Zirconium nitride powder containing an aluminum oxide-based composition and method for producing the same

Abstract

To provide aluminum oxide-based composition containing zirconium nitride powder exhibiting relatively high light shielding property in a near infrared region of a wavelength of 1,000 nm, excellent patterning characteristics, excellent visible light shielding property, and good moisture resistance, upon forming a black patterning film as a black pigment.SOLUTION: Provided is the aluminum oxide-based composition containing zirconium nitride powder in which an aluminum oxide-based composition derived from a water-soluble aluminum compound is adhered to a part of a powder surface, aluminum is contained at a ratio of more than 1 mass% and 15 mass% or less in a case where the total amount of powder is defined as 100 mass%, and a specific surface area measured by a BET method ranges from 30 to 90 m2 / g..SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] This type of black pigment is dispersed in a photosensitive resin to prepare a black photosensitive composition. This composition is applied to a substrate to form a photoresist film, and the photoresist film is exposed by photolithography to form a patterning film, thereby being used for a black matrix of an image forming element such as a color filter of a liquid crystal display. Since conventional carbon black as a black pigment has conductivity, it is not suitable for applications that require insulation.

[0003] Conventionally, a zirconium nitride powder and a method for producing the same have been disclosed in which a high-resolution patterning film is formed when forming a black patterning film as a black pigment and the formed patterning film has high light-shielding performance (see Patent Document 1 (Claim 1, Claim 3, Paragraph

[0007] )). This zirconium nitride powder has a specific surface area measured by the BET method of 20 to 90 m 2 / g, and in the X-ray diffraction profile, while having a peak of zirconium nitride, it does not have a peak of zirconium dioxide, a peak of lower-order zirconium oxide, and a peak of lower-order oxynitride zirconium, and in the dispersion liquid transmission spectrum 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 12% or less, and the light transmittance X at 370 nm with respect to the light transmittance Y at 550 nm (X / Y) is 2.5 or more.

[0004] The zirconium nitride powder shown in Patent Document 1 is produced by reducing zirconium dioxide powder or zirconium dioxide powder coated with silica, metallic magnesium powder, and magnesium nitride powder, such that the metallic magnesium is in a proportion of 2.0 to 6.0 moles per mole of zirconium dioxide and the magnesium nitride is in a proportion of 0.3 to 3.0 moles per mole of zirconium dioxide to obtain a mixture, and then firing the mixture at a temperature of 650 to 900°C in an atmosphere of nitrogen gas alone, or a mixed gas of nitrogen gas and hydrogen gas, or a mixed gas of nitrogen gas and ammonia gas.

[0005] However, when the zirconium nitride powder shown in Patent Document 1 is left in a high-temperature and high-humidity atmosphere of, for example, 80°C and 85%, oxidation of the zirconium nitride surface progresses, resulting in a problem that when a patterning film is formed using this zirconium nitride powder, the moisture resistance of the film is insufficient and the light-shielding performance deteriorates.

[0006] To solve this problem, heretofore, a zirconium nitride powder and a method for producing the same have been disclosed, which can improve compatibility with an acrylic resin or the like and, in combination with gas barrier properties, also improve moisture resistance (see Patent Document 2 (Claims 1, 2, paragraph

[0006] )). Further, a powder for forming a black light-shielding film and a method for producing the same have been disclosed, which form a black light-shielding film having excellent ultraviolet transmittance and high-resolution patterning characteristics as a black pigment and the formed black light-shielding film has high light-shielding performance and high weather resistance (see Patent Document 3 (Claims 1, 2, paragraph

[0010] , paragraph

[0033] )).

[0007] The zirconium nitride powder shown in Patent Document 2 is zirconium nitride powder coated with alumina, having a volume resistivity of 1×10 6 Ω·cm or more, a coating amount of alumina of 1.5 to 9% by mass based on 100% by mass of zirconium nitride, and an isoelectric point of 5.7 or more.

[0008] The method for producing zirconium nitride powder disclosed in Patent Document 2 includes a step of pulverizing zirconium nitride powder 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 so that the mass ratio of zirconium nitride powder to aluminum oxide is in the range of (100:1.5) to (100:15), a step of adding an acid to the zirconium nitride slurry to which the aluminum compound solution has been added to adjust the pH of the zirconium nitride slurry and deposit the aluminum compound on the surface of the zirconium nitride powder to coat the zirconium nitride powder with the aluminum compound, a step of washing and then recovering the zirconium nitride powder coated with the aluminum compound, and a step of obtaining zirconium nitride powder coated with aluminum oxide by holding the recovered zirconium nitride powder coated with the aluminum compound at a temperature of 60°C to 200°C for 1 hour to 24 hours in an air or nitrogen atmosphere and firing it.

[0009] On the other hand, the powder for forming a black light-shielding film disclosed in Patent Document 3 has a specific surface area measured by the BET method of 20 to 90 m 2 / g, is a powder for forming a black light-shielding film containing zirconium nitride as a main component and containing magnesium and / or aluminum. When containing magnesium, the content ratio of magnesium is 0.01 to 1.0% by mass with respect to 100% by mass of the powder for forming a black light-shielding film. When containing aluminum, the content ratio of aluminum is 0.01 to 1.0% by mass with respect to 100% by mass of the powder for forming a black light-shielding film.

[0010] The method for producing a powder for forming a black light-shielding film disclosed in Patent Document 3 involves mixing zirconium dioxide powder, metallic magnesium powder, magnesium oxide powder or magnesium nitride, and aluminum oxide powder or aluminum nitride powder, such that the metallic magnesium is 25 to 150% by mass based on 100% by mass of the zirconium dioxide, the magnesium oxide is 15 to 500% by mass based on 100% by mass of the zirconium dioxide, and the aluminum oxide or aluminum nitride is 0.02 to 5.0% by mass based on 100% by mass of the zirconium dioxide. The resulting mixed powder is then fired at a temperature of 650 to 900°C in an atmosphere of pure nitrogen gas, a mixed gas atmosphere of nitrogen gas and hydrogen gas, a mixed gas atmosphere of nitrogen gas and ammonia gas, or an atmosphere of nitrogen gas and an inert gas, thereby reducing the mixed powder to produce a powder for forming a black light-shielding film.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0012] In recent years, in optical elements such as image sensors, there has been an increasing need to shield the near-infrared region around a wavelength of 1000 nm for noise suppression, and the demand for films that can shield not only the conventional visible light region but also this near-infrared region has been increasing.

