrylic polyol, azomethine black, (Ti, Sb, Cr)O2, silica-coated titania, and a dispersant to adjust the brightness to 76, were evaluated. The change in brightness was less than 0.3, which was very good. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0124] Table 3 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Example 2, which was adjusted to contain less azomethine black (0.1 vol%) and less (Ti, Sb, Cr)O2 (0.1 vol%) compared to Example 1. The brightness change was less than 0.3, which was very good. The solar reflectance was also very good at over 70%. The temperature reduction effect was also very good at over 7°C.

[0125] Table 3 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Example 3, which was adjusted to contain 0.4 volume% azomethine black and 1 volume% (Ti, Sb, Cr)O2 compared to Example 1. The brightness change was less than 0.3, which was very good. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0126] Table 3 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film in Example 4, which used (Ti, Ni-Sb)O2 instead of (Ti, Sb, Cr)O2 compared to Example 1. The brightness change was less than 0.3, which was very good. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0127] Table 3 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film in Example 5, which used insulating hollow silica instead of silica-coated titanium oxide compared to Example 1. The brightness change was less than 0.3, which was very good. Although the solar reflectance was less than 60%, the temperature reduction effect was between 3°C and 7°C due to the high insulating effect of hollow silica, which was also good.

[0128] Table 3 shows the changes in brightness, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film in Example 6, which used nickel azo instead of azomethine black compared to Example 1. The change in brightness was less than 0.3, which was very good. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0129] Table 4 shows the changes in brightness, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Example 7, in which Fe-Zn particles were added as another pigment to Example 1 and a* was adjusted to +6. The change in brightness was between 0.3 and less than 1.0, which was good. The solar reflectance was between 60% and less than 70%, which was also good. The temperature reduction effect was between 3°C and less than 7°C, which was also good.

[0130] Table 4 shows the brightness change, solar reflectance, and temperature reduction effect of the film of Example 8, which was prepared by adding 0.2 volume% of (Co-Al-Ni-Ti)O2 to the film of Example 1 and adjusting a* to -6, before and after the lightfastness test. The brightness change was between 0.3 and less than 1.0, which was good. The solar reflectance was between 60% and less than 70%, which was also good. The temperature reduction effect was between 3°C and less than 7°C, which was also good.

[0131] Table 4 shows the brightness change, solar reflectance, and temperature reduction effect of the film of Example 9, which was prepared by adding a larger amount of (Ti, Sb, Cr)O2 (1.63 vol%) compared to Example 1, and adjusting the b* to +6, before and after the lightfastness test. The brightness change was between 0.3 and less than 1.0, which was good. The solar reflectance was between 60% and less than 70%, which was also good. The temperature reduction effect was between 3°C and less than 7°C, which was also good.

[0132] Table 4 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Example 10, in which Co-Al was added to Example 1 to adjust b* to -6. The brightness change was between 0.3 and less than 1.0, which was good. The solar reflectance was between 60% and less than 70%, which was also good. The temperature reduction effect was between 3°C and less than 7°C, which was also good.

[0133] Table 4 shows the changes in brightness, solar reflectance, and temperature reduction effect of the film of Example 11, in which titania was added instead of (Ti, Sb, Cr)O2 compared to Example 1, before and after the lightfastness test. The change in brightness was between 0.3 and less than 1.0, which was good. The solar reflectance was between 60% and less than 70%, which was also good. The temperature reduction effect was between 3°C and less than 7°C, which was also good.

[0134] Table 4 shows the changes in brightness, solar reflectance, and temperature reduction effect of the film of Example 12, which was prepared by adding 0.94 volume% azomethine black and 1.61 volume% (Ti, Sb, Cr)O2 to Example 1 to adjust the brightness to 50. The changes in brightness were less than 0.3, which was very good. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0135] Table 4 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Example 13, which had higher additions of azomethine black (1.11 vol%) and (Ti, Sb, Cr)O2 (1.6 vol%) compared to Example 1. The brightness change was less than 0.3, which was very good. However, because the brightness became too low, the solar reflectance was low, less than 60%. Also, the temperature reduction effect was poor, less than 3°C. From this, it was found that even with a film containing a large amount of azomethine black, the brightness change can be suppressed by including particles containing Ti and O. However, since adding a large amount of azomethine black lowers the brightness, reduces the solar reflectance, and suppresses the temperature reduction effect, it was found that it is preferable to adjust the brightness to 50 or higher.

[0136] [Table 3]

[0137] [Table 4]

[0138] [Comparative Examples 1-2] The preparation of paints for comparison, film fabrication, evaluation of film properties, evaluation of brightness change, evaluation of solar reflectance, and evaluation of temperature reduction effect were carried out in the same manner as in Examples 1 to 13 described above. The differences from Examples 1 to 13 are shown below.

[0139] Table 5 shows the materials and amounts added to the films of Comparative Examples 1 and 2. Table 6 shows the evaluation results using the films of Comparative Examples 1 and 2.

[0140] Table 5 shows the brightness change, solar reflectance, and temperature reduction effect of the film of Comparative Example 1, in which Fe-Cr (Black6350; Asahi Sangyo) was added instead of azomethine black compared to Example 1, before and after the lightfastness test. Because it did not contain azo organic particles, the brightness change was kept to less than 0.3, but the solar reflectance was low at less than 60%. The temperature reduction effect was also poor, at less than 3°C.

[0141] Table 5 shows the brightness change, solar reflectance, and temperature reduction effect before and after the lightfastness test of the film of Comparative Example 2, which did not contain (Ti, Sb, Cr)O2, compared to Example 1. The brightness change was 1.0 or higher, which was poor. The solar reflectance was between 60% and 70%, which was good. The temperature reduction effect was between 3°C and 7°C, which was also good.

[0142] [Table 5]

[0143] [Table 6]

[0144] (Second embodiment) As an example of an embodiment of the present invention, an article having a film with excellent heat-shielding and water-resistant properties will be described with reference to Figure 7. Parts that are the same as those in the first embodiment may be omitted from the description.

[0145] 《Material Composition》 Figure 7 shows an article having a film 122 formed on at least a portion of the surface 121 of a substrate 120, where Figure 7(a) is a cross-sectional view of the article of this embodiment. Figure 7(b) is an enlarged schematic view of region 125 in Figure 7(a). Figure 7(c) is an explanatory diagram of aggregated silica particles. Figure 7(d) is an SEM image of a cross-section of the article. Figure 7(d) shows an example in which the substrate 120 includes a primer layer. In Figure 7, the article of this embodiment has a substrate 120 and a film 122, and the film 122 includes at least a resin 126 and particles 127 with an average particle size of 100 nm to 400 nm. Furthermore, the film 122 of this embodiment includes a region 124 containing particles 127 with an average particle size of 100 nm to 400 nm and a region 123 that does not contain particles 127 with an average particle size of 100 nm to 400 nm. In this specification, the region containing particles 127 with an average particle size of 100 nm or more and 400 nm or less is referred to as the particle region 124, and the region not containing particles 127 with an average particle size of 100 nm or more and 400 nm or less is referred to as the resin region 123.

[0146] (resin) Next, the resin 126 included in the film 122 of this embodiment will be described.

[0147] Examples of resins used in this embodiment include epoxy resin, urethane resin, acrylic resin, urethane-acrylic resin, phenolic resin, and alkyd resin. These resins may be used individually or in combination of multiple types.

[0148] Furthermore, the resin content of the resin 126 in this embodiment is preferably 10% to 80% in the cross-section of the film, and more preferably 15% to 70% in the cross-section. In this specification, the cross-section of the film is defined as a cross-section cut out from the surface 121 of the substrate 120 or the surface 30 of the film 122, parallel to the normal direction, with an area of ​​at least 30 μm × 30 μm. A cross-section parallel to the normal direction is preferred, but a cross-section inclined at about 10° with respect to the normal direction is also acceptable. In addition, if the film thickness is 30 μm or less, a cross-section with sides of 30 μm or less is also acceptable.

[0149] If the resin 126 content in this embodiment is less than 10 area percent, the adhesion to the substrate 120 may deteriorate. Also, if the resin 126 content in this embodiment exceeds 80 area percent, the solar reflectance may deteriorate. The resin 126 content in this embodiment is measured as follows. First, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film 122 according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the resin is analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area is calculated. Finally, the resin 126 content in the film 122 according to the present invention is calculated from the average value of the five locations. In this embodiment, the content calculated by this method is expressed as area percent.

[0150] (White pigment) Next, the white pigment particles 127 (which may be referred to as the first particles or simply particles in this specification) contained in the film 122 of this embodiment will be described. The film 122 of this embodiment preferably has a high solar reflectance, is white, and has a high refractive index. By including particles 127 in the film 122, it is possible to obtain a film 122 that is white and has a high refractive index. The particles 127 are particles containing at least one of titania, alumina, zirconia, and zinc oxide. In particular, it is more preferable to use particles of titania with a high refractive index whose surface is coated with silica, as this can suppress photocatalytic activity and reduce the degradation of the surrounding resin.

[0151] Furthermore, the particle size of particle 127 is preferably such that the average particle size is between 100 nm and 400 nm. If the average particle size is less than 100 nm, it is difficult to reflect sunlight. Also, if the average particle size exceeds 400 nm, the water resistance decreases. As will be described in detail later, due to the difference in hydrophilicity between resin 126 and particle 127, moisture is incorporated into the film through the interface between resin 126 and particle 127. If the average particle size exceeds 400 nm, the continuous contact area with resin 126 increases further, and a very large amount of moisture is incorporated into a part of the film, resulting in a significant decrease in water resistance. The particle size of particle 127 according to this embodiment is determined as follows. First, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film 122 according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the particles 127 are analyzed at five locations using Energy Dispersive X-ray Spectroscopy (EDS) to determine the particle diameter of each individual particle and calculate its average value. Finally, the average of the five locations is calculated. This average of the five locations is taken as the average particle diameter of the particles 127 contained in the film according to this embodiment.

