Zirconium nitride powder containing an alumina-based composition and a method for manufacturing the same

Abstract

The zirconium nitride powder containing the alumina-based composition is a powder in which the alumina-based composition is partially attached to the surface of a particle mainly composed of zirconium nitride, contains aluminum at a rate of more than 1 mass% and 15 mass% or less when the total amount of the zirconium nitride powder containing the alumina-based composition is set to 100 mass%, and has a specific surface area of 30 m 2 / g to 90 m 2 / g. When the powder forms a black patterned film as a black pigment, the light shielding property in the near-infrared region of a wavelength of 1000 nm is relatively high, the patterning property and the shielding property in the visible light region are excellent, and the moisture resistance is good.

Description

Technical Field

[0001] This invention relates to a zirconium nitride powder containing an alumina-based composition suitable for use as an insulating black pigment, and a method for manufacturing the same. In this specification, "alumina-based composition" refers to a composition in which aluminum oxide (Al₂O₃), aluminum hydroxide (Al(OH)₃), and the like are mixed.

[0002] This application claims priority based on Japanese Patent Application No. 2021-157335, filed on September 28, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] This black pigment is dispersed in a photosensitive resin to prepare a black photosensitive composition. This composition is coated onto a substrate to form a photoresist film, and the photoresist film is then exposed using photolithography to form a patterned film. The resulting patterned film is used in the black matrix of image forming elements such as color filters in liquid crystal displays. Carbon black, conventionally used as a black pigment, is conductive and therefore unsuitable for applications requiring insulation.

[0004] For example, Patent Document 1 (refer to claims 1 and 3, and paragraph

[0007] of the specification) discloses a zirconium nitride powder and a method for manufacturing the same. When this zirconium nitride powder is used as a black pigment to form a black patterned film, a high-resolution patterned film is formed, and the formed patterned film has high light-shielding properties. Regarding this zirconium nitride powder, the specific surface area, measured by the BET method, is 20–90 m² / g. 2 / g, in the X-ray diffraction profile, has a peak of zirconium nitride but not a peak of zirconium dioxide, a peak of low-valent zirconium oxide, and a peak of low-valent zirconium oxynitride, and in the transmission spectrum of the dispersion with a powder concentration of 50 ppm, the light transmittance X at 370 nm is at least 18%, the light transmittance Y at 550 nm is less than 12%, and the ratio of the light transmittance X at 370 nm to the light transmittance Y at 550 nm, X / Y, is more than 2.5.

[0005] The zirconium nitride powder shown in Patent Document 1 is manufactured by mixing zirconium dioxide powder coated with zirconium dioxide or silicon dioxide, metallic magnesium powder, and magnesium nitride powder in a ratio of 2.0 to 6.0 moles of metallic magnesium and 0.3 to 3.0 moles of zirconium dioxide to obtain a mixture. The mixture is then calcined at a temperature of 650 to 900°C in an atmosphere of nitrogen alone, a mixture of nitrogen and hydrogen, or a mixture of nitrogen and ammonia, thereby reducing the zirconium dioxide powder to produce zirconium nitride powder.

[0006] However, if the zirconium nitride powder shown in Patent Document 1 is placed in a high temperature and high humidity environment of 80°C and 85%, the surface of the zirconium nitride particles will be oxidized. Therefore, when using the zirconium nitride powder to form a patterned film, there is a problem that the film has insufficient moisture resistance and reduced light-shielding performance.

[0007] To address this issue, Patent Document 2 (claims 1, 2, and paragraph

[0006] of the specification) discloses a zirconium nitride powder and a method for manufacturing the same, which can improve compatibility with acrylic resins and the like, and can improve moisture resistance along with gas barrier properties.

[0008] Furthermore, Patent Document 3 (claims 1, 2, and paragraphs

[0010] and

[0033] of the specification) discloses a black light-shielding film forming powder and a method for manufacturing the same. The black light-shielding film forming powder is used as a black pigment to form a black light-shielding film with excellent ultraviolet transmittance and high-resolution patterning characteristics. The formed black light-shielding film has high light-shielding performance and high weather resistance.

[0009] The zirconium nitride powder shown in Patent Document 2 is a powder composed of zirconium nitride particles coated with alumina, wherein the volume resistivity is 1×10⁻⁶. 6 The alumina coating is above Ω·cm, the alumina coating is 1.5% to 9% relative to 100% zirconium nitride, and the isoelectric point is above 5.7.

[0010] The method for manufacturing zirconium nitride powder shown in Patent Document 2 includes: a step of pulverizing zirconium nitride particles in water to prepare a zirconium nitride slurry; a step of dissolving an aluminum compound in a solvent to prepare an aluminum compound solution; a step of adding the aluminum compound solution to the zirconium nitride slurry in a mass ratio of zirconium nitride particles to alumina of (100:1.5) to (100:15); a step of adding acid to the zirconium nitride slurry containing the aluminum compound solution to adjust the pH of the zirconium nitride slurry, so that the aluminum compound precipitates on the surface of the zirconium nitride particles and coats the zirconium nitride particles with the aluminum compound; a step of washing and recovering the zirconium nitride particles coated with the aluminum compound; and a step of holding the recovered zirconium nitride particles coated with the aluminum compound at a temperature of 60°C to 200°C for 1 hour to 24 hours in an atmospheric or nitrogen atmosphere and calcining them to obtain zirconium nitride particles coated with alumina.

[0011] On the other hand, the black light-shielding film forming powder shown in Patent Document 3 has a specific surface area of ​​20 to 90 m² as determined by the BET method. 2 / g, a powder composed of black opaque film forming particles with zirconium nitride as the main component and containing magnesium and / or aluminum, wherein, when containing magnesium, the content of magnesium is 0.01 to 1.0% by mass relative to 100% by mass of the black opaque film forming powder, and when containing aluminum, the content of aluminum is 0.01 to 1.0% by mass relative to 100% by mass of the black opaque film forming powder.

[0012] In the method for manufacturing black light-shielding film powder shown in Patent Document 3, zirconium dioxide powder, magnesium metallic powder, magnesium oxide powder or magnesium nitride powder, and aluminum oxide powder or aluminum nitride powder are prepared such that the magnesium metallic powder is 25 to 150% by mass relative to 100% of zirconium dioxide (equivalent to 1.27 to 7.6 moles), and the magnesium oxide is 15 to 500% by mass relative to 100% of zirconium dioxide (equivalent to 0.46 to 15.3 moles). The alumina or aluminum nitride is mixed in proportions of 0.02 to 5.0% by mass (equivalent to 0.00048 to 0.12 moles) relative to 100% zirconium dioxide. The resulting mixed powder is then calcined at a temperature of 650 to 900°C under an atmosphere of elemental nitrogen, a mixed atmosphere of nitrogen and hydrogen, a mixed atmosphere of nitrogen and ammonia, or an atmosphere of nitrogen and an inert gas. This process reduces the mixed powder to produce a powder for forming a black light-shielding film.

[0013] Patent Document 1: Japanese Patent Application Publication No. 2017-222559

[0014] Patent Document 2: Japanese Patent Application Publication No. 2020-158377

[0015] Patent Document 3: Japanese Patent Application Publication No. 2019-112275

[0016] In recent years, the demand for shielding the near-infrared region with a wavelength of around 1000nm has been increasing in optical components such as image sensors in order to suppress noise. The demand for films that not only shield the visible light region but also shield this near-infrared region is constantly increasing.