[0013] However, although the zirconium nitride powder coated with alumina shown in Patent Document 2 can improve the compatibility with an acrylic resin or the like, and can also improve the moisture resistance in combination with the gas barrier property, there is a problem that the light shielding property in the near-infrared region with a wavelength of 1000 nm cannot be increased when forming a black patterning film as a black pigment. The reason is that the surface of the zirconium nitride particles is coated with alumina, and for the purpose of suppressing the sedimentation of the powder when used as a resist, zirconium nitride was pulverized in the initial stage of production, and the BET specific surface area of the zirconium nitride powder was made finer than 90 m 2 / g (with an average particle size of less than 10 nm), resulting in a decrease in crystallinity.

[0014] In addition, the powder for forming a black light-shielding film shown in Patent Document 3 has zirconium nitride as a main component and contains aluminum. When the content ratio of aluminum is 1.0% by mass or less with respect to 100% by mass of the powder for forming a black light-shielding film. Although Patent Document 3 states that when it exceeds 1.0% by mass, the light-shielding performance of the black light-shielding film deteriorates, when aluminum is used as a reducing agent for zirconium oxide in the thermite process, even if the content of aluminum is increased, the visible light shielding property of the film is not deteriorated, the crystallinity of the zirconium nitride powder is kept high without being lowered, and the transmittance in the ultraviolet region is not deteriorated without coarsening the zirconium nitride powder. The inventors have found this and reached the present invention. In addition, the inventors have found that when aluminum oxide is simply mixed with zirconium oxide powder, metal magnesium powder, and magnesium oxide powder and fired as in the manufacturing method of the powder for forming a black light-shielding film shown in Patent Document 3, the thermite reduction reaction by aluminum hardly occurs, and the present invention has been reached.

[0015] An object of the present invention is to provide a zirconium nitride powder containing an aluminum oxide-based composition that has relatively high light shielding property in the near-infrared region with a wavelength of 1000 nm, excellent patterning property and visible light shielding property, and good moisture resistance when forming a black patterning film as a black pigment.

Means for Solving the Problems

[0016] The first aspect of the present invention is that an aluminum oxide-based composition derived from a water-soluble aluminum compound is partially adhered to the powder surface. When the total amount of the powder is 100% by mass, it contains aluminum at a ratio exceeding 1% by mass and not exceeding 15% by mass, and the specific surface area measured by the BET method is 30 m 2 / g to 90 m 2 / g. It is a zirconium nitride powder containing an aluminum oxide-based composition, characterized by this.

[0017] The second aspect of the present invention is an invention based on the first aspect. In the dispersion transmission spectrum with a powder concentration of 50 ppm, the light transmittance X at 370 nm is 20% or more, the light transmittance Y at 1000 nm is 35% or less, and the light transmittance X at 370 nm (X / Y) with respect to the light transmittance Y at 1000 nm is 1.1 or more. It is a zirconium nitride powder containing an aluminum oxide-based composition.

[0018] The third aspect of the present invention is a method for producing a zirconium nitride powder containing an aluminum oxide-based composition according to the first or second aspect. First, zirconium oxide powder coated with an aluminum oxide-based composition, metallic magnesium powder 2.0 to 6.0 times the molar amount of the zirconium oxide, and magnesium oxide powder 0.3 to 5.0 times the molar amount of the zirconium oxide are mixed to obtain a mixture. Then, the mixture is calcined in a nitrogen gas atmosphere at a temperature of 700°C to 1100°C for 30 minutes to 180 minutes by the thermite method, thereby reducing the zirconium oxide powder coated with the aluminum oxide-based composition.

[0019] The fourth aspect of the present invention is an invention based on the third aspect, wherein the zirconium oxide powder coated with the aluminum oxide-based composition is obtained by adding and mixing a water-soluble aluminum compound to a zirconium oxide slurry in which zirconium oxide powder is dispersed in water to obtain a mixed solution, adding and mixing an alkali or an acid to the mixed solution, holding the mixture at a temperature of room temperature to 80 ° C for at least 60 minutes, and then subjecting the mixed solution to solid-liquid separation and drying, which is a method for producing zirconium nitride powder containing an aluminum oxide-based composition.

[0020] The fifth aspect of the present invention is an invention based on the fourth aspect, wherein the water-soluble aluminum compound is an aluminum compound that becomes acidic when dissolved in water, and it is a method for producing zirconium nitride powder containing an aluminum oxide-based composition in which an alkali is added and mixed to the mixed solution.

[0021] The sixth aspect of the present invention is an invention based on the fourth aspect, wherein the water-soluble aluminum compound is an aluminum compound that becomes alkaline when dissolved in water, and it is a method for producing zirconium nitride powder containing an aluminum oxide-based composition in which an acid is added and mixed to the mixed solution.

[0022] The seventh aspect of the present invention is a black dispersion in which the zirconium nitride powder containing the aluminum oxide-based composition according to the first or second aspect is dispersed in a solvent or a monomer compound.

[0023] The eighth aspect of the present invention is a black photosensitive composition containing the zirconium nitride powder containing the aluminum oxide-based composition according to the first or second aspect as a black pigment.

[0024] The ninth aspect of the present invention is a black patterning film obtained by using the black photosensitive composition according to the eighth aspect.

[0025] The tenth aspect of the present invention is a black matrix obtained by using the black patterning film according to the ninth aspect.

[0026] The 11th aspect of the present invention is a light-shielding material obtained using the black patterning film of the 9th aspect.

[0027] The 12th aspect of the present invention is a light-shielding filter obtained using the black patterning film of the 9th aspect.

[0028] The 13th aspect of the present invention is a black film including a support film and the black patterning film of the 9th aspect on the support film.

Advantages of the Invention

[0029] The zirconium nitride powder containing an aluminum oxide-based composition according to the 1st aspect of the present invention has an aluminum oxide-based composition derived from a water-soluble aluminum compound partially adhering to the powder surface. When the total amount of the powder is 100% by mass, it contains aluminum at a ratio exceeding 1% by mass and not exceeding 15% by mass, and the specific surface area measured by the BET method is 30 m 2 / g to 90 m 2 / g. Different from the zirconium nitride powder coated with alumina shown in Patent Document 2, the zirconium nitride powder containing an aluminum oxide-based composition of the present invention has a BET specific surface area of 30 m 2 / g to 90 m 2 / g. Even if it is a fine powder, its crystallinity is kept high, so the light transmittance in the ultraviolet region with a wavelength of 370 nm is high, and the light shielding property (low light transmittance) in the near-infrared region with a wavelength of 1000 nm is high.

[0030] Also, different from the powder for forming a black light-shielding film shown in Patent Document 3, even if the aluminum content is in the ratio exceeding 1% by mass and not exceeding 15% by mass, the powder is produced by the thermite method, and since aluminum is used as a reducing agent for zirconium oxide, the moisture resistance of the powder is improved without reducing the visible light shielding property of the formed film. Also, the crystallinity of the zirconium nitride powder is kept high without being reduced, and the transmittance in the ultraviolet region is not deteriorated without coarsening the zirconium nitride powder.