[0152] The particle content 127 in this embodiment is preferably 10% to 60% in the cross-section of the film 122 according to this embodiment, and more preferably 15% to 50%. If the particle content 127 is less than 10% in the cross-section, the opacity to sunlight decreases, and the film ceases to function as a film with excellent heat shielding performance. Furthermore, if the particle content 127 in this embodiment exceeds 90% in the cross-section, the brittleness of the film deteriorates, and it may become brittle. The particle content 127 is measured as follows. First, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the particles at the five locations are analyzed using Energy Dispersive X-ray Spectroscopy (EDS), and the content per unit area is calculated. Finally, the particle content 127 contained in the film 122 according to the present invention is calculated from the average value of the five locations. In this embodiment, the content calculated by this method is expressed as area %.

[0153] (Silica particles) The film 122 of this embodiment may contain silica particles 128. The silica particles 128 preferably have an average particle diameter of 50 nm to 350 nm, and more preferably 150 nm to 300 nm, based on the number of particles. If the average particle diameter of the silica particles 128 is less than 50 nm, the thixotropy of the coating for forming the film decreases, and the coatability deteriorates. Furthermore, the shape of these fine particles may be, for example, a perfect sphere, a spherical shape, an ellipsoid, a rectangular parallelepiped, a cube, a combination thereof, or an amorphous shape.

[0154] In this embodiment, the particle diameter of the silica particles 128 is the average particle diameter based on the number of particles. The average particle diameter of the silica particles 128 can be measured by dynamic light scattering when the paint is in its pre-coating state. When measuring from the state of the film, first, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the silica particles 128 are analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) to determine the particle diameter of each silica particle 128 and calculate its average value. Finally, the average value of the five locations is calculated. This average value of the five locations is taken as the average particle diameter of the silica particles contained in the film according to this embodiment. In this embodiment, for example, as shown in Figure 7(c), if silica particles 128 between 10 nm and 50 nm aggregate to form secondary particles, the coatability can be improved if the longitudinal length of the secondary particles is between 50 nm and 350 nm. In particular, it is preferable to select chain-like silica particles in which spherical silica particles 128 are linked together. Chain-like silica particles in which spherical silica particles 128 are linked together are preferable because when applying a coating for forming a light-shielding film, the space created by the silica particles 128 is large, making it easier for the particles 127 to move.

[0155] Furthermore, the silica particle 128 content is preferably 2.5 area% to 15.0 area% in the cross-section of the film according to this embodiment, and more preferably 2.5 area% to 10.0 area%. If the silica particle 128 content is less than 2.5 area%, the thixotropy of the paint decreases, and the coatability deteriorates. Also, if the silica particle 128 content is greater than 15.0 area%, the heat shielding performance deteriorates. The silica particle 128 content is measured as follows. First, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the silica particle 128 is analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area is calculated. Finally, the silica particle 128 content contained in the film according to the present invention is calculated from the average value of the five locations. In this embodiment, the content calculated by this method is expressed as area %.

[0156] (Coloring agent) The film 122 of this embodiment may contain a pigment other than the white pigment particles 127 mentioned above as a coloring agent, if necessary, to give it an aesthetically pleasing appearance. In this specification, the pigment other than the white pigment may be simply referred to as a pigment.

[0157] The pigment of this embodiment is preferably adjustable so that the brightness (L* value) of the heat-shielding film is 71 or higher, and more preferably in the range of 71 to 85. If the brightness of the heat-shielding film of this embodiment is less than 71, the solar reflectance decreases, and the temperature reduction effect deteriorates. If the brightness of the heat-shielding film of this embodiment exceeds 85, the absorption of visible light by the pigment decreases, so there is a risk of experiencing glare due to the reflection of visible light. Furthermore, the pigment of this embodiment is preferably able to reflect or transmit infrared rays.

[0158] In this embodiment, the pigment refers to a coloring agent, and may be an organic pigment, an inorganic pigment, or a combination thereof.

[0159] In this embodiment, the brightness is defined as the value measured using a colorimeter (SE-7700; Nippon Denshoku).

[0160] Examples of organic pigments include azomethine black and perylene pigments. Examples of inorganic pigments include Co-Zn-Si, Co-Al, Co-Al-Cr, Co-Al-Cr-Zn, Co-Al-Zn-Ti, Co-Ni-Zn-Ti, Ti-Cr-Sb, Ti-Fe-Zn, Fe-Zn, and Fe-Cr. Other examples include Mn-Bi, Co-Cr-Zn-Sb, Cu-Cr, Cu-Cr-Mn, Cu-Fe-Mn, Mn-Y, Mn-Sr, Co-Cr-Zn-Al-Ti, Co-Cr-Zn-Ti, Ti-Cr-Sb, and P-Ba-Sr.

[0161] (Organic pigments) Any particles containing an azo group can be used as the azo organic particles. Examples of azo organic particle colors in this embodiment include black, yellow, red, and orange, but black is preferred because it exhibits less color change (a*, b*) when fading occurs due to sunlight. Furthermore, a high reflectivity to sunlight is preferred, and it is preferable to select a material with a solar reflectance exceeding 10% for the azo organic particles alone. Examples of azo organic particles include nickel azo pigments, insoluble azo pigments, soluble azo pigments, high molecular weight azo pigments, and azomethine azo pigments. These azo organic particles may be used individually or in combination of multiple types.

[0162] The average particle size of the organic pigment in this embodiment is preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.1 μm or more and 2.0 μm or less. If the average particle size of the organic pigment in this embodiment is less than 0.1 μm, the surface area of ​​the particles increases, which can lead to poor light resistance and discoloration. Furthermore, if the average particle size of the organic pigment in this embodiment exceeds 5.0 μm, the unevenness of the film increases, which can lead to poor film thickness accuracy. If this embodiment is used in a lens barrel, it may reduce the accuracy of focusing and other functions.

[0163] In this embodiment, the average particle size is the average of the individual particle sizes of multiple resin particles. The average particle size of the resin particles is determined by dispersing them in water and analyzing them using a laser scattering method. In this embodiment, the average particle size of the resin particles is the volume-average particle size.

[0164] Furthermore, organic pigments can be used in the form of particles of any shape. Examples include spherical, cubic, elliptical, plate-like, layered, chain-like, hollow, star-shaped, needle-like, and irregularly shaped particles. Among these, plate-like, layered, and chain-like shapes are particularly preferred as they are more likely to cause segregation towards the air interface due to aggregation of the organic pigment.

[0165] These organic pigments may be used individually or in combination of multiple types, but it is preferable to use them in a manner that does not impair the aesthetic appearance or heat-shielding properties.

[0166] Furthermore, the content of the organic pigment in the paint according to this embodiment is preferably 0.01% by weight or more and 1.0% by weight or less, and more preferably 0.015% by weight or more and 0.5% by weight or less, when the total weight of the paint is 100% by weight. If the content of the organic pigment is less than 0.01% by weight, the brightness of the film becomes too high, which deteriorates the aesthetic appeal. There is also a risk that the stain resistance will deteriorate. On the other hand, if the content of the organic pigment is 1.0% by weight or more, the brightness of the film becomes too low, which deteriorates the heat shielding properties.

[0167] (Inorganic pigments) Any inorganic pigment with excellent heat-shielding properties can be used as the inorganic pigment in this embodiment, but it is preferable to include titania particles whose surface is coated with silica. It is preferable to further include colored inorganic pigment for color adjustment. It may also include particles containing Ti and O whose surface is not coated. The particles containing Ti and O whose surface is not coated may be colored inorganic pigment. In this embodiment, particles containing Ti and O whose surface is not coated may simply be referred to as particles containing Ti and O.

[0168] Titania has a high refractive index, making it easy to adjust the film to the desired refractive index. Furthermore, its light color makes it easy to adjust the coating to the desired hue. Additionally, it can be suitably used because a large number of sufficiently finely atomized particles are readily available and relatively inexpensive.

[0169] In this embodiment, the content of silica-coated titania particles in the film is preferably 10% to 70% by weight relative to the resin composition, and more preferably 20% to 60% by weight. If the content is less than 10% by weight, a sufficient infrared reflection effect may not be obtained, and if it is more than 70% by weight, a film with sufficient quality may not be obtained. By using silica-coated particles, photocatalytic activity can be suppressed, thereby reducing the degradation of the surrounding resin.

[0170] Furthermore, the average particle diameter of the silica-coated titania particles in this embodiment is preferably 0.1 μm or more and 1.5 μm or less, and more preferably 0.1 μm or more and 1.0 μm or less. If it is less than 0.1 μm, the surface area of ​​the particles increases, making the silica-coated titania particles more prone to aggregation, and making it difficult to disperse them appropriately in the film. Also, if it is greater than 1.5 μm, as will be described in detail later, it inhibits the segregation of the organic pigment toward the air interface, and it becomes impossible to achieve sufficient performance to balance design and heat shielding properties. In this embodiment, silica-coated titania particles are defined as those in which at least a part of the surface is covered with silica. Furthermore, the average particle diameter of silica-coated titania particles in this embodiment refers to the volume sphere equivalent diameter of unaggregated particles.

[0171] The titania particles coated with silica on the surface in this embodiment can be manufactured by known methods such as gas-phase or liquid-phase methods, as long as their refractive index and average particle size satisfy the desired conditions. For example, known methods include a method of synthesizing titanium dioxide nanoparticles by introducing metal powder into a flame and burning it in an atmosphere containing at least oxygen, and a sol-gel method in which titanium alkoxide is hydrolyzed and polycondensed in the presence of a catalyst. Furthermore, titania is known to have crystalline structures such as rutile and anatase structures, which exhibit a higher refractive index compared to amorphous structures, but any crystalline form can be suitably used as long as it satisfies the desired particle size.

[0172] The inorganic pigment according to this embodiment may contain a colored inorganic pigment in addition to the titania particles whose surface is coated with silica as described above. The content of the infrared-reflective colored inorganic pigment in this embodiment is preferably 0.01% by weight or more and 2.0% by weight or less, and more preferably 0.02% by weight or more and 1.5% by weight or less. If the content of the infrared-reflective colored inorganic pigment in this embodiment is less than 0.01% by weight, the photocatalytic effect when irradiated with sunlight will be small, which may cause a large change in the appearance color of the film of this embodiment. If the content of the infrared-reflective colored inorganic pigment in this embodiment exceeds 2.0% by weight, the heat shielding performance may deteriorate. Furthermore, it is more preferable that the infrared-reflective colored inorganic pigment in this embodiment is uniformly dispersed in the film.

