Light-absorbing material based on silicon oxynitride, method for producing same, and composition containing same

Abstract

The purpose of the present invention is to provide a novel light-absorbing material based on silicon oxynitride, a method for producing the light-absorbing material, and a composition containing the light-absorbing material. Typically, the purpose of the present invention is to provide a light-absorbing material based on silicon oxynitride which has light-absorbing ability in a wavelength range up to 600 nm and has a light absorption peak at around 400 nm, a method for producing said light-absorbing material, and a composition containing said light-absorbing material. This light-absorbing material based on silicon oxynitride is characterized by including a composition based on silicon oxynitride, having light-absorbing ability in a wavelength range up to 600 nm, and having an absorption peak in the wavelength range of 300-500 nm.

Description

Silicon oxynitride-based light-absorbing material, its manufacturing method, and composition containing the same

[0001] The present invention relates to a silicon oxynitride-based light-absorbing material and a method for producing the same, and in particular to a silicon oxynitride-based light-absorbing material that has an absorption peak in a wavelength range around 400 nm, which is included in ultraviolet light and short-wavelength visible light that are harmful to materials and the human body, typically UVA rays (320-400 nm) that cause photoaging, and blue light (380-495 nm) that is said to lead to autonomic nervous system disorders; a method for producing the same; and a composition containing the same.

[0002] In order to reduce the adverse effects of light, such as material degradation and skin tanning, there is a growing need for shielding technology that absorbs light ranging from ultraviolet rays to short wavelengths of visible light, and various materials capable of absorbing light of such wavelengths have been proposed.

[0003] Organic absorbents are used as a method of removing or reducing ultraviolet rays that are harmful to the skin and eyes, but the problem with organic absorbents is that they themselves are affected by ultraviolet rays and deteriorate over time.

[0004] 2. Description of the Related Art Conventionally, as an inorganic light-absorbing material, ultraviolet and infrared absorbing glass has been known, as disclosed in, for example, Patent Document 1.

[0005] In addition, titanium oxide and zinc oxide powders, which have a UV scattering effect, are known as inorganic UV absorbing and blocking materials, and are sometimes mixed with organic materials for use. However, titanium oxide and zinc oxide can undergo photocatalytic reactions, which can cause deterioration of organic materials when exposed to light. Furthermore, titanium oxide and zinc oxide do not have a high ability to absorb and block long-wavelength UV rays or blue light.

[0006] To address these issues, for example, Patent Document 2 proposes a composite powder comprising an inorganic powder containing a first metal element, a metal oxide (excluding alkaline earth metal oxides) or a metal hydroxide (excluding alkaline earth metal hydroxides) containing a second metal element and coating at least a portion of the surface of the inorganic powder, and an organic compound having an ultraviolet absorbing effect.

[0007] On the other hand, as disclosed in Patent Document 3, silicon oxynitride-based materials have attracted attention as materials that combine excellent properties such as heat resistance, abrasion resistance, and corrosion resistance with industrial productivity and safety, since they can be obtained by firing at relatively low temperatures.

[0008] Patent Document 4 discloses a silicon oxynitride composition that has excellent thermal radiation properties (radiative cooling effect), where the radiative cooling effect is in the wavelength range of 8000 to 13000 nm.

[0009] Patent Document 5 discloses silicon oxynitride glass, in which light transmittance in the wavelength range of 2000 to 2500 nm or 400 to 700 nm is discussed.

[0010] JP 2013-209224 A JP 2020-186180 A JP 10-158003 A JP 2023-55169 A International Publication No. 2023 / 136349

[0011] Various materials are discussed in the above patent documents. However, the ultraviolet and infrared absorbing glass disclosed in Patent Document 1 has issues such as insufficient solvent resistance (e.g., moisture resistance and alkali resistance), heat resistance, and heat-blocking performance. Furthermore, Patent Document 2 uses organic compounds, which could lead to deterioration over time due to ultraviolet rays. Patent Document 3 focuses on silicon oxynitride-based materials but does not examine their light absorption capabilities. Patent Document 4 examines thermal radiation (radiative cooling effect) in the 8,000-13,000 nm wavelength range, but does not examine the absorption and blocking functions of longer-wavelength ultraviolet rays or blue light. Patent Document 5 also does not examine the absorption and blocking functions of longer-wavelength ultraviolet rays or blue light. Thus, no inorganic materials, particularly silicon oxynitride-based materials, are known that absorb ultraviolet rays and low-wavelength visible light, typically UVA rays (320-400 nm) that cause photoaging, or blue light (380-495 nm) that is said to lead to autonomic nervous system disorders. In other words, further material development is required.