[0031] In addition, this aluminum oxide-based composition-containing zirconium nitride powder has a BET specific surface area of 30 m 2 / g or more, so it has the effect of suppressing sedimentation when used as a resist, and 90 m 2 / g or less, so it has the effect of having sufficient visible light shielding properties.

[0032] In the aluminum oxide-based composition-containing zirconium nitride powder according to the second aspect of the present invention, further, in the dispersion transmission spectrum with a powder concentration of 50 ppm, the light transmittance X at 370 nm is 20% or more, and the light transmittance Y at 1000 nm is 35% or less. Also, since X / Y is 1.1 or more, it has the characteristic of transmitting ultraviolet rays more. As a result, when forming a black patterning film as a black pigment, a higher-resolution patterning film can be formed, and moreover, the formed patterning film has higher visible light shielding performance.

[0033] In the method for producing aluminum oxide-based composition-containing zirconium nitride powder according to the third aspect of the present invention, in the method shown in Patent Document 2, an aluminum compound was added and mixed to a zirconium nitride slurry to prepare zirconium nitride powder coated with alumina, and then this was fired to produce zirconium nitride powder coated with alumina. In contrast, a water-soluble aluminum compound was added and mixed to a zirconium oxide slurry to prepare zirconium oxide powder coated with an aluminum oxide-based composition. After that, this powder, metal magnesium powder, and magnesium oxide powder were mixed at a predetermined ratio, and an aluminum oxide-based composition-containing zirconium nitride powder was produced by a thermite reduction reaction, so that the aluminum oxide-based composition partially adheres to the surface of the powder. Also, unlike the method for producing the black light-shielding film-forming powder shown in Patent Document 3, instead of simply mixing aluminum oxide with zirconium oxide powder, magnesium metal powder, and magnesium oxide powder, zirconium oxide powder coated with an aluminum oxide-based composition is mixed with magnesium metal powder and magnesium oxide powder, and the mixed powder is fired. As a result, the thermite reduction reaction with aluminum is likely to occur and the thermite reduction reaction further proceeds. This is presumably because the aluminum oxide-based composition adheres closely to the starting zirconium oxide raw material. Although it is confirmed that the aluminum oxide-based composition partially adheres to the surface of the zirconium nitride powder, it is not possible to analyze at this stage whether it is contained inside the zirconium nitride powder.

[0034] In the production method of Patent Document 2, for the purpose of coating the zirconium nitride powder with alumina, the starting zirconium nitride powder was pulverized so that the BET specific surface area of the zirconium nitride powder exceeded 90 m 2 / g (with an average particle size of less than 10 nm), thereby reducing the crystallinity of the zirconium nitride by pulverization. On the other hand, in the method of the third aspect of the present invention, since the zirconium nitride powder is not pulverized and the aluminum oxide-based composition adhering to the powder surface contributes to the thermite reduction reaction of zirconium oxide, the crystallinity of the zirconium nitride powder containing the aluminum oxide-based composition is not reduced and can be kept high.

[0035] Although the detailed mechanism of the thermite reduction reaction is unknown, by using zirconium oxide coated with an aluminum oxide-based composition (hereinafter sometimes referred to as coated zirconium oxide) as the reaction material, it is expected that the following side reactions will occur in the thermite reduction reaction, and it is presumed that good optical properties can be obtained by the effect thereof. Here, the "aluminum oxide-based composition" refers to a composition in which alumina (Al2O3), aluminum hydroxide (Al(OH)3), etc. are mixed.

[0036] When the above aluminum oxide-based composition is alumina, the reduction of this alumina by magnesium is represented by the following formula (1). Al2O3 + 3Mg → 2Al + 3MgO (1) The reduction of zirconium oxide by aluminum (Thermit reduction reaction) is represented by the following formula (2). 4Al + 3ZrO2 → 2Al2O3 + 3Zr (2) The nitriding reaction of metallic zirconium is represented by the following formula (3). Zr + 1 / 2N2 → ZrN (3) As a result of the sequential progression of the reactions shown in the above formulas (1) to (3), the reaction product becomes a mixture of zirconium nitride and an aluminum oxide-based compound.

[0037] Like metallic magnesium, metallic aluminum undergoes a Thermit reduction reaction at high temperatures, but the reaction is slower and longer than that of magnesium. Therefore, the zirconium nitride obtained as a reaction product has a small particle size with excellent uniformity and is considered to contribute particularly to the improvement of transmittance in the ultraviolet region. It has been confirmed that the aluminum oxide-based composition partially adheres to the surface of the zirconium nitride powder, but it is not possible to analyze whether it is contained inside the zirconium nitride powder at this stage.

[0038] In the production method of the fourth aspect of the present invention, an alkali or an acid is added and mixed to a mixed solution obtained by adding and mixing a water-soluble aluminum compound to a zirconium oxide slurry, and the mixture is aged under predetermined conditions. Then, the mixed solution is subjected to solid-liquid separation and dried, whereby zirconium oxide powder coated with an aluminum oxide-based composition is produced. Therefore, the aluminum oxide-based composition can be uniformly coated on the surface of the zirconium oxide powder. In the Thermit reduction reaction in the next step, the aluminum oxide-based composition partially adheres to the powder surface. It is not possible to analyze whether the aluminum oxide-based composition is contained inside the powder at this stage.

[0039] In the production method according to the fifth aspect of the present invention, when an aluminum compound that becomes acidic when dissolved in water is used as the water-soluble aluminum compound, an alkali can be added to and mixed with the mixed solution to perform a neutralization reaction.

[0040] In the production method according to the sixth aspect of the present invention, when an aluminum compound that becomes alkaline when dissolved in water is used as the water-soluble aluminum compound, an acid can be added to and mixed with the mixed solution to perform a neutralization reaction.

[0041] In the black dispersion according to the seventh aspect of the present invention, the zirconium nitride powder containing the aluminum oxide-based composition according to the first or second aspect is dispersed in a solvent or a monomer compound, so that zirconium nitride has the characteristics of transmitting ultraviolet rays and shielding visible light. As a result, this black dispersion is suitably used as a material for forming a black patterning film.

[0042] According to the black photosensitive composition according to the eighth aspect of the present invention, since it contains zirconium nitride powder containing an aluminum oxide-based composition as a black pigment, if a black patterning film is formed using this composition, the ultraviolet transmittance is high, so a high-resolution patterning film can be formed even if the amount of the photoinitiator used is reduced.

[0043] The black patterning film according to the ninth aspect of the present invention has high resolution and high shielding performance for visible light and light in the near-infrared region.

[0044] The black matrix according to the tenth aspect of the present invention is obtained by using the above black patterning film, and thus has a fine pattern.

[0045] The light-shielding material according to the eleventh aspect of the present invention, the light-shielding filter according to the twelfth aspect, and the black film according to the thirteenth aspect are obtained by using the above black patterning film, and thus have high shielding performance for visible light and light in the near-infrared region.