[0173] Furthermore, the material may also contain uncoated Ti and O particles. Since the Ti and O particles need to cleave the resin's molecular chains through photocatalysis, it is preferable that there is little to no coating of light-resistant silica or similar material. This is because we want the photocatalytic action of the uncoated Ti and O particles to cause the film's brightness to decrease when irradiated with sunlight. The reason for this will be explained below. The azo-based organic particles mentioned above as organic pigments are colored pigments that have an azo group, RN=NR', in their molecules. Azo-based organic particles have the characteristic of having higher infrared reflection performance compared to inorganic pigments, but when irradiated with sunlight, the azo group in azo-based organic particles is cleaved into 2R and N2. Since azo-based organic particles exhibit color due to the N=N group and the surrounding atomic arrangement contained within the azo-based organic particles, when N=N is cleaved, the color disappears and the brightness increases. In other words, the color of the film formed on the surface of an object such as an optical instrument may change significantly. This change is more pronounced the smaller the amount of azo-based organic particles.

[0174] On the other hand, in particles 10 containing Ti and O, the TiO2 portion within the particles is excited by the photocatalytic action of sunlight, becoming excited particles containing Ti and O. These Ti and O particles, excited by sunlight, release electrons (e-) into the resin, and the molecular chains of the resin are broken by the electron energy. As a result, the resin becomes discolored and its brightness decreases.

[0175] Thus, in the film according to the present invention, when irradiated with sunlight, the brightness of the azo organic particles changes to a high degree, while the brightness of the particles containing Ti and O changes to a low degree, so overall, color change is suppressed by a cancellation effect. The particles containing Ti and O include particles containing only Ti and O (e.g., titania particles), and / or particles containing one or more inorganic metals in addition to Ti and O. Examples of particles containing one or more inorganic metals in addition to Ti and O in this embodiment include (Ti, Ni, Sb)Ox and (Ti, Cr, Sb)Ox. Also, examples include (Ti, Fe, Zn)Ox, (Co, Cr, Zn, Al, Ti)Ox, (Co, Cr, Zn, Ti)Ox, (Co, Al, Ni, Ti)Ox, etc. Furthermore, examples of particles containing Ti and O in the present invention include the above-mentioned (Ti, Ni, Sb)Ox, (Ti, Cr, Sb)Ox, and (Ti, Fe, Zn)Ox. Other examples include (Co, Cr, Zn, Al, Ti)Ox, (Co, Cr, Zn, Ti)Ox, and (Co, Al, Ni, Ti)Ox. If particles containing Ti and O are included, their content is preferably 1.6% by weight or less.

[0176] Any color pigment can be used as the pigment in this embodiment. Examples include black, brown, yellow, red, blue, purple, pink, green, and orange. One type of pigment or a combination of several types may be used.

[0177] In this embodiment, the pigment content is preferably 15 area percent or less in the cross-section of the film according to this embodiment. If the pigment content of the present invention exceeds 15 area percent, the color of the coating film may become darker and the brightness may decrease. The pigment content is measured as follows. First, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the pigment is analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) and the content per unit area is calculated. Finally, the pigment content contained in the film according to the present invention is calculated from the average value of the five locations. In this embodiment, the content calculated by this method is expressed as area percent.

[0178] (Other additives) The film used in the optical instrument of the present invention may contain other optional additives. Examples include dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, matting agents, preservatives, ultraviolet absorbers, antioxidants, coupling agents, and inorganic and organic fine particles for adjusting the color other than those mentioned above.

[0179] Next, we will explain methods for improving water resistance while maintaining the heat-shielding effect of the heat-shielding film.

[0180] [Methods for improving water resistance while maintaining the heat-shielding effect of a heat-shielding film] (Regarding the water resistance of the heat-shielding film) A film 122 containing resin 126 and particles 127 with an average particle size of 100 nm to 400 nm absorbs moisture from the film surface into the interior of the film under rainy weather conditions or high humidity. This was found to be due to the difference in hydrophilicity between resin 126 and particles 127, which allows moisture to be absorbed into the film through the interface between resin 126 and particles 127. The moisture absorbed through the interface between resin 126 and particles 127 is increasingly absorbed into the film and becomes unevenly distributed at the interface 129 between film 122 and substrate 120. In the presence of this moisture, expansion and contraction occur in film 122 and substrate 120 due to temperature changes. As a result, due to the difference in expansion coefficients between film 122 and substrate 120, defects such as film lifting and peeling at the interface 129 between film 122 and substrate 120, and blistering due to the reaction between substrate 120 and moisture occur. On the other hand, in order to achieve high heat shielding properties, it is desirable to increase the content of particles 127 with an average particle size of 100 nm to 400 nm in the film as much as possible. However, this increases the number of pathways for moisture in the film, and increases the amount of moisture at the interface 129 between the film 122 and the substrate 120.

[0181] (A method for improving water resistance while maintaining the heat-shielding effect of the heat-shielding film of the present invention) Thus, it became clear that improving both heat shielding and water resistance is a challenge that cannot be achieved simultaneously with conventional technologies.

[0182] The inventors diligently investigated methods to maintain heat shielding properties and improve water resistance, and discovered that a resin region 123, which does not contain particles 127 and has an average particle size of 100 nm to 400 nm, is provided in the film 122, separating the interface between the resin 126 and the particles 127. Specifically, a resin region 123, which does not contain particles 127 and has an average particle size of 100 nm to 400 nm, is provided between regions containing particles 127 (particle regions 124). This has been found to make it possible to improve water resistance while maintaining heat shielding properties.

[0183] (Resin area) This embodiment will describe the region 123 (resin region) that does not contain particles 127 with an average particle size of 100 nm or more and 400 nm or less.

[0184] As shown in Figure 7, the resin region 123 is a region that includes at least resin 126 and optionally the aforementioned additives. Examples of resin 126 include epoxy resin, urethane resin, acrylic resin, urethane acrylic resin, phenolic resin, and alkyd resin.

[0185] The refractive index of the resin region is preferably lower than that of the particle region. When the refractive index of the resin region is lower than that of the particle region, sunlight reflection can be achieved more efficiently, and the heat shielding performance can be improved.

[0186] To achieve a low refractive index, a resin with low refractive index properties can be used, or particles with low refractive index properties can be used.

[0187] Resins having a low refractive index are preferably those with a refractive index of 1.6 or less, and examples include silicone-based resins, fluororesins, and resins into which fluorine groups have been introduced. Examples of silicone-based resins include methyl-based, methyl / phenyl-based, propyl / phenyl-based, epoxy-resin modified, alkyd-resin modified, polyester-resin modified, rubber-based, and their resins and oligomers. One type of these resin may be used, or multiple types may be included.

[0188] Furthermore, the refractive index of the resin region can be lowered by dispersing particles with a particle size smaller than 100 nm and a refractive index of 1.6 or less (referred to as low refractive index particles) in the resin. Alternatively, low refractive index particles can be dispersed in a resin that already possesses low refractive index properties.

[0189] Low refractive index particles can be organic or inorganic. Examples of materials include particles containing at least one of fluorine, MgF2, and silica. The shape can be spherical, amorphous, hollow, or porous.

[0190] Furthermore, the content of the resin having the low refractive index characteristic of this embodiment is preferably 20% by volume or more and 100% by volume or less, and more preferably 30% by volume or more and 90% by volume or less. If the content of the resin of this invention is less than 20% by volume, the adhesion between the resin region 123 and the adjacent particle region 124 may deteriorate. Similarly, if the content of the resin having the low refractive index characteristic of this embodiment exceeds 90% by volume, the adhesion between the resin region 123 and the adjacent particle region 124 may also deteriorate.

[0191] The shape and area of ​​the resin region 123 can be determined by conventional SEM observation of a cross-section of the film perpendicular to the surface 1220 of the film 122. The SEM observation conditions are assumed to be an acceleration voltage of 5kV and a magnification of 1000x, and the values ​​obtained are those obtained from the observation.

[0192] The width D of the resin region 123 in the direction normal to the surface of the substrate 120 is preferably 200 nm or more and 2000 nm or less, and more preferably 200 nm or more and 1000 nm or less. If the width D of the resin region 123 in the direction normal to the surface of the substrate 120 is less than 200 nm, the effect on water resistance may be lost. Also, if it exceeds 2000 nm, the heat shielding effect may decrease.

[0193] The width E of the resin region 123 in the direction parallel to the surface of the substrate 120 (parallel direction) is preferably 3 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less. If it is less than 3 μm, the effect on water resistance may be lost, and if it exceeds 100 μm, defects such as film peeling may occur.

[0194] The total area of ​​the resin regions 123 distributed within the film 122 is preferably between 0.05% and 13% of the total cross-sectional area of ​​the film, and more preferably between 0.1% and 5%. If it is less than 0.05% of the total cross-sectional area of ​​the film, the effect on water resistance may be lost. If it exceeds 13% of the total cross-sectional area, the heat shielding performance may deteriorate significantly.

[0195] 《Membrane composition》 The film formed on the upper surface of the article in this embodiment, particularly an optical instrument, is formed at least outside the substrate. Its form may be in close contact with the substrate, or a primer layer may be provided between the substrate and the film formed on the upper surface of the optical instrument to improve adhesion. Furthermore, if a metal is used as the substrate, a chemical conversion treatment may be applied as necessary.

[0196] (base material) Any material can be used as the base material, but metals and plastics are preferred. Examples of metal materials include aluminum, titanium, stainless steel, magnesium alloys, and lithium-magnesium alloys. Examples of plastics include polycarbonate resin, acrylic resin, ABS resin, and fluororesin.

[0197] Furthermore, while the film thickness of the substrate can be any thickness, it is preferably 0.5 mm to 5 mm, and more preferably 0.5 mm to 2 mm. If the film thickness is less than 0.5 mm, it becomes difficult to maintain the shape of the lens barrel. Also, if the film thickness exceeds 5 mm, the cost of the component increases.

[0198] (Primer) Primers may also be used to improve the adhesion between the substrate and the film.

[0199] Any material can be used as the primer, but examples include epoxy resin, urethane resin, acrylic resin, silicone resin, and fluororesin. The primer may also contain particles of the present invention or other particles, colorants, dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, organic colorants, inorganic colorants, preservatives, UV absorbers, antioxidants, coupling agents, and solvent residues.