[0012] Therefore, an object of the present invention is to provide a novel silicon oxynitride-based light-absorbing material and a method for producing the same, which typically has light absorption in the wavelength range of 600 nm or less and has its light absorption peak at around 400 nm, a method for producing the same, and a composition containing the same.

[0013] As a result of extensive research, the present inventors discovered that when silicon oxynitride is produced by mixing the raw materials, metal silicon and silica, by carrying out the mixing treatment in a dry manner, a silicon oxynitride-based light-absorbing material can be obtained that has hitherto unknown light absorption ability, more specifically, light absorption ability in the wavelength range of 600 nm or less, with its light absorption peak at around 400 nm, and this discovery led to the idea of ​​the present invention.

[0014] The present invention provides the following aspects.

[0015] [1] A silicon oxynitride-based absorbing material, comprising a silicon oxynitride-based composition, having light absorption ability in a wavelength range of 600 nm or less and having an absorption peak in a wavelength range of 300 to 500 nm.

[0016] [2] The silicon oxynitride-based absorbing material according to [1], characterized in that the silicon oxynitride-based absorbing material contains 0.1 mass % to 15.0 mass % metallic silicon as measured by wide-angle X-ray diffraction, i.e., XRD.

[0017] [3] The silicon oxynitride-based light-absorbing material according to [1] or [2], characterized in that the aluminum content is less than 2.0 mass %.

[0018] [4] A method for producing a silicon oxynitride-based light-absorbing material according to any one of [1] to [3], characterized in that metal silicon powder and silica powder are dry-mixed and subjected to a firing reaction at 1400°C to 1600°C in a nitrogen atmosphere at atmospheric pressure to 15 atmospheres.

[0019] [5] A composition comprising the silicon oxynitride-based light-absorbing material according to any one of [1] to [3].

[0020] According to the present disclosure, a novel silicon oxynitride-based light-absorbing material that was previously unknown is provided. A composition containing the silicon oxynitride-based light-absorbing material can also be provided. The silicon oxynitride-based light-absorbing material has light absorption ability in the wavelength range of 600 nm or less and has an absorption peak in the wavelength range of 300 to 500 nm. Therefore, it can absorb ultraviolet light and low-wavelength visible light, typically UVA rays (320-400 nm) and blue light (380-495 nm). This leads to the suppression of photoaging and autonomic nervous system disorders. The absorbing material contains a silicon oxynitride composition as a base, and can have high thermal stability and a high degree of freedom in material form, allowing it to be provided in various forms such as powder, slurry, film, sheet, and grease. A composition containing the silicon oxynitride-based light-absorbing material can also be provided. The composition contains a silicon oxynitride-based light-absorbing material and can absorb ultraviolet light and low-wavelength visible light, typically UVA light (320-400 nm) and blue light (380-495 nm), which can help prevent photoaging and autonomic nervous system disorders.

[0021] Fig. 1 is an example of a chart of K.M. values ​​for explaining light absorption capacity, and Fig. 2 is a diagram for explaining absorption peaks.

[0022] Hereinafter, one embodiment of the present invention will be described in detail, but the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. Furthermore, when multiple upper and lower limit values ​​are specified for a specific parameter, any upper and lower limit values ​​can be combined to form a suitable numerical range.

[0023] A silicon oxynitride-based light-absorbing material, which is one embodiment of the present invention, has light absorption ability in the wavelength range of 600 nm or less, and has an absorption peak in the wavelength range of 300 to 500 nm.

[0024] The presence or absence of light absorption ability and the presence of an absorption peak can be determined by measuring the reflectance spectrum of a silicon oxynitride-based light-absorbing powder in the ultraviolet to near-infrared region using a diffuse reflectance method and then examining a chart of K.M. values ​​obtained by the Kubelka-Munk transformation (also called the K.M. transformation). Figure 1 shows an example of a K.M. value chart, with the vertical axis representing the K.M. value and the horizontal axis representing the wavelength.