Brief Description of the Drawings

[0046]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0047] Next, a mode for carrying out the present invention will be described.

[0048] 〔Method for Manufacturing Zirconium Nitride Powder Containing Aluminum Oxide-Based Composition〕 The characteristic point of the method for manufacturing zirconium nitride powder containing an aluminum oxide-based composition of the present embodiment lies in using zirconium oxide powder coated with an aluminum oxide-based composition. For this reason, first, a method for manufacturing zirconium oxide powder coated with an aluminum oxide-based composition will be described.

[0049] 〔Method for Manufacturing Zirconium Oxide Powder Coated with Aluminum Oxide-Based Composition〕 As shown in Fig. 3, first, zirconium oxide powder 11 is prepared, and water 12 is added thereto and mixed to prepare a zirconium oxide slurry 13 such that the concentration of zirconium oxide in the slurry is in the range of 1 mass% to 20 mass%. Here, the zirconium oxide powder 11 is zirconium dioxide (ZrO2) powder. In order to obtain zirconium nitride powder containing an aluminum oxide-based composition having a BET specific surface area of 30 m 2 / g to 90 m 2 / g, the zirconium oxide powder 11 preferably has an average particle diameter of 500 nm or less in terms of spherical conversion from the measured value of the BET specific surface area. From the viewpoint of ease of handling of the powder, the average particle diameter is 10 nm or more (BET specific surface area 105 m 2less than / g) and 500 nm or less (BET specific surface area of 2 m 2 / g or more) is preferred.

[0050] As the zirconium oxide powder 11 of the present embodiment, for example, powders of zirconium dioxide such as monoclinic zirconium dioxide, cubic zirconium dioxide, yttrium-stabilized zirconium dioxide, etc. can all be used. However, from the viewpoint of increasing the production rate of zirconium nitride powder, monoclinic zirconium dioxide powder is preferred. Hafnium is usually contained in zirconium oxide as an unavoidable impurity at about 2% by mass, but at a level of 2% by mass, it has no effect on the optical properties.

[0051] Next, a water-soluble aluminum compound 14 is added to and mixed with the zirconium oxide slurry 13 to obtain a mixed solution 15. Before mixing with the zirconium oxide slurry 13, it is preferable that the water-soluble aluminum compound 14 is dissolved in water. Water-soluble aluminum compounds 14 include those that become acidic when dissolved in water and those that become alkaline. Examples of aluminum compounds that become acidic when dissolved in water include aluminum chloride compounds such as anhydrous aluminum chloride and aluminum chloride hexahydrate, aluminum nitrate, and aluminum sulfate. Examples of aluminum compounds that become alkaline when dissolved in water include alkali metal aluminates such as sodium aluminate, potassium aluminate, and lithium aluminate, and aluminum hydroxide.

[0052] The water-soluble aluminum compound 14 is added in a ratio of 2% to 30% in terms of aluminum oxide (Al2O3) conversion with respect to 100% by mass of zirconium oxide (ZrO2) in order to obtain a zirconium nitride powder containing an aluminum oxide-based composition in which the aluminum content of the final product exceeds 1% by mass and is 15% by mass or less.

[0053] Next, an alkali or an acid 16 is added to and mixed with the obtained mixed solution 15 to adjust the pH to 6 - 7, causing a neutralization reaction to obtain aluminum hydroxide. Neutralizing the mixed solution is to precipitate aluminum ions dissolved in water as hydroxides and coat the surface of the zirconium dioxide powder. Here, as a neutralizing agent for causing the neutralization reaction, when the water-soluble aluminum compound 14 is an aluminum chloride compound that becomes acidic when dissolved in water, an alkali such as aqueous ammonia or caustic soda is used. On the other hand, when the water-soluble aluminum compound 14 is an aluminum compound that becomes alkaline when dissolved in water, an acid such as hydrochloric acid, nitric acid, or sulfuric acid is used. An example of the reaction formula when using aqueous ammonia in the following formula (4) and an example of the reaction formula when using hydrochloric acid in formula (5) are shown respectively. AlCl3 + 3NH4OH → Al(OH)3 + 3NH4Cl (4) NaAlO2 + HCl + H2O → Al(OH)3 + NaCl + H2↑ (5)

[0054] The neutralization reaction caused by adding and mixing an alkali or an acid 16 to the mixed solution 15 is carried out at a temperature of room temperature to 80°C for a maximum of 60 minutes, preferably 10 minutes to 40 minutes. This is because the reactions shown in the above (4) and (5) are carried out sufficiently. After the neutralization reaction is carried out, the liquid is decanted to remove the supernatant, and after the precipitate is filtered, it is dried at a temperature of 100°C to 120°C for 10 hours to 12 hours. Thereby, zirconium dioxide powder 17 coated with an aluminum oxide-based composition is obtained. As described above, this aluminum oxide-based composition is a composition in which alumina (Al2O3), aluminum hydroxide (Al(OH)3), etc. are mixed.

[0055] [Mixing of ZrO2 powder coated with an aluminum oxide-based composition, metal Mg powder, and MgO powder] Subsequently, zirconium oxide powder (ZrO₂ powder) 17 coated with the obtained aluminum oxide-based composition is mixed with metallic magnesium powder (metallic Mg powder) 18 and magnesium oxide powder (MgO powder) 19 to obtain a mixture 20. These mixing ratios are determined in order to sufficiently reduce the coated zirconium oxide powder 17 to obtain a zirconium nitride powder containing the aluminum oxide-based composition of the final product. Specifically, per 1 mol of zirconium oxide powder, metallic magnesium powder 18 is mixed at a ratio of 2.0 to 6.0 times the molar amount, and magnesium oxide powder 19 is mixed at a ratio of 0.3 to 5.0 times the molar amount.

[0056] [metallic magnesium powder] If the particle size of metallic magnesium powder 18 is too small, the reaction will proceed rapidly and the operation will be highly dangerous. Therefore, granular metallic magnesium powder with a particle size of 100 μm to 1000 μm in the mesh pass of the sieve is preferred, and particularly granular metallic magnesium powder with a particle size of 200 μm to 500 μm is preferred. However, even if not all of metallic magnesium powder 18 is within the above particle size range, it is sufficient if 80 mass% or more, particularly 90 mass% or more, is within the above range.