[0200] Furthermore, the primer film thickness is preferably 2 μm to 30 μm, and more preferably 5 μm to 20 μm. If the film thickness is less than 2 μm, the adhesion of the film may decrease, and if it exceeds 30 μm, it may adversely affect the positional accuracy.

[0201] (Film thickness of the film in this embodiment) The film in this embodiment preferably has a thickness of 10 μm or more and 70 μm or less. If the film thickness is less than 10 μm, the solar reflectance may decrease. If the film thickness exceeds 70 μm, the center may be off-center when assembled with other components, which may adversely affect the positional accuracy of optical equipment.

[0202] Method for manufacturing the article according to this embodiment (Method of forming a membrane) The film of the article in this embodiment is 10 μm or more and 70 μm or less in thickness. Any application method and effect method can be used as long as the heat-shielding coating of this embodiment can be applied uniformly.

[0203] Examples of coating methods for articles of this embodiment, particularly films for optical instruments, include brush coating, spray coating, dip coating, transfer, and inkjet printing. The film may be a single-layer coating or a multi-layer coating, and may also be textured to enhance its aesthetic appeal.

[0204] Furthermore, the curing method for the articles of this embodiment, particularly films for optical instruments, may be left at room temperature, or curing may be accelerated by applying heat or ultraviolet light. Examples of methods for curing by applying heat include heating furnaces, heaters, and infrared heating. The curing temperature is preferably from room temperature to 400°C, and more preferably from room temperature to 200°C.

[0205] (Method for forming a resin region) After forming a film (particle region) using the method described above, the material to be used for the resin region can be applied to a portion of the film on the surface of the film (particle region) using a transfer or inkjet method. After forming the resin region, a resin region can be formed inside the film (between the particle regions) by further forming a film (particle region). The resin region can also be formed using photolithography if the substrate is flat. Furthermore, the linear region in the film for optical instruments of the present invention (between the particle regions) may be left at room temperature, or curing may be accelerated by applying heat or ultraviolet light. Methods for curing by applying heat include heating furnaces, heaters, and infrared heating. The curing temperature is preferably from room temperature to 400°C, and more preferably from room temperature to 200°C.

[0206] [Examples 14-27] The following describes preferred embodiments of the present invention.

[0207] The characterization and fabrication of the films in Examples 14 to 27 were performed by the following methods.

[0208] <Evaluation of the water resistance of the heat-shielding film> <Water resistance testing and evaluation> For measuring water resistance, a 30mm square metal plate with a thickness of 1mm was used as a sample, on which the film of this embodiment was formed. The metal plate was made from stainless steel, aluminum, titanium, or magnesium alloy. A magnesium alloy metal plate was also prepared by coating it to a thickness of 65μm using a spin coater and inkjet printer, and then firing it to form the film.

[0209] The heat-shielding film of this embodiment was placed in a constant-temperature chamber set to high temperature and high humidity (temperature: 70°C, humidity: 90%) for 100 hours to examine its water resistance.

[0210] Water resistance was evaluated according to JIS K 5600-5-4 (scratch hardness (pencil method)) by comparing the results before and after the water resistance test. Those with no change in hardness before and after the weathering test were classified as A, and those with a decrease in hardness were classified as B.

[0211] <Solar reflectance evaluation> The solar reflectance was measured and calculated using the same apparatus and method as in the first embodiment.

[0212] For the measurements, a metal plate measuring 30 mm square and 1 mm thick was used, on which a film was formed. The metal plate was made from one of the following materials: stainless steel, aluminum, titanium, or magnesium alloy. Additionally, a magnesium alloy metal plate was coated to a thickness of 65 μm using a spin coater and inkjet printer, and then fired to form the film.

[0213] In terms of solar reflectance, a solar reflectance of 70% or higher indicates a high temperature reduction effect and can be considered a very good film. Furthermore, a solar reflectance of 60% to less than 70% indicates a relatively high temperature reduction effect and can be considered a good film. A solar reflectance below 60% indicates a decrease in temperature reduction effect and cannot be considered a good film.

[0214] (3-level rating from A to C) A: Solar reflectance of 70% or more B: Solar reflectance is between 60% and less than 70% C: Solar reflectance is less than 60%

[0215] <Heat shielding effect> The heat shielding effect was also measured using the same apparatus and method as in the first embodiment.

[0216] [Example 14] <Preparation of paint> In Example 14, a paint was prepared using the following method: 15 g of titanium dioxide (20 vol. equivalent to the paint film), 13 g of resin (57.5 vol. equivalent to the paint film), 0.75 g of silica (1.8 vol. equivalent to the paint film), 1 g of pigment (3.5 vol. equivalent to the paint film), 3.9 g of hardener (17.2 vol. equivalent to the paint film), and 3 g of thinner were used. Each component was weighed and stirred for 10 minutes using a planetary rotating device (AR-100, Sinky) to obtain paint T1 of Example 14. For the titanium dioxide, D-970 (Sakai Chemical; average particle size 0.26 μm, silica surface coating) was used. For the resin, Olestar Q-691 (Mitsui Chemicals) was used.

[0217] Aerosil R-972 (Nippon Aerosil; average particle size 100 nm) was used for the silica particles. Chromofine Black Al103 (Dainichi Seika Kogyo) was used as the pigment. Takenate D-120N (Mitsui Chemicals) was used as the curing agent.

[0218] For Example 14, the paint used to form the resin region 123 was prepared by weighing 0.75 g of silica, 13 g of resin, 3.9 g of hardener, and 20 g of thinner, and stirring them for 10 minutes in a planetary rotating device (AR-100, Sinky) to obtain paint T2. Olestar Q-691 (Mitsui Chemicals) was used as the resin. Aerosil R-972 (Nippon Aerosil; average particle size 100 nm) was used as the silica. Takenate D-120N (Mitsui Chemicals) was used as the hardener.

[0219] <Fabrication of heat-shielding film> In Example 14, two samples were prepared with films formed using the following method.

[0220] First, paint T1 was applied to a magnesium alloy metal plate using a spin coater to a thickness of 20 μm, dried overnight at room temperature, and then baked at 130°C for 30 minutes to obtain film M1. Next, paint T2 was applied to the surface of film M1 by pad printing, creating a 10 μm × 8 μm pattern to a thickness of 1.5 μm. Next, after drying overnight at room temperature, it was baked at 130°C for 30 minutes to obtain resin region 123. Next, paint T1 was applied using a spin coater to a thickness of 45 μm, dried overnight at room temperature, and then baked at 130°C for 30 minutes to obtain two samples of Example 14. When a cross-section of one of the two obtained samples was cut and observed, the area ratio of the resin region 123 to the total area of ​​the film cross-section was 0.15 area%.

[0221] [Examples 15-27] In Examples 15-27, samples with paint and film were prepared in the same manner as in Example 14, except that the materials and conditions were as shown in Table 7.

[0222] [Comparative Examples 3-12] In Comparative Examples 3 to 12, samples with paint and film were prepared in the same manner as in Example 14, except that the materials and conditions were as shown in Table 7.

[0223] The change in scratch hardness after the water resistance test of the film, the solar reflectance after the water resistance test, and the temperature reduction effect before and after the light resistance test were performed in the same manner as in Examples 14 to 27 described above.

[0224] [Table 7]

[0225] (Evaluation results) Table 8 shows the results of evaluating the change in scratch hardness after the water resistance test, the solar reflectance after the water resistance test, the temperature reduction effect before and after the light resistance test, and the optical accuracy of the films of Examples 14 to 27 and Comparative Examples 3 to 12 using the method described above. For optical accuracy, films with axial misalignment within the acceptable range were rated A, and those exceeding the acceptable range were rated B.

[0226] [Table 8]

[0227] (Third embodiment) In this embodiment, we describe an article having a film that achieves both aesthetic appeal and heat-shielding properties, even if it is a single layer. Descriptions of parts that are the same as those in the first embodiment may be omitted.

[0228] [Methods for achieving both aesthetic appeal and heat-shielding properties] (Methods for ensuring the aesthetic appeal of the exterior color) For example, to ensure the aesthetic appeal of the external color of articles such as lens barrels, it is common practice to form a film on a substrate that has been adjusted to the desired color using a coloring agent. However, if the film's color tone is dark, a large amount of dark coloring agent must be included in the film. When a film contains a large amount of dark coloring agent, the absorption of visible light increases, leading to a greater temperature rise due to sunlight and a deterioration of heat shielding properties. In this embodiment, an organic pigment is used as the dark coloring agent, and the organic pigment is distributed more on the air interface side than on the substrate side within the film. This makes it possible to obtain a film of the desired color even with a smaller amount of organic pigment than originally intended. In order to distribute the organic pigment more on the air interface side than on the substrate side of the film, only the organic pigment contained in the film is intentionally aggregated. Then, by convection during film formation, only the aggregated organic pigment is segregated to the air interface side within the film, and it has been found that the desired color can be achieved even with a small amount of dark color component. To achieve this, a film is obtained by coating a substrate with a paint containing at least a resin, an organic pigment, an inorganic pigment, and a dispersant, and the dispersant used has the effect of aggregating the organic pigment more than the inorganic pigment. For example, by using an alkylol ammonium salt as a dispersant, it was discovered that this allows only the organic pigment to aggregate and segregate it towards the air interface.

[0229] (Methods to ensure heat shielding) For example, in order to ensure the heat shielding properties of an object such as a lens barrel, it is necessary to reflect infrared rays from sunlight. Figure 1 is a schematic cross-sectional view showing the state of reflection and absorption of sunlight in a film according to this embodiment. In Figure 1, 1 is incident light, 2 is reflected light, 3 is transmitted light, 4 is the film, and 5 is the substrate. The wavelength of sunlight is in the range of approximately 0.3 μm to approximately 3 μm, and as shown in Figure 1, when light of these wavelengths becomes transmitted light 3, it is converted into thermal energy, and the substrate 5 generates heat. Therefore, in order to suppress heat generation due to sunlight without an insulating layer, it is necessary to increase the ratio of reflected light 2 to incident light 1 as much as possible to suppress heat generation due to light transmission into the interior.

[0230] The wavelength range of sunlight, from 0.3 μm to 3 μm, is the region of Mie scattering for particles with a diameter of several micrometers. Based on Mie scattering calculations, the reflectivity of sunlight is highest when the particle size is around 1 μm. Therefore, the particle size of sunlight reflecting particles is generally around 1 μm.