[0017] However, while the powder composed of zirconium nitride particles coated with alumina shown in Patent Document 2 can improve compatibility with acrylic resins and the like, and improve moisture resistance along with gas barrier properties, it has the problem of not being able to improve the light-shielding properties in the near-infrared region with a wavelength of 1000 nm when used as a black pigment to form a black patterned film. The reason for this is that, with the aim of coating the zirconium nitride particles with alumina and suppressing particle sedimentation when used as a photoresist, the zirconium nitride is pulverized in the early stages of manufacturing, miniaturizing the BET specific surface area of ​​the zirconium nitride powder to over 90 μm. 2To reduce crystallinity, the size of the particles is reduced by increasing the size of the particles per gram (average particle size less than 10 nm).

[0018] Furthermore, the black light-shielding film forming powder shown in Patent Document 3 is mainly composed of zirconium nitride, and when aluminum is present, the proportion of aluminum relative to 100% by mass of the black light-shielding film forming powder is 1.0% by mass or less. Patent Document 3 describes that when the proportion exceeds 1.0% by mass, the light-shielding performance of the black light-shielding film is reduced.

[0019] The inventors discovered that when aluminum is used as a reducing agent for zirconium oxide in the aluminothermic process, even with an increase in aluminum content, the visible light shielding of the film does not decrease, the crystallinity of the zirconium nitride particles does not decrease but remains high, and the zirconium nitride particles do not become coarser, thus preventing a decrease in light transmittance in the ultraviolet region. This led to the completion of the present invention.

[0020] Furthermore, the inventors discovered that when aluminum is used as a reducing agent for zirconium oxide in the aluminothermic process, the firing temperature of the mixed powder needs to be set to be higher than 900°C and lower than 1100°C, which is higher than 650°C to 900°C in Patent Document 3, thus completing the present invention. Summary of the Invention

[0021] The purpose of this invention is to provide a zirconium nitride powder containing an alumina-based composition. When this zirconium nitride powder is used as a black pigment to form a black patterned film, it has relatively high light-shielding properties in the near-infrared region with a wavelength of 1000 nm, excellent patternability and shielding properties in the visible light region, and good moisture resistance.

[0022] The first aspect of the present invention is a zirconium nitride powder containing an alumina-based composition, characterized in that the zirconium nitride powder containing the alumina-based composition is obtained by the alumina-based composition being partially adhered to the surface of particles mainly composed of zirconium nitride; when the total amount of the zirconium nitride powder containing the alumina-based composition is set to 100% by mass, the zirconium nitride powder containing the alumina-based composition contains aluminum in a proportion of more than 1% by mass and less than 15% by mass, and the specific surface area measured by the BET method is 30 m². 2 / g~90m 2 / g. The BET specific surface area is a value determined using nitrogen as the adsorbate.

[0023] The second aspect of the present invention is based on the first aspect and is a zirconium nitride powder containing an alumina-based composition. When measuring the transmission spectrum of a dispersion prepared at a concentration of 50 ppm (mass ppm, hereinafter the same) of the zirconium nitride powder containing the alumina-based composition, the light transmittance X at a wavelength of 370 nm is 20% or more, the light transmittance Y at a wavelength of 1000 nm is 35% or less, and the ratio X / Y of the light transmittance X at 370 nm to the light transmittance Y at 1000 nm is 1.2 or more. For example, propylene glycol monomethyl ether acetate (PGM-Ac) solvent is used as the dispersion medium. In the measurement of light transmittance, the optical path length is set to 1 cm (hereinafter the same).

[0024] The third aspect of the present invention is a method for manufacturing zirconium nitride powder containing an alumina-based composition. After obtaining a mixture by mixing zirconium oxide powder, aluminum-containing powder at 0.05 to 0.8 moles of the zirconium oxide powder, metallic magnesium powder at 2.0 to 6.0 moles of the zirconium oxide powder, and magnesium oxide powder at 0.3 to 5.0 moles of the zirconium oxide powder, the mixture is calcined in a nitrogen atmosphere at a temperature exceeding 900°C and below 1100°C for 60 to 180 minutes, thereby reducing the zirconium oxide powder to produce zirconium nitride powder containing an alumina-based composition as in the first or second aspect.

[0025] The fourth aspect of the present invention is a third-party invention, which is a method for manufacturing zirconium nitride powder containing an alumina-based composition, wherein the aluminum-containing powder is any one or more of metallic aluminum, alumina, aluminate compounds and aluminum hydroxide.

[0026] The fifth aspect of the present invention is a black dispersion, which is formed by dispersing zirconium nitride powder containing an alumina-based composition of the first or second aspect in a solvent or monomer compound.

[0027] The sixth aspect of the present invention is a black photosensitive composition comprising zirconium nitride powder containing an alumina-based composition as a black pigment, as described in the first or second aspect.

[0028] The seventh aspect of the present invention is a black patterned film, which is obtained using the black photosensitive composition of the sixth aspect.

[0029] The eighth aspect of the present invention is a black matrix, which is obtained using the black patterned film of the seventh aspect.

[0030] The ninth aspect of the present invention is a light-shielding material, wherein the light-shielding material is obtained using a black patterned film as described in the seventh aspect.

[0031] The tenth aspect of the present invention is a light-shielding filter, which is obtained using the black patterned film of the seventh aspect.

[0032] The eleventh aspect of the present invention is a black film, the black film comprising a support film and a black patterned film of the seventh aspect located on the support film.

[0033] In the zirconium nitride powder containing an alumina-based composition according to the first aspect of the present invention, the alumina-based composition is partially adhered to the surface of particles mainly composed of zirconium nitride. When the total amount of zirconium nitride powder containing the alumina-based composition is set to 100% by mass, aluminum is contained in a proportion exceeding 1% by mass and less than 15% by mass. Unlike the alumina-coated zirconium nitride powder shown in Patent Document 2, the particle surface is not coated with alumina, but rather exists in a state where the alumina-based composition is partially adhered to the surface of the zirconium nitride particles. Since the surface of such zirconium nitride particles is not completely coated with alumina, the inherent optical properties of zirconium nitride are not impaired. As a result, when forming a black patterned film as a black pigment, by partially adhering the alumina-based composition to the surface of the zirconium nitride particles, it exhibits good gas barrier properties and moisture resistance, even when the powder's BET specific surface area is 30 m². 2 / g~90m 2 With a particle size of / g, the crystallinity of zirconium nitride particles does not decrease but remains high, and the zirconium nitride particles are not coarsened. Therefore, the light transmittance in the ultraviolet region with a wavelength of 370nm is high, and the light-shielding effect in the near-infrared region with a wavelength of 1000nm is high (light transmittance is low).

[0034] Furthermore, the BET specific surface area of ​​the zirconium nitride powder containing the alumina-based composition is 30 m². 2 It has a concentration of over / g, therefore it has the effect of inhibiting sedimentation when used as a corrosion resist, and because it is 90m 2 Below / g, it has a sufficient visible light shielding effect.

[0035] The zirconium nitride powder containing an alumina-based composition according to the second aspect of the present invention further features a light transmittance X of 370 nm or more and a light transmittance Y of 1000 nm or less in the transmission spectrum of a dispersion with a powder concentration of 50 ppm, and has the advantage of further transmitting ultraviolet light due to X / Y being 1.2 or more. As a result, when forming a black patterned film as a black pigment, a patterned film with higher resolution can be formed, and the formed patterned film has higher visible light shielding performance.

[0036] The method shown in Patent Document 2 involves adding an aluminum compound to a zirconium nitride slurry and mixing it to prepare aluminum-coated zirconium nitride particles, followed by calcination to produce powder composed of alumina-coated zirconium nitride particles. In contrast, in the third-party method of the present invention for producing zirconium nitride powder containing an alumina-based composition, aluminum powder, magnesium powder, and magnesium oxide powder are mixed in a predetermined ratio in zirconium oxide, and the aluminothermic reduction reaction is carried out at a temperature exceeding 900°C and below 1100°C to produce zirconium nitride powder containing an alumina-based composition. Therefore, the alumina-based composition is locally attached to the surface of the zirconium nitride particles.