[0057] The amount of metallic magnesium powder 18 added to zirconium oxide powder 17 coated with the aluminum oxide-based composition affects the reducing power of metallic magnesium. If the amount of metallic magnesium is too small, it will be difficult to obtain the desired zirconium nitride powder due to insufficient reduction. If it is too large, the reaction temperature will rise rapidly due to excessive metallic magnesium, which may cause grain growth of the powder and is uneconomical. Metallic magnesium powder 18 is added to and mixed with the coated zirconium oxide powder 17 such that the ratio of metallic magnesium to zirconium oxide is 2.0 to 6.0 times the molar amount depending on the particle size of metallic magnesium powder 18. If it is less than 2.0 times the molar amount, the reducing power of metallic magnesium is insufficient. If it exceeds 6.0 times the molar amount, the reaction temperature will rise rapidly due to excessive metallic magnesium, which may cause grain growth of the powder and is uneconomical. A ratio of 3.0 to 5.0 times the molar amount is preferred.

[0058] [Magnesium Oxide Powder] The magnesium oxide powder 19 is for preventing sintering of zirconium nitride produced by the reduction reaction of zirconium oxide with metallic magnesium. Its usage amount varies depending on the particle size of magnesium oxide, but it is preferably 0.3 to 5.0 times moles relative to 1 mole of zirconium oxide powder. As long as the magnesium oxide powder 19 is in an amount capable of preventing sintering of zirconium nitride, if used in excess, the amount of acidic solution required during pickling after the reaction increases. Therefore, it is preferably used within the above range.

[0059] [Firing of a mixture of ZrO2 powder coated with an aluminum oxide-based composition, metallic Mg powder, and MgO powder] The zirconium oxide powder 17 coated with the aluminum oxide-based composition of the present embodiment, the metallic magnesium powder 18, and the magnesium oxide powder 19 are placed in a reaction vessel (not shown), and these mixtures 20 are fired. The temperature during the reduction reaction with metallic magnesium for reducing the zirconium oxide powder 17 coated with the aluminum oxide-based composition to produce zirconium nitride powder, that is, the firing temperature, is 700°C to 1100°C, preferably 900°C to 1100°C. 650°C is the melting temperature of metallic magnesium. If the temperature is lower than that, the reduction reaction of zirconium oxide does not occur sufficiently. Also, even if the temperature is increased above 1100°C, the effect does not increase, resulting in waste of thermal energy and progress of particle sintering, which is not preferable. Also, the reduction reaction time, that is, the firing time, is 30 minutes to 180 minutes, preferably 60 minutes to 120 minutes for the same reason as the reduction reaction temperature. During this reduction reaction, that is, during firing, the atmospheric gas is a nitrogen gas atmosphere to prevent oxidation of the reduction product. To promote the above reduction reaction, a mixed gas of nitrogen gas and hydrogen gas, or a mixed gas of nitrogen gas and ammonia gas may be used. The above mixture 20 is fired to obtain a fired product 21.

[0060] [Treatment of the Fired Product] The fired product 21 obtained by firing the above mixture was taken out of the reaction vessel, and finally cooled to room temperature, and then washed with an acid solution 22 such as an aqueous hydrochloric acid solution to prevent the oxidation of metallic magnesium and the sintering of the product. Magnesium oxide (MgO) initially contained for this purpose and magnesium nitride (Mg3N2) generated by firing are removed. Regarding this acid washing, it is preferably carried out at a pH of 0.5 or more, particularly 1.0 or more, and a temperature of 90°C or less. This is because if the acidity is too strong or the temperature is too high, zirconium may elute. After the acid washing, the pH is adjusted to 5 to 6 with aqueous ammonia or the like, and then the solid content is separated by filtration or centrifugation. After drying the solid content, it is pulverized to obtain the zirconium nitride powder 23 containing the aluminum oxide-based composition of the present embodiment. The zirconium nitride powder 23 containing the aluminum oxide-based composition may contain impurities that can be contained in the process, which are derived from the raw materials used or the material of the reaction vessel made of stainless steel. Examples of the 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. Even when these impurities are contained in trace amounts in the zirconium nitride powder 23 containing the aluminum oxide-based composition, they do not particularly affect its optical properties, electrical insulation, and property changes in a constant temperature and humidity environment.

[0061] 〔Properties of Zirconium Nitride Powder Containing Aluminum Oxide-Based Composition〕 The zirconium nitride powder containing the aluminum oxide-based composition obtained in this embodiment has an aluminum oxide-based composition derived from a water-soluble aluminum compound partially adhering to its surface, and when the total amount of the powder is 100% by mass, aluminum is contained in a proportion exceeding 1% by mass and not exceeding 15% by mass. If this proportion is 1% by mass or less, the aluminum content of the zirconium nitride powder is too low, and the moisture resistance of the powder cannot be improved. Also, the effects of improving crystallinity and making the particles finer and more uniform due to the thermite reduction reaction of aluminum are not manifested, and the light transmittance at a wavelength of 370 nm decreases. If this proportion exceeds 15% by mass, the moisture resistance of the powder can be improved, but since aluminum oxide has a high dielectric constant, the light shielding property in the near-infrared region at a wavelength of 1000 nm decreases. The preferred content ratio is 1.1% by mass to 15% by mass, and the more preferred content ratio is 1.5% by mass to 14% by mass.

[0062] As shown in FIG. 2, it can be confirmed that in this zirconium nitride powder 23, the aluminum oxide-based composition is partially adhering to the surface of the powder 23a. However, at this stage, it cannot be confirmed whether the aluminum oxide-based composition 23b is contained inside the powder 23a. Also, the surface of the zirconium nitride powder 23a to which the aluminum oxide-based composition is not adhering is mostly exposed zirconium nitride, but may also be a thin oxide layer of an aluminum compound.

[0063] The presence or absence of the adhesion of the aluminum oxide-based composition on the surface of the powder is confirmed using a scanning transmission electron microscope (STEM) and energy-dispersive X-ray spectroscopy (EDS). Specifically, the confirmation of the presence or absence is performed by setting the magnification to a value where 1 to 5 particles can be confirmed, within the range of 10,000 times to 200,000 times, using STEM (Titan G2 ChemiSTEM manufactured by Thermo Fisher Scientific), and observing the particle appearance under the condition of an acceleration voltage of 200 kV. Furthermore, the confirmation of the presence or absence is performed by performing elemental mapping for aluminum element, zirconium element, oxygen element, and nitrogen element using EDS (Velox manufactured by Thermo Fisher Scientific) in the same field of view, and discriminating between the aluminum oxide-based composition and zirconium nitride. Briefly, it is also possible to discriminate between the aluminum oxide-based composition and zirconium nitride from the contrast difference between the aluminum element and zirconium element in the high-angle annular dark field (HAADF) image when observing the particle appearance. Here, examples of the aluminum oxide-based composition include alumina (including Al2O3, α-alumina, θ-alumina, γ-alumina), aluminum hydroxide (Al(OH)3), and the like.

[0064] The aluminum content is measured using an inductively coupled plasma optical emission spectrometer (ICP optical emission spectrometer ICPS-7510 manufactured by Shimadzu Corporation).