[0025] Having light absorption capacity in the wavelength range of 600 nm or less corresponds to being able to observe or calculate a K.M. value in the wavelength range of 600 nm or less. The lower limit of the wavelength here is not particularly limited and may typically be 100 nm, 200 nm, 300 nm, 320 nm, or 380 nm. Generally, the K.M. value is proportional to the extinction coefficient, and the larger the K.M. value, the greater the light absorption capacity. The wavelength range of 600 nm or less includes UVA rays (320-400 nm) that cause photoaging and blue light (380-495 nm) that is said to lead to autonomic nervous system disorders, and the higher the light absorption capacity or K.M. value, the more these harmful rays can be blocked, which is preferable. From this perspective, the higher the light absorption capacity or K.M. value at 600 nm or less, the more preferable, and the K.M. value at the wavelength to be blocked, for example, 600 nm, is. The value is preferably 0.4 or more, more preferably 0.5 or more, and even more preferably 0.6 or more.

[0026] The presence of an absorption peak in the wavelength range of 300 to 500 nm will be explained with reference to FIG. 2. FIG. 2 is an enlarged view of the range including 300 to 500 nm of the K.M. value chart of FIG. 1. In the K.M. value chart shown in FIG. 2, an absorption peak is defined to be present when the straight line connecting the K.M. values ​​at 300 nm and 500 nm (the dashed line in FIG. 2) and the chart line for the K.M. values ​​in that wavelength range (300 to 500 nm) are above said straight line (high K.M. value), or when the integral of the difference between the K.M. value (A) on the chart line and the K.M. value (B) on the straight line between 300 and 500 nm is greater than 0. Here, the integral value is the sum of all the K.M. values ​​measured at wavelengths of 1 nm each. The presence of an absorption peak in the wavelength range of 300 to 500 nm means that the K.M. value is high in the wavelength range of 300 to 500 nm, and the absorption coefficient of light in that wavelength range is high. The wavelength range of 300 to 500 nm includes UVA rays (320-400 nm), which cause photoaging, and blue light (380-495 nm), which is said to lead to autonomic nervous system disorders. The higher the K.M. value or absorption coefficient at that wavelength, the more these harmful rays can be blocked, which is preferable.

[0027] (K.M. Value Obtained by Kubelka-Munk Transformation (K.M. Transformation)) For a silicon oxynitride-based light-absorbing material, the K.M. value of the sample can be calculated by performing Kubelka-Munk Transformation (K.M. Transformation) on the spectrum obtained by measuring the diffuse reflectance of a powder sample of the material.

[0028] A silicon oxynitride-based light-absorbing material, which is one embodiment of the present invention, includes a silicon oxynitride-based composition represented by the composition formula SixOyNz (where x, y, and z are each independently positive real numbers other than 0).

[0029] (Silicon oxynitride composition) A silicon oxynitride composition contains silicon (Si), oxygen (O), and nitrogen (N) as constituent elements. The composition ratio (or molar ratio) of each constituent element is represented by x, y, and z. That is, the composition ratio of silicon (Si) is x, the composition ratio of oxygen (O) is y, and the composition ratio of nitrogen (N) is z. Here, x, y, and z are each independent positive real numbers other than 0.

[0030] The silicon oxynitride-based light-absorbing material is primarily composed of a silicon oxynitride-based composition, and typically contains 50% by mass or more of the silicon oxynitride-based composition relative to 100% by mass of the solid content of the silicon oxynitride-based light-absorbing material. The higher the content, the more easily the properties derived from the silicon oxynitride-based composition are obtained, which is preferable. From this perspective, the content may be preferably 65% ​​by mass or more, and more preferably 85% by mass or more. The upper limit of the content is not particularly limited, and may be 100% by mass, 99%, 98%, 97%, 96%, or 95% by mass.