[0037] In the manufacturing method of Patent Document 2, the zirconium nitride particles of the starting material are pulverized with the aim of coating the zirconium nitride particles with alumina. Therefore, pulverization will cause a decrease in the crystallinity of zirconium nitride. In contrast, in the method of the third aspect of the present invention, since the zirconium nitride particles are not pulverized and the aluminum-containing particles help the aluminothermic reduction reaction, the crystallinity of the zirconium nitride powder containing the alumina-based composition can be maintained at a high level without reducing the crystallinity.

[0038] The detailed mechanism of the aluminothermic reduction reaction is not yet clear, but it is speculated that: by using aluminum-containing particles as its reaction material, zirconia particles are expected to undergo the following side reactions in the aluminothermic reduction reaction, which can lead to better optical properties.

[0039] When aluminum-containing particles are defined as aluminum oxide, the reduction reaction of magnesium on the aluminum oxide is represented by the following formula (1).

[0040] Al2O3 + 3Mg → 2Al + 3MgO (1)

[0041] The reduction of zirconium oxide by aluminum (aluminothermic reaction) is represented by the following formula (2).

[0042] 2Al + 3ZrO2 → 2AlO3 + 3Zr (2)

[0043] The nitriding reaction of metallic zirconium is represented by the following formula (3).

[0044] Zr + 1 / 2N2 → ZrN (3)

[0045] The reactions shown in formulas (1) to (3) above proceed sequentially and produce a mixture of zirconium nitride and alumina compounds.

[0046] Aluminum metal, like magnesium metal, undergoes an aluminothermic reaction at high temperatures. However, the reaction is considered to be longer and slower than that of magnesium metal. This slows down the reaction, thus preventing zirconium nitride obtained as a reactant from becoming coarse particles and instead producing a small-diameter particle with excellent uniformity. This is particularly helpful in improving transmittance in the ultraviolet region.

[0047] In the manufacturing method of the fourth aspect of the present invention, the aluminum-containing powder is any one or more of metallic aluminum, aluminum oxide, aluminate compounds and aluminum hydroxide. Therefore, during calcination, the particles of any powder are reduced by metallic magnesium to generate metallic aluminum as shown in formula (1) above, and zirconium nitride particles are obtained by formula (2) and formula (3) above.

[0048] The black dispersion of the fifth aspect of the present invention has the advantage of allowing zirconium nitride powder containing an alumina-based composition of the first or second aspect to transmit ultraviolet light while blocking visible light by dispersing it in a solvent or monomer compound. As a result, this black dispersion is suitable for use as a material for forming black patterned films.

[0049] According to the sixth aspect of the present invention, the black photosensitive composition contains zirconium nitride powder containing an alumina-based composition as a black pigment. Therefore, when a black patterned film is formed using this composition, the ultraviolet transmittance is high, thereby enabling the formation of a high-resolution patterned film even with a reduced amount of photoinitiator.

[0050] The black patterned film of the seventh embodiment of the present invention has high resolution and high shielding performance against visible light and near-infrared light.

[0051] The black matrix of the eighth aspect of the present invention is obtained using the aforementioned black patterned film, and therefore has a fine pattern.

[0052] The light-shielding material of the ninth embodiment, the light-shielding filter of the tenth embodiment, and the black film of the eleventh embodiment of the present invention are obtained by using the above-mentioned black patterned film, and therefore have high shielding performance for visible light and near-infrared light. Attached Figure Description

[0053] Figure 1 The spectrum represents the light transmittance of the dispersion of zirconium nitride powder obtained in Example 1, Comparative Example 1, and Comparative Example 2 after diluting the dispersion to a powder concentration of 50 ppm.

[0054] Figure 2 This is a scanning transmission electron microscope (STEM) image of zirconium nitride particles with an alumina-based composition obtained in Example 3 attached.

[0055] Figure 3 This is a flowchart of manufacturing zirconium nitride powder containing an alumina-based composition according to this embodiment. Detailed Implementation

[0056] Next, the method for carrying out the present invention will be described.

[0057] [Method for manufacturing zirconium nitride powder containing an alumina-based composition]

[0058] The characteristic of the method for manufacturing zirconium nitride powder (hereinafter, sometimes referred to as the final product) containing an alumina-based composition according to this embodiment is that the firing temperature of the mixed particles is set to be above 900°C and below 1100°C.

[0059] [A mixture containing aluminum powder, ZrO2 powder, metallic Mg powder, and MgO powder]

[0060] In the manufacturing method of this embodiment, such as Figure 3 As shown, aluminum powder 11 is mixed with zirconia (ZrO2) powder 12, magnesium (Mg) powder 13 and magnesium oxide (MgO) powder 14 to obtain mixture 20.

[0061] The mixture 20 is obtained by mixing zirconium oxide powder 12, aluminum-containing powder 11 in 0.05 to 0.8 molar amounts of zirconium oxide powder 12, metallic magnesium powder 13 in 2.0 to 6.0 molar amounts of zirconium oxide powder 12, and magnesium oxide powder 14 in 0.3 to 5.0 molar amounts of zirconium oxide powder 12.

[0062] [Aluminum-containing powder]

[0063] The aluminum-containing powder 11 in this embodiment is any one or more of metallic aluminum, alumina, aluminate compounds, and aluminum hydroxide. As shown in formula (1) above, the aluminum-containing powder is used to generate metallic aluminum by reduction with metallic magnesium during sintering. Therefore, if the aluminum-containing powder is metallic aluminum, the amount of metallic magnesium used can be minimized. Examples of aluminate compounds include aluminic acid; alkali metal salts such as lithium, sodium, and potassium salts of aluminic acid; alkaline earth metal salts such as magnesium and calcium salts of aluminic acid; and ammonium salts of aluminic acid. Sodium aluminate and potassium aluminate are preferred.

[0064] When the aluminum-containing powder 11 is metallic aluminum powder, the metallic aluminum powder preferably has an average particle size of 1 μm to 20 μm. Below the lower limit, the reaction tends to proceed rapidly, while above the upper limit, the reaction is difficult to proceed smoothly. When the aluminum-containing powder 11 is a powder other than metallic aluminum powder, these powders are ionic compounds and are prone to thermal decomposition; therefore, the average particle size of the aluminum-containing powder 11 is not limited.

[0065] The amount of aluminum-containing powder 11 added relative to zirconium oxide powder 12 affects the amount of metallic aluminum produced. If the amount of aluminum-containing particles is too small, the aluminothermic reduction reaction of aluminum will not easily occur due to insufficient metallic aluminum. If the amount is too large, a compound of aluminum and zirconium, namely ZrAl3, will be formed, and the optical properties of the final product will be reduced. Aluminum-containing powder 11 is added to zirconium oxide powder 12 and mixed in a ratio of 0.05 to 0.8 moles of zirconium oxide. If the ratio is less than 0.05 moles, the amount of metallic aluminum produced is likely to be insufficient; if the ratio exceeds 0.8 moles, the optical properties of the final product will be reduced. It is particularly preferred to be 0.1 to 0.6 moles. Here, the number of moles of aluminum-containing particles is the molecular weight of each aluminum atom constituting the aluminum-containing particles. For example, the number of moles of aluminum oxide is half of the molecular weight of Al2O3, which is 101.96, i.e., 50.98.

[0066] [Zirconium oxide powder]

[0067] As the zirconium oxide powder 12 in this embodiment, any of the following zirconium dioxide powders can be used: monoclinic zirconium dioxide, cubic zirconium dioxide, yttrium-stabilized zirconium dioxide, etc. From the viewpoint of a higher zirconium nitride powder formation rate, monoclinic zirconium dioxide powder is preferred. Zirconia typically contains about 2% by mass of hafnium as an unavoidable impurity, and a level of 2% by mass does not affect optical properties.