[0231] For the reflective particles of sunlight to reflect infrared rays more efficiently, it is desirable that the reflective particles are uniformly dispersed within the film 4. If the reflective particles are not uniformly dispersed, the temperature rise suppression effect will be reduced.

[0232] Examples of particles that reflect sunlight include white titania particles and colored inorganic pigments. By uniformly dispersing inorganic pigments in a film, sufficient infrared reflection can be achieved.

[0233] (Methods for achieving both aesthetic appeal and heat insulation) In this embodiment, to ensure both the aesthetic appearance and heat shielding properties of the lens barrel, the segregation of organic pigments toward the air interface is utilized to adjust the desired color only on the surface of the film, thereby ensuring aesthetic appeal. Furthermore, heat shielding properties are ensured by efficiently reflecting infrared rays through the uniform dispersion of titania particles or infrared-reflective colored inorganic pigments within the rest of the film (from the center toward the substrate interface).

[0234] Figure 8 shows a schematic cross-sectional view of the film according to this embodiment. The cross-section of the film shown in Figure 8 is a schematic diagram of a section cut out from the air interface 221 in the film thickness direction (direction A) to the substrate 205 in an article on which the film is formed, in a direction parallel to the normal direction of the film surface, with a width W. In Figure 8, 221 is the air interface of the film 204, 222 is the substrate interface of the film 204, 223 is the resin, 224 is the organic pigment, and 225 is the inorganic pigment. In this embodiment, since the example shows that the surface of the film 204 is air, 221 is referred to as the air interface. However, even if another film is formed on top of the film 204, the interface of the film 204 with the other film will be referred to as the air interface in this embodiment. Furthermore, if the resin region described in the second embodiment is formed within the film, the cross-section is cut out from the air interface 21 in the film thickness direction (direction A) to the resin region. As shown in Figure 8, the cut-out cross-section is divided into 10 parts with respect to the film thickness direction A (the air interface side is designated as 1 and the substrate side as 10). In that cross-section, it was found that if the organic pigment content is set to 100% area, then 70% to 95% area is distributed in the film thickness direction within ranges 1 to 3, which allows for both aesthetic appeal and heat shielding properties to be achieved. In other words, it was found that both can be achieved if 70% to 95% area of ​​the organic pigment content is contained in a 30% region in the film thickness direction of the cross-section cut from the air interface side toward the substrate interface side of the film. In this embodiment, the content of the organic pigment 224 is obtained by measurement as follows. First, five cross-sections of the film are cut. The cross-sections of the film are cut with a width W (e.g., 1 μm) in a direction parallel to the normal direction of the film surface. The normal direction of the film surface is the normal direction of the plane connecting the convex parts if there are irregularities on the film surface. These five cross-sections are magnified 100,000 times using transmission electron microscopy (TEM). Next, the particles at the five locations are analyzed using Energy Dispersive X-ray Spectroscopy (EDS) to calculate the content per unit area. Finally, the content of the organic pigment 224 contained in the film 204 according to the present invention is calculated from the average value of five locations. In this embodiment, the content calculated by this method is expressed as area %.

[0235] In other words, for example, the film 204 contains organic pigment in an area of ​​0.1% to 2.0% when the cut cross-section is considered as 100% area. In this case, if 70% to 95% of the organic pigment content is contained within the range of 1 to 3 from the air interface side of the film 204, both aesthetic appeal and heat shielding properties can be achieved. The range of 1 to 3 from the air interface side of the film 204 is, in other words, the 30% region from the air interface side toward the substrate side when the length of the film 204 from the air interface side toward the substrate side is considered as 100%. However, if it is less than 70% area, more organic pigment 224 must be included to ensure the aesthetic appeal of the appearance color, resulting in a deterioration of heat shielding properties. Also, if it exceeds 95%, an interface is formed in the range of 1 to 3 from the air interface side of the film (in other words, the range up to 30% of the film thickness from the air interface side), and infrared rays penetrate into the film due to unwanted interfacial reflection, hindering the temperature rise suppression effect. The range from 1 to 3 from the air interface side of the film is defined as the range from the point located at 30% of the length from the film interface on the air interface side, when the length from the air interface side to the substrate side of the cut-out film cross-section is taken as 100%, to a line parallel to the substrate that passes through this point. In this embodiment, the length from the air interface side to the substrate side is defined as the length from the air interface side interface of the film to the substrate, or the length from the air interface side interface to the resin region. If there are irregularities on the air interface side of the cut-out film cross-section, the line parallel to the substrate that passes through the most recessed part (the part where the length from the air interface side of the film cross-section to the substrate (or resin region) is shortest) is defined as the air interface side of the film.

[0236] [Paint according to this embodiment] The following describes the material composition of the paint according to this embodiment and the method for manufacturing the paint of the present invention.

[0237] 《Material Composition》 The coating according to this embodiment comprises at least a resin, an organic pigment, an inorganic pigment, and a dispersant.

[0238] (Resin components) Next, the resin contained in the paint of this embodiment will be described.

[0239] Examples of the resin of the present embodiment include epoxy resin, urethane resin, acrylic resin, urethane acrylate resin, phenol resin, and alkyd resin. These resins may be used singly or in combination of a plurality of types.

[0240] In addition, when the total amount of the paint is 100% by weight, the content of the resin contained in the paint according to the present embodiment is preferably 5% by weight or more and 80% by weight or less, and more preferably 15% by weight or more and 50% by weight or less. When the content of the resin contained in the paint according to the present embodiment is less than 5% by weight, the adhesion to the substrate may deteriorate or the toughness of the film may decrease. Further, when the content of the resin contained in the paint according to the present embodiment exceeds 50% by weight, the solar reflectance of sunlight may deteriorate. The paint mainly consists of a solvent component that volatilizes and disappears when formed into a coating film, a resin component that remains in the film, and a pigment. Therefore, the content of the resin component and the pigment in the paint is determined by drying and firing the paint under various conditions to obtain the solid content concentration.

[0241] (Organic pigment) As the organic pigment contained in the paint according to the present embodiment, azo-based organic pigments and perylene-based organic pigments are used.

[0242] As the azo-based organic particles, any particles can be used as long as they are compounds having an azo group. Examples of the color of the azo-based organic particles of the present embodiment include black, yellow, red, orange, etc., but black is more preferable because the color change (a*, b*) when fading due to sunlight occurs is small. Further, it is preferable that the reflectance of sunlight is high, and it is preferable to select a material having a solar reflectance of more than 10% for the azo-based organic particles alone. Examples of the azo-based organic particles include nickel azo pigments, insoluble azo pigments, soluble azo pigments, high molecular weight azo pigments, azomethine azo pigment-based pigments, and the like. These azo-based organic particles may be used singly or in combination of a plurality of types.

[0243] The average particle size of the organic pigment in this embodiment is preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.1 μm or more and 2.0 μm or less. When the average particle size of the organic pigment in this embodiment is less than 0.1 μm, the surface area of the particles increases, so the light resistance deteriorates and discoloration may occur. Further, when the average particle size of the organic pigment in this embodiment exceeds 5.0 μm, the unevenness of the film becomes large and the film thickness accuracy deteriorates. Therefore, when this embodiment is used for a lens barrel, the accuracy such as focusing may decrease.

[0244] The average particle size in this embodiment is the average of the particle sizes of a plurality of resin particles. The average particle size of the resin particles is obtained by dispersing them in water and analyzing them by the laser scattering method. In this embodiment, the average particle size of the resin particles is the volume average particle size.

[0245] The average particle diameter of the organic pigment in this embodiment is more preferably larger than the average particle diameter of the inorganic pigment described later in order to easily cause segregation to the air interface side due to aggregation of the organic pigment.

[0246] Moreover, particles of any shape can be used for the organic pigment. Examples thereof include spherical, cubic, elliptical, plate-like, layered, chain-like, hollow, star-shaped, needle-shaped, and irregular shapes. Among them, shapes such as plate-like, layered, and chain-like that easily cause segregation to the air interface side due to aggregation of the organic pigment are more preferable.

[0247] These organic pigments may be used singly or in combination of a plurality of types, but it is preferable to use them within a range that does not impair the design property and the heat shielding property.

[0248] Moreover, the content of the organic pigment contained in the paint according to this embodiment is preferably 0.01% by weight or more and 1.0% by weight or less, more preferably 0.015% by weight or more and 0.5% by weight or less when the total paint is 100% by weight. When the content of the organic pigment is less than 0.01% by weight, the lightness of the film becomes too high and the design property deteriorates. Also, the antifouling property may deteriorate. Further, when the content of the organic pigment is 1.0% by weight or more, the lightness of the film becomes too low and the heat shielding property deteriorates.

[0249] (Inorganic pigments) Any inorganic pigment with excellent heat-shielding properties can be used as the inorganic pigment in this embodiment, but it is preferable to include titania particles whose surface is coated with silica. It is preferable to further include colored inorganic pigment for color adjustment. It may also include particles containing Ti and O whose surface is not coated. The particles containing Ti and O whose surface is not coated may be colored inorganic pigment. In this embodiment, particles containing Ti and O whose surface is not coated may simply be referred to as particles containing Ti and O.

[0250] Titania has a high refractive index, making it easy to adjust the film to the desired refractive index. Furthermore, its light color makes it easy to adjust the coating to the desired hue. Additionally, it can be suitably used because a large number of sufficiently finely atomized particles are readily available and relatively inexpensive.

[0251] In this embodiment, the content of silica-coated titania particles in the film is preferably 10% to 70% by weight relative to the resin composition, and more preferably 20% to 60% by weight. If the content is less than 10% by weight, a sufficient infrared reflection effect may not be obtained, and if it is more than 70% by weight, a film with sufficient quality may not be obtained. By using silica-coated particles, photocatalytic activity can be suppressed, thereby reducing the degradation of the surrounding resin.

[0252] Furthermore, the average particle diameter of the silica-coated titania particles in this embodiment is preferably 0.1 μm or more and 1.5 μm or less, and more preferably 0.1 μm or more and 1.0 μm or less. If it is less than 0.1 μm, the surface area of ​​the particles increases, making the silica-coated titania particles more prone to aggregation, and making it difficult to disperse them appropriately in the film. Also, if it is greater than 1.5 μm, as will be described in detail later, it inhibits the segregation of the organic pigment toward the air interface, and it becomes impossible to achieve sufficient performance to balance design and heat shielding properties. In this embodiment, silica-coated titania particles are defined as those in which at least a part of the surface is covered with silica. Furthermore, the average particle diameter of silica-coated titania particles in this embodiment refers to the volume sphere equivalent diameter of unaggregated particles.