[0031] The silicon oxynitride-based light-absorbing material may contain any component other than the silicon oxynitride-based composition, typically SiO, SiO ２ and / or Si ３ N ４ and the like. Note that, as the content of these optional components increases, the content of the silicon oxynitride-based composition decreases relatively, making it difficult to obtain the properties inherent in the silicon oxynitride-based composition. Therefore, the content of the optional components may be less than 50 mass%, preferably less than 35 mass%, and more preferably less than 15 mass%, based on 100 mass% of the solid content of the silicon oxynitride-based light-absorbing material. The lower limit of the content of the optional components is not particularly limited, and may be 0 mass%, 1 mass%, 2 mass%, 3 mass%, 4 mass%, or 5 mass%.

[0032] The composition ratio (or molar ratio) of each element constituting the silicon oxynitride composition is measured by inductively coupled plasma atomic emission spectrometry. However, the oxygen (O) content is measured by an oxygen quantification method using an inert gas fusion-infrared absorption method in accordance with JIS R1603:2007. The nitrogen (N) content is measured by an nitrogen quantification method using an inert gas fusion-thermal conduction method in accordance with JIS R1603:2007. The structure of the silicon oxynitride composition can also be estimated by observing it using wide-angle X-ray diffraction (sometimes referred to as XRD).

[0033] (Metallic Silicon Element) In a silicon oxynitride-based light-absorbing material that is one embodiment of the present invention, the silicon oxynitride-based composition may contain 0.1 mass % to 15.0 mass % metallic silicon as measured by wide-angle X-ray diffraction (XRD).

[0034] The metallic silicon contained in the silicon oxynitride-based light-absorbing material in this embodiment will be described.

[0035] As described above, the silicon oxynitride-based light-absorbing material is mainly composed of a silicon oxynitride-based composition. The silicon oxynitride-based composition is a composition containing silicon (Si), oxygen (O), and nitrogen (N) as essential constituent elements, and silicon oxynitride (Si ２ N ２ Therefore, when the silicon oxynitride-based composition is subjected to wide-angle X-ray diffraction (XRD), the peak position observed is such that it is a silicon oxynitride (Si ２ N ２ The peak position may overlap with that observed in the case of silicon oxynitride (SiO). Silicon oxynitride compositions or silicon oxynitride compounds are sometimes referred to as SiO. Here, the term "compound" refers to a compound in which each constituent element is chemically bonded, i.e., in a compounded state, and the chemical bonding of each constituent element is not particularly limited in the case of a "composition." Furthermore, a compound in which each constituent element (e.g., metal silicon) is in a simple state is not in a compounded state, and is therefore different from a compound. In other words, metal silicon in this embodiment may be included in a silicon oxynitride composition, but is different from a silicon oxynitride compound.

[0036] It is believed that the silicon oxynitride composition containing metallic silicon in addition to the silicon oxynitride compound can exhibit light absorption properties different from those obtained by the silicon oxynitride compound alone. That is, it is believed that the composition can have light absorption in the wavelength range of 600 nm or less, with its light absorption peak around 400 nm. Note that "around 400 nm" is a range that can be selected appropriately depending on the context, and for convenience, it may be in the range of 400±100 nm or 400±50 nm.

[0037] Although not wishing to be bound by a particular theory, it is believed that in silicon oxynitride-based compositions, metallic silicon can exist in a variety of states with different absorption wavelengths, which changes the optical properties of the silicon oxynitride-based composition, particularly the silicon oxynitride-based compound itself, making it possible for the composition to have light absorption in a wavelength range of 600 nm or less and its light absorption peak to be around 400 nm. Note that the above theory is not established, and there are still unknown aspects regarding the relationship between the metallic silicon content and light absorption. Therefore, in one embodiment of the present invention, it is not necessary to specify the metallic silicon content in the silicon oxynitride-based light-absorbing material.