[0065] Also, the aluminum oxide-based composition-containing zirconium nitride powder has a BET specific surface area of 30 m 2 / g to 90 m 2 / g. If the specific surface area of this zirconium nitride powder is less than 30 m 2 / g, there is a problem that the pigment precipitates during long-term storage when used as a black resist. If it exceeds 90 m 2 / g, there is a problem that the visible light shielding performance is insufficient when forming a patterning film as a black pigment. 30 m 2 / g to 70 m 2 / g is preferred. The average particle diameter regarded as spherical can be calculated from the above specific surface area by the following formula (6). The average particle diameter of the zirconium nitride powder of the present embodiment calculated from this BET specific surface area is 10 nm to 40 nm. In formula (6), L is the average particle diameter (μm), ρ is the density of the powder (g / cm 3 ), and S is the specific surface area of the powder (m 2 / g). L = 6 / (ρ × S) (6)

[0066] In the zirconium nitride powder containing the aluminum oxide-based composition of the present embodiment, an aluminum oxide-based composition derived from a water-soluble aluminum compound is partially attached to the surface of the zirconium nitride particles and exists. As in Patent Document 2, when the surface of the zirconium nitride powder is completely covered with alumina, since alumina has a high dielectric constant, light on the long wavelength side of 1000 nm is transmitted. On the other hand, when alumina is partially attached to the powder surface as in the zirconium nitride powder containing the aluminum oxide-based composition of the present embodiment, while the moisture resistance is improved, the shielding property of zirconium nitride is maintained, so it has high light-shielding property. Further, as described above, since the aluminum oxide-based composition covering zirconium oxide acts as an auxiliary agent for the thermite reduction reaction, the crystallinity of the zirconium nitride powder containing the aluminum oxide-based composition of the present embodiment is not decreased and is kept high. As a result, the light transmittance in the ultraviolet region with a wavelength of 370 nm is improved, and the light transmittance in the near-infrared region does not increase (the light-shielding property is improved).

[0067] In the zirconium nitride powder containing an aluminum oxide-based composition of the present embodiment, further, in the dispersion transmission spectrum with a powder concentration of 50 ppm, the light transmittance X at 370 nm is preferably 20% or more, and the light transmittance Y at 1000 nm is preferably 35% or less. When the light transmittance X is less than 20%, when forming a patterning film as a black pigment, the bottom of the photoresist film is not exposed, and an undercut of the patterning film is likely to occur. Further, when the light transmittance Y exceeds 35%, the light shielding property in the near-infrared region of the formed patterning film is likely to be insufficient. A more preferable light transmittance X is 25% or more, and an even more preferable light transmittance Y is 30% or less. Considering the antinomic characteristics of the light transmittance X and the light transmittance Y, in the zirconium nitride powder containing an aluminum oxide-based composition of the present embodiment, the light transmittance X at 370 nm with respect to the light transmittance Y at 1000 nm (X / Y) is preferably 1.1 or more, and more preferably 1.2 or more. That is, when X / Y is 1.1 or more, there is an effect of ultraviolet light transmission, and it is more likely that an undercut of the patterning film does not occur.

[0068] In addition, for the zirconium nitride powder containing an aluminum oxide-based composition of the final product that satisfies the above optical characteristics, when measuring the optical characteristics, it is essential to keep the particles from aggregating and in a sufficiently dispersed state. Sufficient dispersion can be achieved, for example, by using a polymer-based dispersant having a functional group such as phosphoric acid, carboxylic acid, or amine, and performing a dispersion treatment for a predetermined time using grinding media such as zirconia beads. As an index of the degree of dispersion, in a particle size distribution system of the dynamic light scattering method (for example, UPA manufactured by Microtrac or SZ-100 manufactured by Horiba), it can be mentioned that secondary aggregates exceeding 200 nm are not confirmed.

[0069] 〔Preparation of black dispersion〕 A black dispersion is prepared by dispersing the zirconium nitride powder containing an aluminum oxide-based composition of the final product in a monomer compound such as a solvent, an acrylic monomer, or an epoxy monomer.

[0070] An acrylic monomer is a monomer having a (meth)acryloyl group. The (meth)acryloyl group includes an acryloyl group and a methacryloyl group. The acrylic monomer may be a monofunctional acrylic monomer having one (meth)acrylic group in one molecule, or may be a polyfunctional acrylic monomer having two or more (meth)acrylic groups in one molecule.

[0071] Examples of the monofunctional (meth)acrylic monomer 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, isodecyl (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, isobornyl (meth)acrylate, and the like.

[0072] Examples of the difunctional (meth)acrylic monomer 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, neopentyl triethylene glycol di(meth)acrylate, and the like.

[0073] Examples of the polyfunctional (meth)acrylic monomer include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, and the like.

[0074] The epoxy monomer has an epoxy group. The epoxy monomer may be a monofunctional epoxy monomer having one epoxy group in one molecule, or a polyfunctional epoxy monomer having two or more epoxy groups in one molecule. Examples of the epoxy monomer include glycidyl ether and alicyclic epoxy.

[0075] By adding this black dispersion liquid, which is the monomer dispersion, into the polymer, a resin composition containing the dispersed zirconium nitride powder is produced, and a resin molded body is formed from this resin composition. Further, the black dispersion liquid, which is the monomer dispersion, may further contain metal oxide powder and can further contain a plasticizer. The plasticizer is not particularly limited, and examples thereof 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 glycerin monooleate, aliphatic dibasic acid ester plasticizers such as dibutyl adipate and di-2-ethylhexyl sebacate; dihydric alcohol ester plasticizers such as diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate; and conventionally known plasticizers such as methyl acetylricinoleate and tributyl acetylcitrate.

[0076] Furthermore, another monomer can be added to the black dispersion which is a monomer dispersion. There is no particular limitation on the other monomer, and examples thereof include (meth)acrylic monomers such as (meth)acrylic acid and (meth)acrylic acid esters, styrene monomers such as styrene, vinyltoluene, and divinylbenzene, vinyl monomers such as vinyl chloride and vinyl acetate, urethane monomers such as urethane acrylate, and the above-mentioned various polyols, and conventionally known monomers can be mentioned. In addition, the viscosity of the monomer dispersion is preferably set within the range of 10 mPa·s to 1000 mPa·s in consideration of the dispersibility of the zirconium nitride powder. The dispersion of the monomer can be carried out in the same manner as the dispersion in the solvent described below using a mill method using grinding media. Also, although not an essential component, it is also possible to use a polymer dispersant to improve the dispersibility. It is effective that the polymer dispersant has a molecular weight of several thousand to several tens of thousands.

[0077] In addition, examples of the functional groups of the polymer dispersant adsorbed on the pigment include secondary amines, tertiary amines, carboxylic acids, phosphoric acids, phosphate esters, etc., and particularly tertiary amines and carboxylic acids are effective. Adding a small amount of a silane coupling agent instead of the polymer dispersant is also effective for improving the dispersibility. On the other hand, after performing planetary stirring, it is also possible to obtain a black dispersion by passing it through a three-roll mill several times.