[0068] [Magnesium Metal Powder]

[0069] If the particle size of the magnesium powder 13 is too small, the reaction will proceed rapidly, increasing the operational risk. Therefore, it is preferable to use a sieve to obtain granules with a particle size of 100 μm to 1000 μm, and more preferably granules with a particle size of 200 μm to 500 μm. Not all of the magnesium powder 13 needs to be within the above particle size range; as long as 80% or more by mass, especially 90% or more by mass, is within this range, it is acceptable.

[0070] The amount of magnesium powder 13 added relative to zirconium oxide powder 12 affects the reducing power of zirconium oxide. If the amount of magnesium is too small, insufficient reduction will result in difficulty obtaining the desired zirconium nitride particles; if the amount is too large, the excess magnesium will cause a sharp rise in reaction temperature, potentially leading to particle growth and becoming uneconomical. Regarding magnesium powder 13, depending on its particle size, it is added to zirconium oxide powder 12 in a ratio of 2.0 to 6.0 moles of magnesium to zirconium oxide and mixed. If the ratio is less than 2.0 moles, the reducing power of zirconium oxide is likely to be insufficient; if it exceeds 6.0 moles, the excess magnesium will cause a sharp rise in reaction temperature, potentially leading to particle growth and becoming uneconomical. A ratio of 3.0 to 5.0 moles is preferred.

[0071] [Magnesium oxide powder]

[0072] Magnesium oxide powder 14 is used to prevent the sintering of zirconium nitride, which is formed by the reduction reaction of metallic magnesium with zirconium oxide. The amount used varies depending on the particle size of the magnesium oxide, and is preferably 0.3 to 5.0 times the molar ratio relative to 1 mole of zirconium oxide powder. The amount of magnesium oxide powder 14 should only be sufficient to prevent the sintering of zirconium nitride; if too much is used, the amount of acidic solution required for pickling after the reaction will increase, therefore it is preferable to use it within the above-mentioned range.

[0073] [Firing of the mixture]

[0074] The aluminum-containing powder 11, zirconium oxide powder 12, magnesium metal powder 13, and magnesium oxide powder 14 of this embodiment are placed in a reaction vessel (not shown) and calcined into a mixture 20. The temperature at which the magnesium metal used to reduce zirconium oxide powder 12 to generate zirconium nitride powder, i.e., the calcination temperature, exceeds 900°C and is below 1100°C, preferably 950°C to 1000°C. Below the lower limit of 900°C, the aluminum-containing powder cannot be effectively utilized in the aluminothermic reduction reaction, and the reduction reaction of zirconium oxide will not occur sufficiently. Furthermore, even if the temperature is set above 1100°C, the effect will not increase, resulting in wasted heat energy and sintering of the particles, which is not preferable. For the same reasons as the reduction reaction temperature, the reduction reaction time, i.e., the calcination time, is 60 minutes to 180 minutes, preferably 60 minutes to 120 minutes. The atmosphere during the reduction reaction, i.e., the calcination, is a nitrogen atmosphere to prevent oxidation of the reduction products. To promote the above-mentioned reduction reaction, a mixture of nitrogen and hydrogen or a mixture of nitrogen and ammonia can be used. The above mixture 20 is fired to obtain a fired product 21.

[0075] [Treatment of fired products]

[0076] The calcined product 21 obtained by calcining the above mixture is removed from the reaction vessel and cooled to room temperature. It is then washed with an acid solution 22, such as hydrochloric acid aqueous solution, to remove magnesium oxide formed by the oxidation of metallic magnesium, magnesium oxide (MgO) initially present to prevent sintering of the product, and magnesium nitride (Mg3N2) formed during calcination. This acid washing is preferably performed at a pH of 0.5 or higher, especially pH 1.0 or higher, and at a temperature below 90°C. This is because even zirconium may dissolve if the acidity is too strong or the temperature is too high. After this acid washing, the pH is adjusted to 5-6 with ammonia or the like, and the solid components are separated by filtration or centrifugation. These solid components are then dried and pulverized to obtain the zirconium nitride powder 23 containing the alumina-based composition of this embodiment.

[0077] Furthermore, the zirconium nitride powder 23 containing the alumina-based composition may contain impurities that may be present in the process of using raw materials or stainless steel reaction vessels. Examples of such impurities include magnesium salts such as magnesium chloride and magnesium oxide, ammonium salts such as ammonium chloride, fluorine, chlorine, bromine, metallic aluminum, aluminum nitride, carbon, adsorbed water, iron, nickel, chromium, tungsten, molybdenum, vanadium, niobium, titanium, cobalt, potassium, copper, and hafnium compounds. When the zirconium nitride powder 23 containing the alumina-based composition contains trace amounts (e.g., less than 5% by mass) of these impurities, it will not particularly affect its optical properties, electrical insulation, or changes in properties under constant temperature and humidity conditions.

[0078] [Characteristics of zirconium nitride powder containing alumina-based compositions]

[0079] In the zirconium nitride powder containing an alumina-based composition obtained in this embodiment, the alumina-based composition derived from aluminum-containing particles is locally adhered to the surface of particles mainly composed of zirconium nitride. Furthermore, when the total amount of zirconium nitride powder containing the alumina-based composition is set to 100% by mass, aluminum is present on the surface of the particles in a proportion exceeding 1% by mass and less than 15% by mass. When this proportion is less than 1% by mass, the aluminum content on the surface of the zirconium nitride particles is too low to achieve good moisture resistance, and the effects of increased crystallinity and particle fineness uniformity resulting from the aluminothermic reduction reaction containing aluminum are not observed, leading to lower light transmittance at a wavelength of 370 nm. On the other hand, while a proportion exceeding 15% by mass can improve the moisture resistance of the particles, the light-shielding properties in the near-infrared region at a wavelength of 1000 nm are reduced due to the high dielectric constant of alumina. A preferred proportion is 1.5% to 10% by mass.

[0080] like Figure 2 As shown, it can be confirmed that the alumina-based composition in the zirconium nitride powder 23 containing the alumina-based composition is partially attached to the surface of particles 23a (hereinafter referred to as "zirconium nitride particles 23a") that are mainly composed of zirconium nitride. However, at this stage, it cannot be confirmed whether the alumina-based composition 23b is contained inside the zirconium nitride particles 23a. Furthermore, although the surface of the zirconium nitride particles 23a without attached alumina-based composition is mostly exposed zirconium nitride, it may sometimes be a thin oxide layer of aluminum compound.

[0081] The presence or absence of alumina-based compositions on the particle surface was confirmed using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray diffraction (EDS). Specifically, a STEM (Thermo Fisher Scientific KK, trade name: Titan G2 ChemiSTEM) was used at magnifications ranging from 10,000x to 200,000x, allowing for the observation of 1 to 5 particles, under an accelerating voltage of 200 kV, to confirm the presence or absence of these compositions. Furthermore, within the same field of view, EDS (Thermo Fisher Scientific KK, trade name: Velox) was used to perform elemental mapping of aluminum, zirconium, oxygen, and nitrogen, and the presence or absence of alumina-based compositions and zirconium nitride was confirmed by distinguishing between them. In short, when observing the particle appearance, the contrast difference between aluminum and zirconium elements in the high-angle annular dark field (HAADF) image can also be used to distinguish between alumina-based compositions and zirconium nitride. Here, aluminum oxide (including Al2O3, α-alumina, θ-alumina, γ-alumina) and aluminum hydroxide (Al(OH)3) are examples of alumina-based compositions.