[0038] Here, the metallic silicon in one embodiment of the present invention may be unreacted raw material silicon, silicon obtained during the reaction, or both. The content of metallic silicon is not particularly limited as long as it does not impede the effects of the present invention. The content of metallic silicon may be adjusted as appropriate as long as it does not impede the effects of the present invention. Typically, the content of metallic silicon may be 0.1 mass% or more and 15.0 mass% or less, based on the silicon oxynitride-based light-absorbing material (100 mass%). If the content of metallic silicon is less than 0.1 mass%, the desired effect may not be obtained. Therefore, the lower limit of the metal silicon content may be selected appropriately, and may be 0.1 mass% or more, 0.2 mass% or more, 0.3 mass% or more, 0.4 mass% or more, 0.5 mass% or more, 0.6 mass% or more, 0.7 mass% or more, 1.0 mass% or more, 1.5 mass% or more, 2.0 mass% or more, 2.5 mass% or more, 3.0 mass% or more, 3.5 mass% or more, 4.0 mass% or more, 4.5 mass% or more, 5.0 mass% or more, or 5.50 mass% or more. On the other hand, if the metal silicon content exceeds 15.0 mass%, the effect produced by the metal silicon may saturate. Furthermore, the content of the silicon oxynitride-based compound may decrease relatively, and the effect produced by the silicon oxynitride-based compound may decrease. Therefore, the upper limit of the metallic silicon content may be selected as appropriate, and may be 10.0 mass% or less, 9.0 mass% or less, 7.0 mass% or less, 5.9 mass% or less, 5.8 mass% or less, 5.0 mass% or less, 4.0 mass% or less, 3.5 mass% or less, 3.4 mass% or less, or 3.0 mass% or less.

[0039] The content of metallic silicon is measured by wide-angle X-ray diffraction (XRD).

[0040] (Aluminum) The silicon oxynitride-based light-absorbing material, which is one embodiment of the present invention, may contain a small amount of aluminum due to manufacturing reasons.

[0041] The aluminum content is not particularly limited as long as it does not impede the effects of the present invention. Typically, the aluminum content in the raw material to be fired is preferably less than 2.0 mass % based on the silicon oxynitride-based light-absorbing material after firing (100 mass %). When the aluminum content of the raw material to be fired is 2.0 mass % or more, the silicon oxynitride (Si ２ N ２ This may affect the calcination behavior of the silicon oxynitride (O)-based compound, making it difficult to prepare a silicon oxynitride-based composition of the present invention having an absorption peak in the wavelength range around 400 nm. Therefore, the upper limit of the aluminum content of the raw material to be calcined may be appropriately selected, and may be less than 2.0 mass%, 1.5 mass% or less, 1.4 mass% or less, 1.3 mass% or less, 1.2 mass% or less, 1.1 mass% or less, or 1.0 mass% or less. Here, the aluminum contained in the silicon oxynitride-based light-absorbing material of the present invention may be aluminum metal alone or an aluminum compound. The aluminum content refers to the amount converted to aluminum element. The lower limit of the aluminum content is not particularly limited, and may be 0 mass%, 0.01 mass%, 0.02 mass%, 0.03 mass%, 0.04 mass%, 0.05 mass%, 0.1 mass%, 0.15 mass%, or more than 0.2 mass%. There are no particular restrictions on whether an aluminum-containing component is mixed into the silicon oxynitride compound after firing. For example, there is no problem if alumina is mixed in when the fired product is pulverized in a bead mill made of alumina beads, or if alumina is mixed into the resulting silicon oxynitride compound. There is also no problem if aluminum contained as a trace element in the raw material is used.

[0042] The aluminum content is measured by inductively coupled plasma atomic emission spectroscopy of the raw material before firing or the silicon oxynitride compound after firing. The presence or absence of a sialon structure can also be determined by observing the silicon oxynitride composition by wide-angle X-ray diffraction (XRD).

[0043] (Method for producing a silicon oxynitride-based light-absorbing material) A method for producing a silicon oxynitride-based light-absorbing material, which is one embodiment of the present invention, comprises dry-mixing a silicon metal powder and a silica powder, followed by a firing reaction at 1400°C to 1600°C in a nitrogen atmosphere at atmospheric pressure to 15 atmospheres.

[0044] The above-described manufacturing method is one of the preferred methods for manufacturing the silicon oxynitride-based light-absorbing material of one embodiment of the present invention, but the manufacturing method for the silicon oxynitride-based light-absorbing material of one embodiment of the present invention is not limited to this manufacturing method.

[0045] Metallic silicon powder and silica powder are prepared as raw materials. The raw materials may be prepared so as to obtain the desired silicon oxynitride composition, that is, so as to have a desired composition ratio. As for the charged composition ratio, the molar ratio of metallic silicon powder / silica powder is preferably 1.0 to 4.0, more preferably 1.5 to 3.5, and even more preferably 2.0 to 3.0. By controlling the molar ratio as described above, it is possible to obtain a silicon oxynitride composition containing Si and the intermediates SiO and N. ２ It is believed that a highly efficient oxynitriding reaction proceeds due to this.