[0078] Regarding the black dispersion dispersed in the solvent, adding a polymer dispersant is also effective in the same manner as the black dispersion in which the monomer compound is dispersed. The polymer dispersant is effective when the molecular weight is several thousand to several tens of thousands in the same manner as the black dispersion in which the monomer compound is dispersed, and as the functional groups of the polymer dispersant, tertiary amines, carboxylic acids, and phosphoric acids are effective. Examples of the solvent include isopropanol (IPA), butyl acetate (BA), methyl ethyl ketone (MEK), etc.

[0079] 〔Preparation of Black Photosensitive Composition〕 A black composition is prepared in which zirconium nitride powder containing an aluminum oxide-based composition of a final product is dispersed in a dispersion medium as a black pigment, and a resin is further mixed. Examples of the dispersion medium include propylene glycol monomethyl ether acetate (PGM-Ac), methyl ethyl ketone (MEK), and butyl acetate (BA). Examples of the resin include a photosensitive acrylic resin and an epoxy resin.

[0080] 〔Method for forming a patterning film using zirconium nitride powder containing an aluminum oxide-based composition as a black pigment〕 A method for forming a patterning film typified by a black matrix using the zirconium nitride powder containing the aluminum oxide-based composition as a black pigment will be described. First, the zirconium nitride powder containing the aluminum oxide-based composition is dispersed in a solvent to prepare a black dispersion. It is preferable to use an amine-based dispersant. Examples of the solvent include propylene glycol monomethyl ether acetate (PGM-Ac), diethyl ketone, and butyl acetate. A photosensitive acrylic resin is added to and mixed with this dispersion in a ratio such that the mass ratio of black pigment:resin is (10:90) to (80:20) to prepare a black photosensitive composition. Next, after applying this black photosensitive composition onto a substrate, pre-baking is performed to evaporate the solvent and form a photoresist film. Next, after exposing this photoresist film to a predetermined pattern shape through a photomask, development is performed using an alkaline developer to dissolve and remove the unexposed portion of the photoresist film, and then preferably post-baking is performed to form a predetermined black patterning film.

[0081] Examples of the substrate include glass, silicon, polyethylene terephthalate, polycarbonate, polyester, aromatic polyamide, polyamideimide, polyimide, and the like. The substrate can also be appropriately pretreated, if desired, with chemical treatment using a silane coupling agent or the like, plasma treatment, ion plating, sputtering, vapor phase reaction method, vacuum evaporation, or the like. When applying the black photosensitive composition to the substrate, an appropriate coating method such as spin coating, casting coating, roll coating, or the like can be employed. The coating thickness, as the film thickness after drying, is usually 0.1 μm to 10 μm, preferably 0.2 μm to 7.0 μm, and more preferably 0.5 μm to 6.0 μm. As the electromagnetic wave used for forming the patterning film, in this embodiment, an electromagnetic wave having a wavelength in the range of 250 nm to 370 nm is preferred. The integrated light amount of the electromagnetic wave is preferably 10 J / m 2 ~10,000 J / m 2 is used.

[0082] Examples of the alkaline developer include aqueous solutions of sodium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo-[4.3.0]-5-nonene, and the like. An appropriate amount of a water-soluble organic solvent such as methanol or ethanol, a surfactant, or the like can also be added to the alkaline developer. After alkaline development, it is usually washed with water. As the development treatment method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid reservoir) development method, or the like can be applied, and the development conditions are preferably 5 seconds to 300 seconds at room temperature. The patterning film formed in this way is suitably used for high-definition liquid crystals, black matrices for organic ELs, light-shielding materials for image sensors, light-shielding materials for optical members, light-shielding filters, IR cut filters, and the like. In addition, this black patterning film is used as an element constituting the black film. Specifically, a black film can be obtained by providing a support film and this black patterning film on the support film.

Examples

[0083] Next, examples of the present invention will be described in detail together with comparative examples.

[0084] <Example 1> 5 g of monoclinic zirconium dioxide powder with a BET specific surface area of 30 m 2 / g was added to 500 g of water and mixed to prepare a zirconium oxide slurry. As an aluminum source, aluminum chloride hexahydrate was dissolved in water, and this solution was added to and mixed with the zirconium oxide slurry to obtain a mixed solution. The addition amount of aluminum chloride hexahydrate was 12% by mass when the zirconium oxide was 100% by mass in terms of Al2O3. The mixed solution was maintained at 70°C. Ammonia water was dropped into the obtained mixed solution to adjust the pH of the mixed solution to 7. After maintaining the mixed solution at 70°C for 30 minutes, decantation was performed, and the precipitate was filtered. The solid content was dried at a temperature of 120°C for 12 hours using a hot air dryer. When this dried powder was observed with a scanning transmission electron microscope (STEM), it was found to be zirconium oxide powder partially covered with an aluminum oxide-based composition on the powder surface. When analyzed with the above-described electron beam diffraction apparatus, the aluminum oxide-based composition was amorphous aluminum oxide.

[0085] Next, 5.5 g of zirconium oxide powder coated with an aluminum oxide-based composition (5 g as zirconium oxide), 4.9 g of metallic magnesium powder (5 moles relative to zirconium oxide), and 4.9 g of magnesium oxide powder (3 moles relative to zirconium oxide) were mixed. The number of moles in parentheses is the ratio relative to 1 mole of zirconium oxide. This mixture was placed in a reaction vessel and fired at 900 °C for 60 minutes under a nitrogen gas atmosphere. The fired product was dispersed in 0.1 liter of water, and 10% hydrochloric acid was gradually added while maintaining the pH at 1 or higher and the temperature at 90 °C or lower. After washing, the pH was adjusted to 7 - 8 with 25% aqueous ammonia and filtered. The filtered solid content was redispersed in 0.4 liter of water, and again, acid washing and pH adjustment with aqueous ammonia were performed in the same manner as above, followed by filtration. After repeating the acid washing - pH adjustment with aqueous ammonia twice in this way, the filtrate was dispersed in ion-exchanged water at a solid content conversion of 5 g / liter, heated and stirred at 60 °C, and the pH was adjusted to 7. After filtration with a suction filtration device, it was further washed with an equal amount of ion-exchanged water and dried with a hot air dryer set at 120 °C to obtain the final product powder. The production conditions of Example 1 are shown in Table 1 below. Also, a scanning transmission electron microscope (STEM) photograph of the powder of Example 1 is shown in Figure 2. Figure 2 shows zirconium nitride powder 23a containing an aluminum oxide-based composition in which the surface of the black zirconium nitride powder 23a is partially adhered with a gray aluminum oxide-based composition 23b.