[0082] The aluminum content was determined using an inductively coupled plasma atomic emission spectrometer (SHIMADZU CORPORATION ICP spectrometer, trade name: ICPS-7510).

[0083] Furthermore, the BET specific surface area of ​​the zirconium nitride powder containing the alumina-based composition is 30 m². 2 / g~90m 2 / g. If the specific surface area of ​​the zirconium nitride powder is less than 30m². 2 If the concentration is / g, then when used as a black photoresist, pigment sedimentation may occur during long-term storage. If it exceeds 90m... 2 If the concentration is / g, then when used as a black pigment to form a patterned film, there is a problem of insufficient visible light shielding performance. A more preferable concentration is 30m. 2 / g~70m 2 / g. Based on the specific surface area described above, the average particle size, which is considered to be spherical, can be calculated using the following formula (6). The average particle size of the zirconium nitride particles of this embodiment, calculated based on the BET specific surface area, is 10 nm to 40 nm. In formula (6), L is the average particle size (μm), and ρ is the particle density (g / cm³). 3 S is the specific surface area of ​​the particle (m²). 2 / g).

[0084] L=6 / (ρ×S)(6)

[0085] In the zirconium nitride powder containing an alumina-based composition of this embodiment, the alumina-based composition exists in the form of partial adhesion to the surface of the zirconium nitride particles. As shown in Patent Document 2, if the surface of the zirconium nitride particles is completely covered with alumina, light with a long wavelength of 1000 nm is transmitted due to the high dielectric constant of alumina. On the other hand, as in the zirconium nitride powder containing an alumina-based composition of this embodiment, when alumina is partially adhered to the surface of the zirconium nitride particles, good moisture resistance is maintained while the shielding properties of zirconium nitride are preserved, thus exhibiting high light-shielding properties. Furthermore, as described above, the aluminum-containing powder acts as an aid in the aluminothermic reduction reaction, thus exhibiting high crystallinity and particle homogenization effects, and improving light transmittance in the ultraviolet region at a wavelength of 370 nm.

[0086] The zirconium nitride powder containing the alumina-based composition in this embodiment is further preferably characterized by a light transmittance X of 370 nm or more and a light transmittance Y of 1000 nm or less in the transmission spectrum of a dispersion of zirconium nitride powder containing the alumina-based composition at a concentration of 50 ppm. For example, the zirconium nitride powder containing the alumina-based composition is pulverized and dispersed in a propylene glycol monomethyl ether acetate (PGM-Ac) solvent as the dispersion medium using a bead mill (using zirconium dioxide beads with a diameter of 0.3 mm) to prepare a dispersion. To make the dispersion of particles in the dispersion more stable, an amine-based dispersant can be used, for example. The optical path length used to measure the light transmittance is 1 cm.

[0087] If the light transmittance X is less than 20%, when forming a patterned film as a black pigment, it will not be exposed to the bottom of the photoresist film, and undercutting of the patterned film is likely to occur. Furthermore, if the light transmittance Y exceeds 35%, the resulting patterned film will have insufficient light-shielding properties in the near-infrared region. More preferably, the light transmittance X is 25% or more, and even more preferably, the light transmittance Y is 30% or less. Considering the aforementioned inverse relationship between light transmittance X and light transmittance Y, the ratio X / Y of the zirconium nitride powder containing the alumina-based composition in this embodiment, specifically the ratio of light transmittance X at a wavelength of 370 nm to light transmittance Y at a wavelength of 1000 nm, is preferably 1.2 or more, and more preferably 1.3 or more. That is, with X / Y of 1.2 or more, ultraviolet light transmission is achieved, and undercutting of the patterned film is less likely to occur.

[0088] Furthermore, the final product, zirconium nitride powder containing an alumina-based composition, must be sufficiently dispersed to prevent particle aggregation. This can be achieved, for example, by using a polymeric dispersant with functional groups such as phosphate or amine, and by using a pulverizing medium such as zirconium dioxide beads for a specified dispersion period. As an indicator of dispersibility, examples include cases where secondary aggregates exceeding 200 nm are not detected in a dynamic scattering particle size analyzer (e.g., Microtrac, Inc., trade name: UPA; HORIBA, Ltd., trade name: SZ-100).

[0089] [Preparation of black dispersion]

[0090] A black dispersion is prepared by dispersing zirconium nitride powder containing an alumina-based composition in a solvent or monomeric compounds such as acrylic monomers or epoxy monomers.

[0091] Acrylic monomers are monomers containing a (meth)acryloyl group. A (meth)acryloyl group includes both acryloyl and methacryloyl groups. An acrylic monomer can be a monofunctional acrylic monomer having one (meth)acryloyl group in one molecule, or a polyfunctional acrylic monomer having two or more (meth)acryloyl groups in one molecule. It can also be a mixture of two or more of these.

[0092] Examples of monofunctional (meth)acrylic acid monomers include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, isodecanyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, isoamyl acrylate, tetrahydrofurfuryl (meth)acrylate, and isobornyl (meth)acrylate. Mixtures of two or more of these monomers are also possible.

[0093] Examples of difunctional (meth)acrylate monomers include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, and neopentyl triethylene glycol di(meth)acrylate. A mixture of two or more of these monomers may also be used.

[0094] Examples of polyfunctional (meth)acrylic acid monomers include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and trimethylolpropane tri(meth)acrylate. A mixture of two or more of these monomers may also be used.

[0095] Epoxy monomers are substances containing epoxy groups. Epoxy monomers can be monofunctional epoxy monomers with one epoxy group in a molecule, or polyfunctional epoxy monomers with two or more epoxy groups in a molecule. Examples of epoxy monomers include glycidyl ethers and alicyclic epoxy resins. A mixture of two or more of these can be used.

[0096] By adding the black dispersion, which serves as a monomer dispersion, to a polymer, a resin composition containing the aforementioned zirconium nitride particles is prepared, and a resin molded article is formed from this resin composition. Furthermore, the black dispersion, which serves as a monomer dispersion, also contains metal oxide particles and may further contain a plasticizer.

[0097] There are no particular limitations on the use of plasticizers. Examples include phosphate ester plasticizers such as tributyl phosphate and 2-ethylhexyl phosphate; phthalate ester plasticizers such as dimethyl phthalate and dibutyl phthalate; aliphatic-basic ester plasticizers such as butyl oleate and glyceryl monooleate; aliphatic diester ester plasticizers such as dibutyl adipate and di-2-ethylhexyl sebacate; diol ester plasticizers such as diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate; and oxyacid ester plasticizers such as methyl acetylated ricinoleate and tributyl acetylated citrate. Two or more of these plasticizers can be used in combination.

[0098] Other monomers can be further added to the black dispersion, which is the monomer dispersion. There are no particular limitations on these other monomers; examples include (meth)acrylic acid, (meth)acrylate and other (meth)acrylate monomers, styrene monomers such as styrene, vinyltoluene, and divinylbenzene, vinyl monomers such as vinyl chloride and vinyl acetate, urethane monomers such as urethane acrylates, and various polyols mentioned above, as well as other conventionally known monomers. Two or more of these monomers can be mixed. Furthermore, considering the dispersibility of zirconium nitride particles, the viscosity of the monomer dispersion is preferably set in the range of 10 Pa·s to 1000 mPa·s.

[0099] The dispersion of monomeric compounds, similar to the dispersion in solvents described below, can also be achieved using grinding methods with pulverizing media. Furthermore, although not essential, polymeric dispersants can be used to further improve dispersibility. Ideally, the molecular weight of the polymeric dispersant should be in the range of several thousand to tens of thousands.