[0253] The titania particles coated with silica on the surface in this embodiment can be manufactured by known methods such as gas-phase or liquid-phase methods, as long as their refractive index and average particle size satisfy the desired conditions. For example, known methods include a method of synthesizing titanium dioxide nanoparticles by introducing metal powder into a flame and burning it in an atmosphere containing at least oxygen, and a sol-gel method in which titanium alkoxide is hydrolyzed and polycondensed in the presence of a catalyst. Furthermore, titania is known to have crystalline structures such as rutile and anatase structures, which exhibit a higher refractive index compared to amorphous structures, but any crystalline form can be suitably used as long as it satisfies the desired particle size.

[0254] The inorganic pigment according to this embodiment may contain a colored inorganic pigment in addition to the titania particles whose surface is coated with silica as described above. The content of the infrared-reflective colored inorganic pigment in this embodiment is preferably 0.01% by weight or more and 2.0% by weight or less, and more preferably 0.02% by weight or more and 1.5% by weight or less. If the content of the infrared-reflective colored inorganic pigment in this embodiment is less than 0.01% by weight, the photocatalytic effect when irradiated with sunlight will be small, which may cause a large change in the appearance color of the film of this embodiment. If the content of the infrared-reflective colored inorganic pigment in this embodiment exceeds 2.0% by weight, the heat shielding performance may deteriorate. Furthermore, it is more preferable that the infrared-reflective colored inorganic pigment in this embodiment is uniformly dispersed in the film.

[0255] Furthermore, the material may also contain uncoated Ti and O particles. Since the Ti and O particles need to cleave the resin's molecular chains through photocatalysis, it is preferable that there is little to no coating of light-resistant silica or similar material. This is because we want the photocatalytic action of the uncoated Ti and O particles to cause the film's brightness to decrease when irradiated with sunlight. The reason for this will be explained below. The azo-based organic particles mentioned above as organic pigments are colored pigments that have an azo group, RN=NR', in their molecules. Azo-based organic particles have the characteristic of having higher infrared reflection performance compared to inorganic pigments, but when irradiated with sunlight, the azo group in azo-based organic particles is cleaved into 2R and N2. Since azo-based organic particles exhibit color due to the N=N group and the surrounding atomic arrangement contained within the azo-based organic particles, when N=N is cleaved, the color disappears and the brightness increases. In other words, the color of the film formed on the surface of an object such as an optical instrument may change significantly. This change is more pronounced the smaller the amount of azo-based organic particles.

[0256] On the other hand, in particles 10 containing Ti and O, the TiO2 portion within the particles is excited by the photocatalytic action of sunlight, becoming excited particles containing Ti and O. These Ti and O particles, excited by sunlight, release electrons (e-) into the resin, and the molecular chains of the resin are broken by the electron energy. As a result, the resin becomes discolored and its brightness decreases.

[0257] Thus, in the film according to the present invention, when irradiated with sunlight, the brightness of the azo organic particles changes to a high degree, while the brightness of the particles containing Ti and O changes to a low degree, so overall, color change is suppressed by a cancellation effect. The particles containing Ti and O include particles containing only Ti and O (e.g., titania particles), and / or particles containing one or more inorganic metals in addition to Ti and O. Examples of particles containing one or more inorganic metals in addition to Ti and O in this embodiment include (Ti, Ni, Sb)Ox and (Ti, Cr, Sb)Ox. Also, examples include (Ti, Fe, Zn)Ox, (Co, Cr, Zn, Al, Ti)Ox, (Co, Cr, Zn, Ti)Ox, (Co, Al, Ni, Ti)Ox, etc. Furthermore, examples of particles containing Ti and O in the present invention include the above-mentioned (Ti, Ni, Sb)Ox, (Ti, Cr, Sb)Ox, and (Ti, Fe, Zn)Ox. Other examples include (Co, Cr, Zn, Al, Ti)Ox, (Co, Cr, Zn, Ti)Ox, and (Co, Al, Ni, Ti)Ox. If particles containing Ti and O are included, their content is preferably 1.6% by weight or less.

[0258] (Silica particles) In this embodiment, silica particles may also be included. The average particle size is preferably 10 nm to 110 nm. When the average particle size is 10 nm to 110 nm, it has the effect of filling in the minute defects in the silica of the titania particles whose surfaces are coated with silica, and has the effect of suppressing discoloration in an oxygen-free atmosphere. If the average particle size of the silica particles in this embodiment is less than 10 nm, the ability to fill in the minute defects in the silica of the titanium oxide particles whose surfaces are coated with silica decreases, so the effect of suppressing discoloration in an oxygen-free atmosphere may deteriorate. Also, if the average particle size of the silica particles contained in the paint of the present invention exceeds 110 nm, the adsorption capacity to titanium oxide decreases, so the effect of reducing discoloration in an oxygen-free atmosphere may deteriorate.

[0259] The silica particles can be of any shape. Examples of silica particle shapes include spherical, amorphous, star-shaped, chain-like, hollow, and porous. These silica particles can be of one type or a combination of multiple types.

[0260] In this embodiment, the particle diameter of the silica particles 128 is the average particle diameter based on the number of particles. The average particle diameter of the silica particles 128 can be measured by dynamic light scattering when the paint is in its pre-coating state. When measuring from the state of the film, first, five samples of 300 nm thickness and 5 μm × 5 μm are cut from the film according to this embodiment and magnified 100,000 times using transmission electron microscopy (TEM). Next, the silica particles 128 are analyzed at the five locations using Energy Dispersive X-ray Spectroscopy (EDS) to determine the particle diameter of each silica particle 128 and calculate its average value. Finally, the average value of the five locations is calculated. This average value of the five locations is taken as the average particle diameter of the silica particles contained in the film according to this embodiment. In this embodiment, for example, as shown in Figure 7(c), if silica particles 128 between 10 nm and 50 nm aggregate to form secondary particles, the coatability can be improved if the longitudinal length of the secondary particles is between 50 nm and 350 nm. In particular, it is preferable to select chain-like silica particles in which spherical silica particles 128 are linked together. Chain-like silica particles in which spherical silica particles 128 are linked together are preferable because when applying a coating for forming a light-shielding film, the space created by the silica particles 128 is large, making it easier for the particles 127 to move.

[0261] The silica particle content is 0.6% by mass or more and 14% by mass or less relative to the non-volatile components in the paint, preferably 1% by mass or more and 10% by mass or less. If the silica particle content is less than 0.6% by mass, the minute defects in the silica of the silica-coated titanium oxide particles cannot be filled, which may worsen discoloration in an oxygen-free atmosphere. Also, if the silica particle content of the present invention exceeds 14% by mass, the haze of the coating film will worsen, which may worsen the reflectivity. The silica particle content relative to the non-volatile components in the paint can be measured after the paint has cured, using the same method as for measuring the silica particle content in the film according to the present invention, as described later.

[0262] (Dispersant) As the dispersant contained in the paint of the present embodiment, any dispersant can be applied as long as it has the effect of aggregating organic pigments more than inorganic pigments. In particular, it is preferably contained an alkylol ammonium salt. Originally, the role of a dispersant is to adsorb on the surface of pigments, keep them separated from each other, maintain a constant distance between the pigments, and prevent the pigments from aggregating. However, the dispersant in the present embodiment preferably aggregates organic pigments and disperses inorganic pigments.

[0263] Moreover, the dispersant of the present invention preferably has at least an acid group. Also, the acid value (mgKOH / g) of the dispersant of the present invention is preferably 30 or more and 100 or less. When the acid value (mgKOH / g) is in the range of 30 or more and 100 or less, organic pigments can be more appropriately deposited on the air interface side. Also, the addition amount of the dispersant with respect to the organic pigment is preferably more for the dispersant. When the amount of the dispersant is less, some of the organic pigments are dispersed and the segregation to the air interface side is reduced.

[0264] <s Also, the content of the dispersant of the present invention is preferably 0.1% by weight or more and 10.0% by weight or less, more preferably 0.15% by weight or more and 7.0% by weight or less. When the content of the dispersant is less than 0.1% by weight, the heat insulation property deteriorates. Also, when the content of the dispersant is 10.0% by weight or more, the refractive index of the film becomes low and the reflection due to the refractive index difference becomes small.

[0265] (Solvent) Next, the solvent contained in the paint will be described.

[0266] As the solvent, any material can be used. Examples of the solvent include water, thinner, ethanol, isopropyl alcohol, n-butyl alcohol, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, and methyl ethyl ketone. Also, methyl isobutyl ketone, propylene glycol monomethyl ether, toluene, xylene, acetone, cellosolves, glycol ethers, and ethers can be mentioned. These solvents may be used alone or in combination of multiple types.

[0267] The preferred viscosity of the paint of the present invention is 10 mPa·s or more and 10,000 mPa·s or less, and more preferably 20 mPa·s or more and 1,000 mPa·s or less. If the viscosity of the paint is less than 10 mPa·s, there may be areas where the thickness of the heat-shielding film after application is thin. Also, if it exceeds 10,000 mPa·s, the applicability of the paint may decrease.

[0268] (Other additives) The coating used in the optical instrument of this embodiment may contain other optional additives. Examples include curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, matting agents, preservatives, UV absorbers, antioxidants, coupling agents, and the like.

[0269] 《Method of manufacturing paint》 The method for manufacturing the paint of this embodiment will be described below.

[0270] The method for manufacturing the coating for forming the film on the upper surface of the optical instrument in this embodiment can be any method that allows the organic particles and inorganic pigments of the present invention to be dispersed in the coating. Examples include bead mills, ball mills, jet mills, three-roller mills, planetary rotating devices, mixers, ultrasonic dispersers, homogenizers, and the like.

[0271] [film] The following describes the material composition of the film in this embodiment.

[0272] The film of this embodiment comprises at least a resin, an organic pigment, and an inorganic pigment.