[0046] The raw materials, metal silicon powder and silica powder, are dry-mixed. Conventionally, in the production of silicon oxynitride-based compositions, the raw materials have generally been mixed by wet mixing, taking into account mixing efficiency and work efficiency. Prior art documents 3 to 5 relate to silicon oxynitride-based compositions. Patent Document 3 uses an imide decomposition method, in which the raw materials are mixed and reacted in a liquid phase. Patent Document 4 mixes metal silicon powder and silica powder with a polyvinyl alcohol solution and pelletizes them. Patent Document 5 does not mix metal silicon powder and silica powder; instead, silica particles are brought into contact with ammonia gas under heating.

[0047] The means for dry mixing is not particularly limited, and a mortar, a ball mill, etc. can be used.

[0048] The dry-mixed metal silicon powder and silica powder are subjected to a firing reaction at 1400°C to 1600°C in a nitrogen atmosphere at atmospheric pressure to 15 atm. Under these conditions, at least a portion of the raw material metal silicon powder and / or silica powder is nitrided and fired, resulting in a silicon oxynitride-based light-absorbing material. The upper limit of the pressure in the nitrogen atmosphere is preferably 10 atm, more preferably 5 atm, even more preferably 3 atm, even more preferably 1.5 atm, and particularly preferably 1.3 atm or lower. The firing reaction temperature is preferably 1400°C to 1550°C, more preferably 1400°C to 1530°C, and even more preferably 1400°C to 1520°C. The firing time may be adjusted appropriately depending on the desired degree of firing and may be as short as several hours.

[0049] By dry-mixing metal silicon powder and silica powder and carrying out a firing reaction under predetermined pressure, atmosphere, and temperature conditions, a silicon oxynitride-based light-absorbing material is obtained that has light absorption ability in the wavelength range of 600 nm or less and has its light absorption peak around 400 nm.

[0050] While not wishing to be bound by any particular theory, it is believed that the silicon oxynitride-based composition obtained in this embodiment has properties not found in silicon oxynitride-based compositions obtained by conventional manufacturing methods involving wet mixing. For example, in the silicon oxynitride-based composition obtained in this embodiment, metallic silicon can exist in a variety of states with different absorption wavelengths, which is thought to change the optical properties of the silicon oxynitride-based composition, particularly the silicon oxynitride compound itself, making it possible for the composition to have light absorption in a wavelength range of 600 nm or less and its light absorption peak at around 400 nm. Note that the above theory is not established, and there are still unknown aspects regarding the relationship between the metallic silicon content and light absorption. Therefore, in the silicon oxynitride-based light-absorbing material, which is one embodiment of the present invention, it is not necessary to specify the metallic silicon content.

[0051] The silicon oxynitride composition obtained by firing may be subjected to appropriate treatments such as drying, pulverization, heating, cooling, pressurization, and decompression. The desired particle size can be achieved by pulverization. During the pulverization process, wet pulverization may be performed as appropriate, and a drying treatment may be performed after the wet pulverization.

[0052] (Composition Comprising Silicon Oxynitride-Based Light-Absorbing Material) In one embodiment of the present invention, a composition is provided, which comprises the silicon oxynitride-based light-absorbing material of one embodiment of the present invention described above. This composition may also be referred to as a silicon oxynitride-based light-absorbing material-containing composition. This composition may also be a resin composition comprising a resin.

[0053] The form of a composition comprising a silicon oxynitride-based light-absorbing material (silicon oxynitride-based light-absorbing material-containing composition), which is one embodiment of the present invention, is not limited as long as it does not interfere with the effects of the present invention. Typically, the silicon oxynitride-based light-absorbing material-containing composition may be an amorphous solid such as a powder or granules, or may be a solid having a regular shape such as a block, pellet, film, or plate. Furthermore, the form of the silicon oxynitride-based light-absorbing material itself is not limited as well. Typically, the silicon oxynitride-based light-absorbing material may be an amorphous solid such as a powder or granules, or may be a solid having a regular shape such as a block, pellet, film, or plate.