[0100] Furthermore, functional groups that can be used as polymeric dispersants adsorbed onto pigments include secondary amines, tertiary amines, carboxylic acids, phosphoric acid, and phosphate esters, with tertiary amines and carboxylic acids being particularly effective. Two or more of these can be mixed. Adding a small amount of silane coupling agent instead of a polymeric dispersant is also effective in improving dispersibility. On the other hand, a black dispersion can be obtained by passing the mixture through a three-roll mill multiple times after planetary mixing.

[0101] Regarding black dispersions dispersed in solvents, the addition of polymeric dispersants is effective, similar to that for black dispersions dispersed in monomeric compounds. As with black dispersions dispersed in monomeric compounds, polymeric dispersants with molecular weights in the thousands to tens of thousands are effective, and tertiary amines and carboxylic acids are effective functional groups for these dispersants. Examples of solvents include isopropanol (IPA), butyl acetate (BA), and methyl ethyl ketone (MEK). Mixtures of these can also be used.

[0102] [Preparation of the black photosensitive composition]

[0103] A black composition is prepared by dispersing zirconium nitride powder containing an alumina-based composition as a black pigment in a dispersion medium and further mixing it with a resin. Examples of dispersion media include propylene glycol monomethyl ether acetate (PGM-Ac), methyl ethyl ketone (MEK), and butyl acetate (BA), and mixtures thereof can be used. Examples of resins include photosensitive acrylic resins and epoxy resins.

[0104] [Method for forming a patterned film of zirconium nitride powder containing an alumina-based composition as a black pigment]

[0105] A method for forming a patterned film, represented by a black matrix, using the aforementioned zirconium nitride powder as a black pigment will be described. First, a black dispersion is prepared by dispersing the zirconium nitride powder in a solvent. An amine-based dispersant is preferably used. Examples of solvents include propylene glycol monomethyl ether acetate (PGM-Ac), diethyl ketone, and butyl acetate. A photosensitive acrylic resin is added to this dispersion in a mass ratio of black pigment to resin of (10:90) to (80:20) and mixed to prepare a black photosensitive composition. Next, this black photosensitive composition is coated onto a substrate, and pre-baking is performed to evaporate the solvent, thereby forming a photoresist film. Then, the photoresist film is exposed to a predetermined pattern shape through a photomask, and developed using an alkaline developer to dissolve and remove the unexposed portions of the photoresist film. Finally, a predetermined black patterned film is preferably formed by post-baking.

[0106] Examples of substrates include glass, silicon, polyethylene terephthalate, polycarbonate, polyester, aromatic polyamide, polyamide-imide, and polyimide. Furthermore, the substrate can be pretreated with appropriate pretreatments such as chemical treatment with silane coupling agents, plasma treatment, ion plating, sputtering, vapor phase reaction, or vacuum evaporation, as needed. When coating the black photosensitive composition onto the substrate, appropriate coating methods such as spin coating, casting coating, or roll coating can be used. Regarding the coating thickness, based on the dried film thickness, it is typically 0.1 μm to 10 μm, preferably 0.2 μm to 7.0 μm, and more preferably 0.5 μm to 6.0 μm. In this embodiment, the radiation used when forming the patterned film is preferably electromagnetic waves with a wavelength in the range of 250 nm to 370 nm. The cumulative light intensity of the electromagnetic waves is preferably 10 J / m². 2 ~10,000J / m 2 .

[0107] Furthermore, the preferred alkaline developing solution is an aqueous solution of sodium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, or 1,5-diazabicyclo-[4.3.0]-5-nonene. Appropriate amounts of water-soluble organic solvents such as methanol and ethanol, and surfactants can also be added to the alkaline developing solution. After alkaline development, the product is typically washed with water. As a developing method, spray developing, immersion developing, and immersion (liquid-filled) developing methods are applicable, with the developing conditions preferably ranging from 5 to 300 seconds at room temperature. The patterned film thus formed is suitable for use in high-resolution liquid crystals, black matrices for organic ELs, light-shielding materials for image sensors, light-shielding materials for optical components, light-shielding filters, and IR cutoff filters. Furthermore, the black patterned film serves as an element constituting the black film. Specifically, the black film is obtained by having a support film and the black patterned film located on the support film.

[0108] Example

[0109] Next, embodiments and comparative examples of the present invention will be described in detail.

[0110] <Example 1>

[0111] With a specific surface area of ​​30m² 25 g of monoclinic zirconium dioxide powder was mixed with 0.3 g of aluminum powder (0.24 mol relative to zirconium dioxide) with an average particle size of 5 μm, 3.9 g of magnesium powder (4.0 mol relative to zirconium dioxide), and 2.3 g of magnesium oxide powder (1.4 mol relative to zirconium dioxide). The molar numbers in parentheses are proportions relative to 1 mol of zirconium dioxide. The BET specific surface area was determined using nitrogen as the adsorbate, as described later. The mixture was placed in a reaction vessel and calcined at 950 °C for 60 minutes under a nitrogen atmosphere. The calcined product was dispersed in 0.1 L of water, and 10% hydrochloric acid was gradually added. After washing at a pH above 1 and a temperature below 90 °C, the pH was adjusted to 7–8 with 2.5% ammonia and then filtered. The filtered solids were redispersed in 0.4 L of water, and again acid-washed as described above, adjusted to pH with ammonia, and then filtered. Thus, after repeating the pH adjustment twice based on acid washing and ammonia, the filter material was dispersed in ion-exchange water at a solid content of 5 g / L. After heating and stirring at 60°C and adjusting the pH to 7, it was filtered using a vacuum filtration device, washed with an equal volume of ion-exchange water, and dried in a hot air dryer at a set temperature of 120°C, thereby obtaining the final product powder. The manufacturing conditions of Example 1 are shown in Table 1 below.

[0112] [Table 1]

[0113]

[0114] <Examples 2-10 and Comparative Examples 3 and 4>

[0115] When manufacturing the powders of the final products of Examples 2-10 and Comparative Examples 3 and 4, the BET specific surface area of ​​the zirconium oxide (ZrO2) powder was the same as or modified as in Example 1, and the type, average particle size, and amount of aluminum-containing powder used as the aluminum source were the same as or modified as in Example 1. Furthermore, the addition ratio of metallic magnesium (Mg) powder and magnesium oxide (MgO) powder to zirconium oxide (ZrO2) powder, the calcination atmosphere, temperature, and time were the same as or modified as in Example 1, thus obtaining the powders of the final products of Examples 2-10 and Comparative Examples 3 and 4. These details are shown in Table 1 above. Furthermore, in Figure 2 The image shown is a scanning transmission electron microscope (STEM) photograph of the particles of Example 3. Figure 2 The image shows a zirconium nitride powder 23 containing an alumina-based composition, formed by the partial adhesion of a gray alumina-based composition 23b to the surface of black zirconium nitride particles 23a.

[0116] <Comparative Example 1>

[0117] In Comparative Example 1, the powder of the final product was obtained by the method of Example 1, which is based on claim 3 of Patent Document 1. An aluminum-free source was used, and the BET specific surface area was 30 m². 2 / g of monoclinic zirconium dioxide powder was used as the starting material.

[0118] Specifically, based on the BET method, the specific surface area is 30m². 2 7.4 g of monoclinic zirconium dioxide powder, 7.3 g of metallic magnesium powder with an average primary particle size of 150 μm, and 3.0 g of magnesium nitride powder with an average primary particle size of 200 nm were added and uniformly mixed using a reaction apparatus with a graphite boat embedded in a quartz glass tube. At this point, the amount of metallic magnesium added was 5.0 molars of zirconium dioxide, and the amount of magnesium nitride added was 0.5 molars of zirconium dioxide. The mixture was calcined at 700 °C for 60 minutes under a nitrogen atmosphere to obtain a calcined product. The calcined product was dispersed in 0.1 L of water, and 10% hydrochloric acid was gradually added. After washing at a pH above 1 and a temperature maintained below 90 °C, the pH was adjusted to 7-8 with 2.5% ammonia and then filtered. The filtered solids were redispersed in 0.4 L of water, and again subjected to acid washing in the same manner, followed by pH adjustment with ammonia and filtration. After repeating the pH adjustment process twice based on acid washing and ammonia water, the filter material was dispersed in ion-exchange water at a solid content of 5 g / L. After heating and stirring at 60°C and adjusting the pH to 7, it was filtered using a vacuum filtration device and washed with an equal amount of ion-exchange water. It was then dried in a hot air dryer at a set temperature of 120°C, thereby obtaining the final product powder.