[0273] 《Material Composition》 (Resin components) The resin content in this embodiment is preferably 20% to 90% of the surface area, and more preferably 30% to 80% of the surface area. If the resin content in this embodiment is less than 20% of the surface area, the adhesion to the substrate may deteriorate. Also, if the resin content in this embodiment exceeds 90% of the surface area, the solar reflectance may deteriorate.

[0274] (Organic pigments) The organic pigment content of the present invention is preferably 0.1 area% to 2.0 area%, and more preferably 0.15 area% to 1.5 area%. If the organic pigment content is less than 0.1 area%, the brightness of the film becomes too high, resulting in poor aesthetic appeal. There is also a risk that the antifouling properties will deteriorate. If the organic pigment content is 2.0 area% or more, the brightness of the film becomes too low, resulting in poor heat shielding properties.

[0275] (Inorganic pigments) The content of titanium particles coated with silica, which are an example of an inorganic pigment used to adjust the brightness in this embodiment, is preferably 10% to 80% of the surface area, and more preferably 20% to 60% of the surface area. If the content of the inorganic pigment used to adjust the brightness in this embodiment is less than 10% of the surface area, the coloring power will be weak, and it may be difficult to achieve a brightness of 50 or higher. Furthermore, if the content of the inorganic pigment used to adjust the brightness in this embodiment exceeds 80% of the surface area, the brittleness of the film may worsen and become brittle.

[0276] Furthermore, the content of the colored inorganic pigment in this embodiment is preferably 0.1 area% to 3.0 area%, and more preferably 0.2 area% to 2.0 area%. If the content of the colored inorganic pigment in this embodiment is less than 0.1 area%, the photocatalytic effect when irradiated with sunlight will be low, which may lead to a large change in the appearance color of the film. If the content of the colored inorganic pigment exceeds 3.0 area%, the heat shielding performance may deteriorate.

[0277] Furthermore, it is more preferable that the colored inorganic pigment is uniformly dispersed within the film.

[0278] (Other additives) The coating used in the optical instrument of this embodiment may contain other optional additives. Examples include curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, matting agents, preservatives, UV absorbers, antioxidants, coupling agents, and the like.

[0279] 《Membrane composition》 The film formed on the upper surface of the optical device in this embodiment is formed at least outside the substrate. It may be in close contact with the substrate, or a primer layer may be provided between the substrate and the film formed on the upper surface of the optical device to improve adhesion.

[0280] (base material) Any material can be used as the base material, but metals and plastics are preferred. Examples of metal materials include aluminum, titanium, stainless steel, magnesium alloys, and lithium-magnesium alloys. Examples of plastics include polycarbonate resin, acrylic resin, ABS resin, and fluororesin.

[0281] Furthermore, while the film thickness of the substrate can be any thickness, it is preferably 0.5 mm to 5 mm, and more preferably 0.5 mm to 2 mm. If the film thickness is less than 0.5 mm, it becomes difficult to maintain the shape of the lens barrel. Also, if the film thickness exceeds 5 mm, the cost of the component increases.

[0282] (Primer) A primer may be used to improve the adhesion between the substrate and the film. When a primer is used, in this specification, the substrate is defined as the portion up to the primer. In other words, the substrate includes the primer.

[0283] Any material can be used as the primer, but examples include epoxy resin, urethane resin, acrylic resin, silicone resin, and fluororesin. The primer may also contain particles of this embodiment or other particles, colorants, dispersants, curing agents, curing catalysts, plasticizers, thixotropic agents, leveling agents, organic colorants, inorganic colorants, preservatives, UV absorbers, antioxidants, coupling agents, and solvent residues.

[0284] Furthermore, the primer film thickness is preferably 2 μm to 30 μm, and more preferably 5 μm to 20 μm. If the film thickness is less than 2 μm, the adhesion of the film may decrease, and if it exceeds 30 μm, it may adversely affect the positional accuracy.

[0285] (Film thickness of the film in this embodiment) The film in this embodiment is preferably 10 μm or more and 100 μm or less in thickness. More preferably 20 μm or more and 90 μm or less. If the film thickness is less than 10 μm, the solar reflectance may decrease. If the film thickness exceeds 100 μm, it may adversely affect the positional accuracy of optical instruments, and peeling or cracking of the film may occur under environmental conditions.

[0286] Method for forming the film according to this embodiment The film of this embodiment is 10 μm or more and 100 μm or less in thickness. Any coating method and effect method can be used as long as the coating of this embodiment can be applied uniformly.

[0287] Examples of methods for applying the heat-shielding film for optical equipment in this embodiment include brush coating, spray coating, dip coating, and transfer. The heat-shielding film may be a single-layer coating or a multi-layer coating, and may also be textured to enhance its aesthetic appeal.

[0288] Furthermore, the curing method for the film for articles or optical instruments in this embodiment may be left at room temperature, or curing may be accelerated by applying heat or ultraviolet light. Examples of methods for curing by applying heat include heating furnaces, heaters, and infrared heating. The curing temperature is preferably from room temperature to 400°C, and more preferably from room temperature to 200°C.

[0289] 《Membrane properties》 (Solar reflectance) The film of this embodiment preferably has a solar reflectance of 60% or more. If the solar reflectance falls below 60%, the temperature reduction effect decreases.

[0290] (brightness) The film of this embodiment preferably has a brightness L* of 60 or more and 90 or less, and more preferably 71 or more and 80 or less. If the brightness is less than 60, the temperature rise suppression effect deteriorates. If the brightness is 90 or more, the color is white, which may worsen the stain resistance.

[0291] [Examples 28-37] A preferred embodiment of this design is described below.

[0292] The preparation of the coatings, the fabrication of the films, and the characterization of the films in Examples 28 to 37 were carried out by the following methods.

[0293] <Cross-sectional observation of the membrane> An optical microscope was used to observe the cross-section of the film. Subsequently, the cross-sectional images were processed using image analysis software (Image-Pro Plus, manufactured by MediaCybernetics) to evaluate the content distribution of organic pigments in the film thickness direction. The film thickness direction was divided into 10 sections, and the distribution of organic pigment content in the film thickness direction was evaluated for each section, from area 1 to area 10, starting from the substrate interface side to the air interface side.

[0294] <Evaluation of design aesthetics> For the evaluation of aesthetic appeal, a colorimeter (SE-7700; Nippon Denshoku) was used to measure the lightness L*. Samples for measurement were prepared by forming a coating on SUS foil. First, the film of the present invention was applied to the SUS foil to a thickness of 50 μm, and then cured in a firing furnace. After the coating was formed, the L* value of the film on the air interface side was measured using a colorimeter. Next, after peeling the film from the SUS foil, the L* value of the film on the SUS foil interface side was measured. By comparing the difference in lightness between the air interface side and the substrate (SUS foil) interface side of the coating, the presence or absence of distribution of the organic pigment towards the air interface in the film thickness direction was evaluated.

[0295] If the brightness difference (ΔL*) was 0.2 or greater and the brightness on the air interface side was less than the brightness on the substrate interface side, film A was defined as having a higher distribution of organic pigment on the air interface side. If the brightness difference (ΔL*) was 0.2 or greater and the brightness on the air interface side was greater than the brightness on the substrate interface side, film B was defined as having a lower distribution of organic pigment on the air interface side. On the other hand, if the brightness difference (ΔL*) was less than 0.2, film C was defined as having a uniform distribution of organic pigment in the coating film. A; Brightness difference of 0.2 or more AND Brightness on the air interface side < Brightness on the substrate interface side B; Brightness difference of 0.2 or more AND Brightness on the air interface side > Brightness on the substrate interface side C; brightness difference less than 0.2

[0296] In the present invention, film A has good design appeal because it can be adjusted to the desired color even with less organic pigment used to adjust the brightness compared to films B and C.

[0297] <Evaluation of heat shielding properties> The heat shielding performance was evaluated by solar reflectance. Solar reflectance was measured and calculated using the same apparatus and method as in the first embodiment.

[0298] The sample used for measurement was prepared by forming a coating film on a SUS foil. First, the film of the present invention was applied to the SUS foil to a thickness of 50 μm, and then cured in a firing furnace to form the coating film.

[0299] In terms of solar reflectance, a solar reflectance of 70% or higher indicates a high temperature reduction effect and can be considered a very good film. Furthermore, a solar reflectance of 60% to less than 70% indicates a relatively high temperature reduction effect and can be considered a good film. Below 60% solar reflectance, the temperature reduction effect decreases. A: Solar reflectance of 70% or more B: Solar reflectance is between 60% and less than 70% C: Solar reflectance is less than 60% In this invention, a solar reflectance evaluation of A or B indicates good heat shielding performance.

[0300] <Durability evaluation> The durability of the coating film was evaluated using the following method. For the measurement sample, a metal plate measuring 80 mm x 160 mm with a thickness of 1 mm was used, on which the film of the present invention was formed. The metal plate was made of stainless steel, aluminum, titanium, or magnesium alloy. First, the film of the present invention was applied to the metal plate to a thickness of 50 μm, and then cured in a firing furnace to form the coating film. Next, the sample was subjected to repeated thermal shock 100 times in the range of -30°C to 80°C, and then the appearance of the coating film was evaluated.

[0301] Films showing almost no visible changes (A) were evaluated as having very high durability, films showing slight changes in appearance (B) were evaluated as having relatively high durability, and films showing cracking or peeling (C) were evaluated as having poor durability. A: A highly durable membrane B: A relatively durable membrane C: Film with poor durability In this invention, if the durability evaluation is A or B, the film is considered to have no durability issues.

[0302] [Example 28] <Preparation of paint> In Example 28, the paint was prepared by the following method. 100g of resin (equivalent to 45.9 vol%), 130g of inorganic pigment (silica-coated titania) (equivalent to 29.3 vol%), and 1.0g of organic pigment (equivalent to 0.5 vol%) were weighed. Additionally, 4.0g of colored inorganic pigment (equivalent to 0.7 vol%), 5.0g of dispersant (equivalent to 4.1 vol%), and 100g of solvent were weighed. These were stirred in a ball mill for 15 hours to obtain the main component. 1g of hardener (equivalent to 18.4 vol%) was mixed with 10g of the obtained main component to obtain the paint of Example 28.