[0054] The silicon oxynitride-based light-absorbing material-containing composition may be a liquid such as a slurry, grease, or paint. Examples of solvents for these liquids include water and organic solvents. Examples of organic solvents that can be used include alcohols such as methanol, ethanol, and isobutyl alcohol; ether alcohols such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; esters such as methyl acetate and ethyl acetate; and ketones such as methyl ethyl ketone and cyclohexanone. Depending on the application, one or more solvents may be used in combination. The liquid may also contain an acid, and examples of the acid that can be used include mineral acids such as hydrochloric acid and sulfuric acid, and organic acids such as acetic acid.

[0055] <Additives> Furthermore, the silicon oxynitride-based light-absorbing material-containing composition may contain the following additives as optional components within the range that does not significantly impair the effects of the present invention. Examples of additives that can be used in the composition include inorganic compounds (aluminum oxide (Al ２ O ３ ), zirconium oxide (ZrO ２ ), hafnium oxide (HfO ２ ), magnesium oxide (MgO), titanium oxide (TiO ２ ), vanadium oxide (VO ２ , V ２ O ５ ), boron oxide (BO ３ The heat-shielding and light-shielding substrate may contain, as appropriate, known additives for heat-shielding and light-shielding substrates, such as oxides (metal oxides and non-metal oxides) such as talc and kaolin; alkali metal salts such as sodium carbonate, potassium carbonate, cesium carbonate, potassium chloride, sodium chloride, potassium bromide, potassium iodide, sodium iodide, potassium sulfate, and sodium sulfate; alkaline earth metal salts such as calcium carbonate, magnesium carbonate, calcium chloride, magnesium chloride, barium sulfate, and magnesium sulfate; and phosphates such as magnesium hydrogen phosphate and magnesium hydrogen phosphate), light stabilizers, antioxidants, antiaging agents, heat stabilizers, colorants (e.g., pigments and dyes), lubricants, fillers, antistatic agents, slip agents, antiblocking agents, fibrous reinforcements, particulate reinforcements, plasticizers, foaming agents, weather resistance agents, crystal nucleating agents, crystallization accelerators, release agents, flame retardants, and flame retardant assistants. These additives may be commercially available products or separately synthesized preparations. Furthermore, commercially available products or prepared products may be used after processing such as granulation (aggregation, pulverization) and the like.

[0056] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples.

[0057] Sample powders of silicon oxynitride-based light-absorbing materials were produced under the following various conditions.

[0058] Example 1: 4.83 g of metallic silicon powder (manufactured by Elkem) and 5.17 g of silica powder (manufactured by Elkem) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1425°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in an agate mortar to obtain a sample powder.

[0059] Example 2: 6.02 g of metallic silicon powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) and 4.29 g of silica powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1500°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in an agate mortar to obtain a sample powder.

[0060] Example 3: 6.00 g of metallic silicon powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) and 4.29 g of silica powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1500°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in an agate mortar to obtain a sample powder.

[0061] Example 4: 43.49 g of metallic silicon powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) and 46.51 g of silica powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1600°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 2.5 L / min) to obtain a fired product. The fired product was then pulverized in a mortar to obtain a sample powder.

[0062] Example 5: 5.62 g of metallic silicon powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) and 6.01 g of silica powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1425°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in a mortar to obtain a sample powder.

[0063] Example 6: 106.31 g of metallic silicon powder (manufactured by Elkem) and 113.69 g of silica powder (manufactured by Elkem) were dry-mixed in a ball mill using alumina balls for 6 hours. The dry-mixed powder was fired in an electric furnace at 1425°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in an agate mortar to obtain a sample powder.

[0064] Comparative Example 1: 2.92 g of metallic silicon powder (manufactured by Kojundo Chemical Laboratory Co., Ltd.), 2.08 g of silica powder (manufactured by Fuji Silysia Chemical Ltd.), and a small amount of ethanol were wet-mixed in a ball mill using alumina balls for 6 hours. The wet-mixed powder was fired in an electric furnace at 1500°C for 3 hours under a nitrogen atmosphere at atmospheric pressure (nitrogen flow rate 1 L / min) to obtain a fired product. The fired product was then pulverized in an agate mortar to obtain a sample powder.