[0119] <Comparative Example 2>

[0120] In Comparative Example 2, the powder of the final product was obtained by the method of Example 3, which is based on claim 4 of Patent Document 1.

[0121] 7.4 g of zirconium dioxide powder, identical to that in Example 1, was dispersed in ethanol. This mixture was then added to a silicate sol-gel solution (0.1522 g of silica) primarily composed of tetraethyl orthosilicate and mixed to prepare a slurry with a solid content of 30% by mass. The slurry was dried in a box dryer at 70°C for 120 minutes under atmospheric conditions to obtain zirconium dioxide powder coated with silica with an average primary particle size of 50 nm. This powder contained 3.0% by mass of silica (SiO2) in the zirconium dioxide. 8.8 g of magnesium metal powder with an average primary particle size of 300 μm and 2.1 g of magnesium nitride powder with an average primary particle size of 500 nm were added to 7.5 g of this zirconium dioxide powder and mixed uniformly as in Example 1. At this time, the amount of magnesium metal added was 6.0 moles of zirconium dioxide, and the amount of magnesium nitride added was 2.0 moles of zirconium dioxide. Zirconium nitride powder was then obtained using the same method as in Comparative Example 1.

[0122] <Comparative Example 5>

[0123] In Comparative Example 5, the powder of the final product was obtained by the method shown in Example 1, which is based on claim 2 of Patent Document 2. An aluminum hydroxide solution was used instead of aluminum hydroxide powder as the aluminum source.

[0124] Specifically, when the specific surface area of ​​BET is 30m² 2 7.4 g of monoclinic zirconium dioxide powder, 7.3 g of metallic magnesium powder with an average primary particle size of 150 μm, and 3.0 g of magnesium nitride powder with an average primary particle size of 200 nm were added and uniformly mixed using a reaction apparatus with a graphite boat embedded in a quartz glass tube. At this point, the amount of metallic magnesium added was 5.0 molars of zirconium dioxide, and the amount of magnesium nitride added was 0.5 molars of zirconium dioxide. The mixture was calcined at 700 °C for 60 minutes under a nitrogen atmosphere to obtain a calcined product. The calcined product was dispersed in 0.1 L of water, and 17.5% hydrochloric acid was gradually added. After washing at a pH above 1 and a temperature maintained below 90 °C, the pH was adjusted to 7-8 with 2.5% ammonia and then filtered. The filtered solids were redispersed in 0.4 L of water, and again acid-washed in the same manner, adjusted to pH with ammonia, and then filtered. After repeating the pH adjustment process twice based on acid washing and ammonia, the filter material was dispersed in ion-exchange water at a solid content of 5 g / L. After heating and stirring at 60°C and adjusting the pH to 7, it was filtered using a vacuum filtration device, washed with an equal amount of ion-exchange water, and dried in a hot air dryer at a set temperature of 120°C, thereby obtaining zirconium nitride powder.

[0125] The zirconium nitride powder was pulverized in water using a bead mill (using zirconium dioxide beads with a diameter of 0.3 mm), thereby obtaining a slurry containing zirconium nitride particles with an average primary particle size of 30 nm. To this pulverized zirconium nitride slurry (zirconium nitride powder (black pigment) concentration 10%), a 5% aluminum hydroxide solution (a solution of aluminum hydroxide dissolved in sodium hydroxide) was added at a ratio of 5% by mass of Al2O3 to 100% by mass of zirconium nitride. The pH of the slurry at this point was 10. Next, 17.5% hydrochloric acid was added dropwise to the slurry until the pH reached 5. As a result, aluminum hydroxide precipitated on the surface of the zirconium nitride particles. After repeated decantation and washing of the slurry, the filter cake (residue accumulated on the surface of the filter media) was filtered and recovered. The obtained filter cake was calcined at 300°C for 1 hour under a nitrogen atmosphere, thereby obtaining a powder of the final product with the particle surface coated with aluminum oxide.

[0126] The manufacturing conditions for Comparative Example 1, Comparative Example 2 and Comparative Example 5 are shown in Table 1 above.

[0127] <Comparative Experiment>

[0128] Powders of the final products from Examples 1-10 and Comparative Examples 1-5 were used as samples. The presence or absence of an alumina-based composition was confirmed from these samples, and the particle type was determined accordingly. The aluminum content was also measured. This confirmation and measurement were performed using the methods described above. Next, for these samples, (1) the BET specific surface area was measured; (2) the light transmittance X at a wavelength of 370 nm and the light transmittance Y at a wavelength of 1000 nm were read from the spectral curves, and the X / Y ratio was calculated. Furthermore, (3) the moisture resistance was measured. These results are shown in Table 2 below. In Table 2, "alumina" is referred to as "Al oxide".

[0129] (1) BET specific surface area: For all samples, the BET specific surface area was determined by the single-point BET1 method based on nitrogen adsorption using a specific surface area measuring device (manufactured by SIBATA SCIENTIFICTECHNOLOGY LTD., trade name SA-1100).

[0130] (2) Spectral curves of dispersions with a powder concentration of 50 ppm: For each sample of Examples 1-10 and Comparative Examples 1-5, these samples were placed in a circulating horizontal bead mill (medium: zirconium dioxide) and an amine dispersant was added, followed by dispersion treatment in propylene glycol monomethyl ether acetate (PGM-Ac) solvent. The obtained 15 dispersions were further diluted 100,000 times in propylene glycol monomethyl ether acetate (PGM-Ac) solvent, and the powder concentration was adjusted to 50 ppm. Using an instrument manufactured by Hitachi High-Tech Fielding Corporation, trade name: UH-4150, with an optical path length of 1 cm, the light transmittance of each sample in the diluted dispersion was measured in the range of wavelengths from 240 nm to 1300 nm, thereby obtaining the spectral curves. The light transmittance X at a wavelength of 370 nm near i-ray (365 nm) and the light transmittance Y at a wavelength of 1000 nm were read from the spectral curves. Figure 1 The figure shows three spectral curves of Example 1 and Comparative Examples 1 and 2.

[0131] X / Y was calculated based on the light transmittance X and light transmittance Y read from the spectral curves of each sample from Examples 1 to 10 and Comparative Examples 1 to 5.

[0132] (3) Moisture resistance: In order to confirm the effect of aluminum content, the moisture resistance of all samples was checked.

[0133] Amine-based dispersants were added to the particles of Examples 1-10 and Comparative Examples 1-5, and dispersions were prepared by dispersing them in propylene glycol monomethyl ether acetate (PGM-Ac) solvent. Acrylic resin was added to this dispersion at a mass ratio of black pigment to resin of 5:5, and the mixture was stirred to prepare a black composition. This black composition was spin-coated onto a glass substrate and held at 250°C for 30 minutes, thereby obtaining a dried coating film with a thickness of 1 μm. The volume resistivity of the coating films was measured.