[0303] The resin used was Olestar Q-691 (Mitsui Chemicals). The organic pigment used was Chromofine Black A1103 (Dainichi Seika Kogyo). The colored inorganic pigment used was #5950 (Asahi Sangyo). The dispersant used was DISPERBY K-180 (Big Chemie Japan), and the inorganic pigment (silica-coated titania) used was D-970 (Sakai Chemical; average particle size 0.26 μm). The curing agent used was Takenate D-120N (Mitsui Chemicals).

[0304] <Membrane fabrication> In Example 28, the film was prepared by the following method. The above-mentioned coating was applied to a magnesium alloy metal plate using a spin coater to a film thickness of 50 μm, dried overnight at room temperature, and then baked at 130°C for 30 minutes to obtain the film of Example 28. In addition, the film of the present invention was applied to SUS foil and a metal plate using a bar coater to a film thickness of 50 μm, dried overnight at room temperature, and then baked at 130°C for 30 minutes to obtain the film of Example 28.

[0305] [Examples 29-37] In Examples 29-37, paints and films were prepared in the same manner as in Example 28, except that the materials and conditions were as shown in Tables 9 and 10. For Example 29, QSC-100 (Denka; average particle size 0.11 μm) was used as the inorganic pigment (silica-coated titania). For Example 30, R-38L (Sakai Chemical; average particle size 0.4 μm) was used as the inorganic pigment (silica-coated titania). For Example 31, the perylene pigment CIPigment Black 32 (BASF; average particle size 0.2 μm) was used as the organic pigment. For Example 33, DISPERBYK (Vic Chemie Japan) was used as the dispersant. For Example 34, ANTI-TERRA-250 (Vic Chemie Japan) was used as the dispersant. For Example 35, DISPERBYK-187 (Vic Chemie Japan) was used as the dispersant.

[0306] [Comparative Examples 13-19] In Comparative Examples 13 to 19, films were prepared in the same manner as in Example 28, except that the materials and conditions were as shown in Table 9. For Comparative Example 13, HT0210 (Toho Titanium; average particle size 2.25 μm) was used as the inorganic pigment (silica-coated titania). For Comparative Example 14, MT-700B (Teika; average particle size 0.08 μm) was used as the inorganic pigment (silica-coated titania). For Comparative Example 17, DISPERBYK-145 (BIC Chemie Japan) was used as the dispersant. For Comparative Example 18, ANTI-TERRA-108 (BIC Chemie Japan) was used as the dispersant. For Comparative Example 19, DISPERBYK-2008 (BIC Chemie Japan) was used as the dispersant. Table 11 shows the materials and amounts added to constitute the films of Comparative Examples 13 to 16. Table 12 shows the evaluation results using the films of Comparative Examples 17 to 19.

[0307] [Table 9]

[0308] [Table 10]

[0309] [Table 11]

[0310] [Table 12]

[0311] (Evaluation results) Table 5 shows the results of evaluating the aesthetic properties, heat shielding properties, and durability of the films of Examples 28 to 37 and Comparative Examples 13 to 19 using the method described above.

[0312] If a C rating was given, it was determined that the film was undesirable for application to the surface of optical equipment.

[0313] [Table 13] [Industrial applicability]

[0314] The film formed on the upper surface of the optical equipment of the present invention can be used on the lens barrels of optical equipment such as cameras, video cameras, and broadcasting equipment, as well as on camera bodies, video cameras, surveillance cameras, weather cameras, and other devices that may be used outdoors. [Explanation of symbols]

[0315] 1 Incident light 2 Reflected light 3 Transmitted light 4. Infrared reflective film 5 Base material

Claims

1. An article having a base material and a film provided on the base material, The aforementioned film comprises a resin, azo organic particles, and particles containing Ti, a metal other than Ti, and O. An article characterized in that, when the film is irradiated with sunlight, the brightness of the azo-based organic particles increases, and the particles containing Ti, metals other than Ti, and O change the brightness of the resin to a lower level through photocatalytic action.

2. The article according to claim 1, wherein, in the cross-section of the film, when the area occupied by the azo organic particles is set to 100, the area occupied by particles containing Ti, metals other than Ti, and O is 25 to 1000.

3. The article according to claim 1 or 2, wherein the brightness of the film after the photocatalytic action has occurred is 50 or higher.

4. The article according to any one of claims 1 to 3, wherein the particles comprising Ti, a metal other than Ti, and O include one selected from the group consisting of Sb, Cr, Fe, and Zn as the metal other than Ti.

5. The article according to any one of claims 1 to 4, wherein, when the cross-sectional area of ​​the film is 100, the area occupied by the azo organic particles is 0.1 or more and 0.4 or less, and the area occupied by the particles containing Ti, a metal other than Ti, and O is 0.1 or more and 1.0 or less.

6. The article according to any one of claims 1 to 5, wherein when the cross-sectional area of ​​the film is 100 area%, the area occupied by the resin is 5 area% or more and 80 area% or less.

7. The article according to any one of claims 1 to 6, wherein the azo organic particles are azomethine black.

8. The article according to any one of claims 1 to 7, wherein the film further comprises titanium oxide particles whose surface is coated with silica.

9. The article according to any one of claims 1 to 8, wherein the film further comprises silica particles.

10. The article according to any one of claims 1 to 9, wherein the brightness of the film after the photocatalytic action has occurred is 71 or more and 80 or less.

11. The aforementioned particles containing Ti, a metal other than Ti, and O are (Ti, Sb, Cr)O ２ and (Ti, Fe, Zn)O ２ The article according to any one of claims 1 to 10, which is one selected from thereto or a mixture thereof.

12. The article according to any one of claims 1 to 11, wherein the average particle diameter of the particles containing Ti, a metal other than Ti, and O is 10 nm or more and 50 μm or less.

13. The article according to any one of claims 1 to 12, wherein the thickness of the film is 10 μm or more and 70 μm or less.

14. The article according to any one of claims 1 to 13, wherein the particles containing Ti, a metal other than Ti, and O are not coated with silica on their surface.

15. An optical device comprising an optical element and / or an image sensor, and a housing that houses the optical element and / or image sensor inside, A membrane is provided on the outside of the aforementioned housing, The aforementioned film comprises a resin, azo organic particles, and particles containing Ti, a metal other than Ti, and O. An optical device characterized in that when the film is irradiated with sunlight, the brightness of the azo-based organic particles increases, and the particles containing Ti, metals other than Ti, and O change the brightness of the resin to a lower level through photocatalytic action.

16. The optical instrument according to claim 15, wherein, in the cross-section of the film, when the area occupied by the azo organic particles is set to 100, the area occupied by particles containing Ti, metals other than Ti, and O is 25 to 1000.

17. The optical instrument according to claim 15 or 16, wherein the brightness of the film after the photocatalytic action has occurred is 50 or higher.

18. The optical instrument according to any one of claims 15 to 17, wherein the particles containing Ti, a metal other than Ti, and O include one selected from the group consisting of Sb, Cr, Fe, and Zn as the metal other than Ti.

19. The optical instrument according to any one of claims 15 to 18, wherein, when the cross-sectional area of ​​the film is 100, the area occupied by the azo organic particles is 0.1 or more and 0.4 or less, and the area occupied by the particles containing Ti, a metal other than Ti, and O is 0.1 or more and 1.0 or less.

20. The optical instrument according to any one of claims 15 to 19, wherein the azo organic particles are azomethine black.

21. The optical instrument according to any one of claims 15 to 20, wherein the film further comprises titanium oxide particles whose surface is coated with silica.

22. The optical instrument according to any one of claims 15 to 21, wherein the film further comprises silica particles.

23. The optical instrument according to any one of claims 15 to 22, wherein the brightness of the film after the photocatalytic action has occurred is 71 or more and 80 or less.

24. The aforementioned particles containing Ti, a metal other than Ti, and O are (Ti, Sb, Cr)O ２ , and (Ti, Fe, Zn)O ２ The optical instrument according to any one of claims 15 to 23, wherein one selected type or a mixture thereof.

25. The optical instrument according to any one of claims 15 to 24, wherein the average particle diameter of the particles containing Ti, a metal other than Ti, and O is 10 nm or more and 50 μm or less.

26. The optical instrument according to any one of claims 15 to 25, wherein the thickness of the aforementioned film is 10 μm or more and 70 μm or less.

27. A paint comprising a curable resin, azo organic particles, and particles containing Ti, metals other than Ti, and O, A paint characterized in that, when the cured paint is irradiated with sunlight, the brightness of the azo-based organic particles increases, and the particles containing Ti, metals other than Ti, and O cause the curable resin to change in brightness to a lower level through photocatalytic action.

28. The paint according to claim 27, wherein when the weight of the azo organic particles contained in the paint is set to 100, the weight of the particles containing Ti, metals other than Ti, and O contained in the paint is 10 or more and 1600 or less.

29. When the weight of the non-volatile component in the aforementioned paint is set to 100, The weight of the azo organic particles contained in the paint is 0.1 or more and 1.0 or less. The paint according to claim 27 or 28, wherein the weight of particles containing Ti, a metal other than Ti, and O contained in the paint is 0.1 or more and 1.6 or less.

30. The paint according to any one of claims 27 to 29, wherein the particles containing Ti, a metal other than Ti, and O include one selected from the group consisting of Sb, Cr, Fe, and Zn as the metal other than Ti.

31. The aforementioned particles containing Ti, a metal other than Ti, and O are (Ti, Sb, Cr)O ２ , and (Ti, Fe, Zn)O ２ The paint according to any one of claims 27 to 30, which is one selected type or a mixture thereof.

32. The paint according to any one of claims 27 to 31, wherein the azo organic particles are azomethine black.

33. The paint according to any one of claims 27 to 32, further comprising titanium oxide particles whose surface is coated with silica.

34. The paint according to any one of claims 27 to 33, further comprising silica particles.

35. The paint according to any one of claims 27 to 34, wherein the average particle size of the particles containing Ti, a metal other than Ti, and O is 10 nm or more and 50 μm or less.

36. A method for manufacturing an article having a film on a substrate, A step of applying the paint according to any one of claims 27 to 35 onto the substrate, The process of curing the aforementioned paint, A method for manufacturing an article, characterized by having the following:

37. The method for manufacturing an article according to claim 36, wherein the paint is cured at a temperature of room temperature or higher and 400°C or lower in the process of curing the paint.

38. The method for manufacturing an article according to claim 36 or 37, wherein the thickness of the film is 10 μm or more and 70 μm or less.

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