[0065] The sample powder of the silicon oxynitride-based light-absorbing material produced above was subjected to structural measurement by wide-angle X-ray diffraction (XRD), elemental analysis, and diffuse reflectance measurement in the following manner.

[0066] [Structural measurement by wide-angle X-ray diffraction (XRD)] The material powder was placed in a measurement holder and measured under the following conditions. The results are shown in Table 1. Model: Rigaku Corporation wide-angle X-ray diffractometer RINT-TTIII model X-ray source: CuKα radiation, tube voltage-tube current: 50 kV-300 mA Optical system: Diffraction line curved crystal monochromator Scanning range: 5-80° Step width: 0.02° Measurement speed: 2° / min

[0067] [Elemental Analysis] To examine the elements in the sample, quantitative analysis was performed under the following conditions. (1) Elements other than O and N: The sample and acid were placed in a decomposition vessel, heated and decomposed by microwave irradiation, and then the volume was adjusted with ultrapure water to obtain a test solution. Elements detected at 10 μg / g or more were qualitatively analyzed using inductively coupled plasma atomic emission spectroscopy (instrument: Agilent Technologies ICP AES Agilent 5110 VDV model), and elements detected at 100 μg / g or more were quantitatively analyzed. The content of metallic silicon was measured through structural measurement by wide-angle X-ray diffraction (XRD) as described above. (2) O and N elements: Using a LECO TCH600 model, O was measured by inert gas fusion-infrared absorption spectroscopy, and N was measured by inert gas fusion-thermal conductivity spectroscopy.

[0068] [Measurement of diffuse reflectance of ultraviolet, visible, and near-infrared light] The obtained sample powder was filled into a measurement holder, and diffuse reflectance was measured under the following conditions. Kubelka-Munk transformation (K.M. transformation) was performed to obtain K.M. values. The results are shown in Table 2. Model: Spectrophotometer V-770 manufactured by JASCO Corporation, integrating sphere unit ISN-923 model Measurement wavelength: 200 to 2500 nm Bandwidth: UV / VIS 5.0 nm, NIR 20.0 nm Response: 0.96 sec Data acquisition: 1 nm Scanning speed: 1000 nm / min Standard white board: Measurement was performed using a Spectralon reflectance measurement adapter manufactured by Labsphere (specular reflection light was removed)

[0069]

[0070] The silicon oxynitride-based light-absorbing materials of the examples were able to measure K.M. values ​​in a wavelength range of 600 nm or less, confirming that they have light absorption ability in the wavelength range of 600 nm or less. Furthermore, for the silicon oxynitride-based light-absorbing materials of the examples, a straight line was drawn connecting the K.M. values ​​at 300 nm and 500 nm in a K.M. value chart, and the chart line for the K.M. values ​​in that wavelength range (300 to 500 nm) was above the straight line (high K.M. value), or the integral of the difference between the K.M. value (A) on the chart line and the K.M. value (B) on the straight line between 300 and 500 nm was greater than 0, i.e., it was confirmed that an absorption peak was present. From these results, it was confirmed that the silicon oxynitride-based light-absorbing materials according to the embodiments of the present invention can absorb ultraviolet light and low-wavelength visible light, typically UVA light (320-400 nm) and blue light (380-495 nm).

Claims

1. A silicon oxynitride-based light-absorbing material comprising a silicon oxynitride-based composition, having light absorption capability in a wavelength range of 600 nm or less, and having an absorption peak in a wavelength range of 300 to 500 nm.

2. The silicon oxynitride-based light-absorbing material according to claim 1, wherein the silicon oxynitride-based composition contains 0.1% by mass to 15.0% by mass of metallic silicon as measured by wide-angle X-ray diffraction, i.e., XRD.

3. A silicon oxynitride-based light-absorbing material according to claim 1 or 2, characterized in that the aluminum content is less than 2.0 mass %.

4. A method for producing a silicon oxynitride-based light-absorbing material according to claim 1, characterized in that metallic silicon powder and silica powder are dry-mixed and then subjected to a firing reaction at 1400°C to 1600°C in a nitrogen atmosphere at atmospheric pressure to 15 atmospheres.

5. A composition comprising the silicon oxynitride-based light-absorbing material according to claim 1 or 2.

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