[0134] The prepared coating samples were placed in a constant temperature and humidity chamber set at 60°C and 90% for 100 hours to conduct a high-temperature humidity resistance test. The volume resistivity of each film was measured before and after the test using an instrument manufactured by Mitsubishi Chemical Analytech Co., Ltd., under the trade name Hiresta (model: MCP-HT800), at a voltage of 1000V. Regarding the moisture resistance of the samples, if the ratio R of the difference between the volume resistivity of each film before and after the test, calculated according to the following formula (7), is less than 50%, it is considered to have moisture resistance and is judged as "good". Furthermore, if the difference is 50% or more, it is considered to have no moisture resistance and is judged as "poor".

[0135] R = [(Volume resistivity of coating after test - Volume resistivity of coating before test) / Volume resistivity of coating before test] × 100 (7)

[0136] [Table 2]

[0137]

[0138] <Evaluation>

[0139] Table 2 clearly confirms that, in Comparative Examples 1 and 2, STEM observation of the final product powder revealed the absence of aluminum compounds on the surface of these zirconium nitride particles. Electron beam diffraction analysis of the particles' interior also showed the absence of alumina. Since the particles were not coated with alumina and did not contain any alumina-based compositions, their moisture resistance was poor. No improvement in crystallinity or particle fineness and homogenization was observed due to the aluminothermic reduction reaction containing aluminum compounds. The light transmittance X at 370 nm was 18.0% in Comparative Example 1 and 19.5% in Comparative Example 2, both below 20%, indicating low ultraviolet transmittance. The X / Y values ​​were 0.90 and 0.78, respectively.

[0140] In Comparative Example 3, the amount of aluminum powder added as the aluminum-containing powder was excessive, reaching 25% by mass (0.85 moles relative to zirconium oxide), resulting in an excessive aluminum content in the final product powder, reaching 17.0% by mass. STEM observation of the final product powder confirmed that the surface of the zirconium nitride particles was largely coated with aluminum compounds. Therefore, although the powder exhibited good moisture resistance, the excess alumina compounds resulted in light transmittance, leading to a light transmittance (Y) of 43.0% at a wavelength of 1000 nm and a X / Y ratio of 0.93, which was lower than 1.2. Furthermore, the BET specific surface area was excessively large, reaching 100 m². 2 / g, therefore the powder of the final product is not sufficiently dispersed, and the shielding effect of visible light will also be reduced.

[0141] In Comparative Example 4, the amount of aluminum powder added as the aluminum-containing powder was too low, reaching 1.5% by mass (0.04 moles relative to zirconium oxide), and the proportion of aluminum in the final product powder was too low, reaching 0.7% by mass. Therefore, STEM observation of the final product powder confirmed that a small amount of aluminum compound was attached to the surface of the zirconium nitride particles. Furthermore, the powder did not exhibit the effects of increased crystallinity and finer particle uniformity resulting from the aluminothermic reduction reaction containing aluminum compounds; the light transmittance X at a wavelength of 370 nm was 19.0%, lower than 20%, and the X / Y value was 1.06, lower than 1.2, indicating low ultraviolet transmittance. Moreover, the moisture resistance was poor due to the low proportion of the alumina-based composition.

[0142] In Comparative Example 5, zirconium nitride powder was prepared by adding aluminum hydroxide solution to zirconium nitride slurry. STEM observation of the final product powder confirmed that the surface of the zirconium nitride particles was coated with aluminum oxide. While the powder exhibited good moisture resistance, the complete coating of the particles with aluminum oxide hindered the light-shielding properties of the zirconium nitride, resulting in an X / Y value of 0.95, which is lower than 1.2.

[0143] In contrast, the final products of Examples 1-10 were zirconium nitride powders containing an alumina-based composition. STEM observation of these final product powders confirmed that all zirconium nitride particles had aluminum compounds locally attached to their surfaces. Electron beam diffraction analysis showed that the aluminum compounds existed as amorphous alumina within the powders of all final products. Furthermore, all final product powders exhibited good moisture resistance, and the aluminum content was between 1% and 15% by mass. Therefore, the final products of Examples 1-10 were deemed to meet the requirements of the first aspect of the present invention, possessing not only high visible light shielding performance but also ultraviolet light transmission, which is beneficial for patterning.

[0144] Especially BET specific surface area is 30m² 2 / g~90m 2 The final products of Examples 1 to 9, which have a light transmittance X of 370 nm or more within the range of / g, a light transmittance Y of 1000 nm of less than 35%, and a ratio X / Y of 370 nm light transmittance X to 1000 nm light transmittance Y of more than 1.2, are determined to satisfy the requirements of the second aspect of the present invention. They have higher light-shielding performance for visible light and transmit ultraviolet light, which is more conducive to patterning.

[0145] Industrial availability

[0146] The zirconium nitride powder containing an alumina-based composition of the present invention can be used in high-precision liquid crystals, black matrices for organic EL, light-shielding materials for image sensors, light-shielding materials for optical components, light-shielding filters, IR cut-off filters, black films, etc., and therefore its industrial application is feasible.

Claims

1. A zirconium nitride powder containing an alumina-based composition, characterized in that, The zirconium nitride powder containing the alumina-based composition is obtained by locally adhering the alumina-based composition to the surface of particles mainly composed of zirconium nitride. When the total amount of the zirconium nitride powder containing the alumina-based composition is set to 100% by mass, the zirconium nitride powder containing the alumina-based composition contains aluminum in a proportion exceeding 1% by mass and less than 15% by mass, and has a specific surface area of ​​30 m² as determined by the BET method. 2 / g~90m 2 / g, When measuring the transmission spectrum of the dispersion prepared in a manner where the concentration of zirconium nitride powder containing the alumina-based composition is 50 ppm, the light transmittance X at a wavelength of 370 nm is 20% or more, the light transmittance Y at a wavelength of 1000 nm is 35% or less, and the ratio of the light transmittance X at a wavelength of 370 nm to the light transmittance Y at a wavelength of 1000 nm, X / Y, is 1.2 or more.

2. The zirconium nitride powder containing an alumina-based composition according to claim 1, wherein, When the total amount of zirconium nitride powder containing the alumina-based composition is set to 100% by mass, the aluminum content is 1.1% by mass or more, and when the transmission spectrum of the dispersion prepared with a concentration of 50 ppm of zirconium nitride powder containing the alumina-based composition is measured, the light transmittance X at a wavelength of 370 nm is 23% or more.

3. A method for manufacturing zirconium nitride powder containing an alumina-based composition, comprising: after mixing zirconium powder, aluminum-containing powder at 0.05 to 0.8 moles of the zirconium powder, metallic magnesium powder at 2.0 to 6.0 moles of the zirconium powder, and magnesium oxide powder at 0.3 to 5.0 moles of the zirconium powder to obtain a mixture, calcining the mixture under a nitrogen atmosphere at a temperature exceeding 900°C and below 1100°C for 60 to 180 minutes, thereby reducing the zirconium powder to manufacture the zirconium nitride powder containing an alumina-based composition as described in claim 1 or 2.

4. The method for manufacturing zirconium nitride powder containing an alumina-based composition according to claim 3, wherein, The aluminum-containing powder is any one or more of metallic aluminum, aluminum oxide, aluminate compounds, and aluminum hydroxide.

5. A black dispersion, said black dispersion is formed by dispersing zirconium nitride powder containing an alumina-based composition as described in claim 1 or 2 in a solvent or monomer compound.

6. A black photosensitive composition comprising zirconium nitride powder containing an alumina-based composition as described in claim 1 or 2 as a black pigment.

7. A black patterned film, said black patterned film being obtained using the black photosensitive composition of claim 6.

8. A black matrix obtained using the black patterned film of claim 7.

9. A light-shielding material obtained using the black patterned film of claim 7.

10. A light-shielding filter, said light-shielding filter being obtained using the black patterned film of claim 7.

11. A black film comprising a support film and a black patterned film of claim 7 located on the support film.

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