[0086]

Table 1

[0087] <Examples 2 - 7 and Comparative Examples 2, 3> In the production of the powders of the final products of Examples 2 to 7 and Comparative Examples 2 and 3, the BET specific surface area of the starting zirconium oxide (ZrO2) powder was made the same as or changed from that of Example 1, the aluminum source was made the same as or changed from that of Example 1, its addition amount was made the same as or changed from that of Example 1, and the neutralizing agent was made the same as or changed from that of Example 1. Also, the addition ratios of metallic magnesium (metal Mg) powder and magnesium oxide (MgO) powder to the zirconium oxide (ZrO2) powder, the atmosphere, temperature, and time during firing were each made the same as or changed from those of Example 1 to obtain the powders of the final products of Examples 2 to 7 and Comparative Examples 2 and 3. These details are shown in Table 1 above.

[0088] <Comparative Example 1> In Comparative Example 1, the powder of the final product was obtained by the method shown in Example 1 according to Claim 2 of Patent Document 2. Specifically, to 7.4 g of monoclinic zirconium dioxide powder with a BET specific surface area of 30 m 2 / g, 7.3 g of metallic magnesium powder with an average particle diameter of 150 μm and 3.0 g of magnesium nitride powder with an average particle diameter of 200 nm were added and uniformly mixed using a reactor equipped with a graphite boat inside a quartz glass tube. At this time, the addition amount of metallic magnesium was 5.0 times the molar amount of zirconium dioxide, and the addition amount of magnesium nitride was 0.5 times the molar amount of zirconium dioxide. This mixture was fired at a temperature of 700 °C for 60 minutes in an atmosphere of nitrogen gas to obtain a fired product. This fired product was dispersed in 0.1 liter of water, 17.5% hydrochloric acid was gradually added, and it was washed while maintaining the pH at 1 or more and the temperature at 90 °C or less. Then, it was adjusted to pH 7 - 8 with 2.5% aqueous ammonia and filtered. The filtered solid content was redispersed in 0.4 liter of water, and again, after acid washing and pH adjustment with aqueous ammonia in the same manner as above, it was filtered. After repeating the acid washing - pH adjustment with aqueous ammonia twice in this way, the filtrate was dispersed in ion-exchanged water at a solid content conversion of 5 g / liter, heated and stirred at 60 °C and adjusted to pH 7, then filtered using a suction filtration device, further washed with an equal amount of ion-exchanged water, and dried using a hot air dryer set at a temperature of 120 °C to obtain zirconium nitride powder.

[0089] The above zirconium nitride was pulverized in water using a bead mill (using zirconia beads with a diameter of 0.3 mm), thereby obtaining zirconium nitride powder with an average particle diameter of 30 nm. To this pulverized zirconium nitride slurry (zirconium nitride powder (black pigment) concentration: 10%), a 5% aluminum hydroxide solution (a solution obtained by dissolving aluminum hydroxide in caustic soda) was added such that the amount of Al2O3 became 5% with respect to 100% by mass of zirconium nitride. The pH of the slurry at this time was 10. Next, 17.5% hydrochloric acid was dropped into the above slurry until the pH reached 5. As a result, aluminum hydroxide was deposited on the surface of the zirconium nitride. The slurry was decanted several times for washing and then filtered to recover the cake (debris deposited on the surface of the filter medium). The obtained cake was baked by holding it at a temperature of 300 °C for 1 hour in a nitrogen atmosphere, thereby obtaining the powder of the final product coated with aluminum oxide.

[0090] <Comparative Example 4> In Comparative Example 4, the powder of the final product was obtained by the method of Example 1 according to Claim 3 of Patent Document 1. Monoclinic zirconium dioxide powder with a BET specific surface area of 30 m 2 / g without an aluminum source was used as the starting material. Specifically, the BET method was 30 m 2To 7.4 g of monoclinic zirconium dioxide powder per g, 7.3 g of magnesium metal powder with an average particle size of 150 μm and 3.0 g of magnesium nitride powder with an average particle size of 200 nm were added, and they were uniformly mixed using a reactor equipped with a graphite boat in a quartz glass tube. At this time, the addition amount of magnesium metal was 5.0 times the molar amount of zirconium dioxide, and the addition amount of magnesium nitride was 0.5 times the molar amount of zirconium dioxide. This mixture was fired at a temperature of 700 °C for 60 minutes in an atmosphere of nitrogen gas to obtain a fired product. This fired product was dispersed in 0.1 liter of water, 10% hydrochloric acid was gradually added, and it was washed while maintaining the pH at 1 or more and the temperature at 90 °C or less. Then, it was adjusted to pH 7 - 8 with 25% aqueous ammonia and filtered. The filtered solid content was redispersed in water to 0.4 liter, and again, after pickling and pH adjustment with aqueous ammonia in the same manner as above, it was filtered. After repeating the pickling - pH adjustment with aqueous ammonia twice in this way, the filtrate was dispersed in ion - exchanged water at 5 g / liter in terms of solid content, heated and stirred at 60 °C and adjusted to pH 7, then filtered with a suction filtration device, further washed with an equal amount of ion - exchanged water, and dried with a hot air dryer set at a temperature of 120 °C to obtain the powder of the final product.

[0091] The manufacturing conditions of Comparative Example 1 and Comparative Example 4 are shown in Table 1 above.

[0092] <Comparative Test> The powders of the final products of Examples 1 - 7 and Comparative Examples 1 - 4 were used as samples. From these samples, the presence or absence of an aluminum oxide - based composition was confirmed and the type of powder was determined based on this, and the content ratio of aluminum was measured. This confirmation and measurement were carried out by the methods described above. Next, for these samples, (1) the BET specific surface area was measured, (2) readings were taken from the spectral curves of the light transmittance X at 370 nm and the light transmittance Y at 1000 nm, and the calculation of X / Y was performed. Further, (3) the moisture resistance was measured. The results are shown in Table 2 below. In Table 2, 'aluminum oxide' is described as 'Al oxide'.

[0093] (1) BET specific surface area: For all samples, the BET one-point method by nitrogen adsorption was measured using a specific surface area measuring device (manufactured by Shibata Chemical Co., Ltd., SA-1100).

[0094] (2) Spectral curves in a dispersion with a powder concentration of 50 ppm: For each sample of Examples 1 to 7 and Comparative Examples 1 to 4, these samples were separately placed in a circulating horizontal bead mill (media: zirconia), an amine-based dispersant was added, and dispersion treatment was performed in a propylene glycol monomethyl ether acetate (PGM-Ac) solvent. The obtained 11 types of dispersions were diluted 100,000 times to adjust the powder concentration to 50 ppm. The light transmittance of each sample in this diluted dispersion was measured in the wavelength range from 240 nm to 1300 nm using Hitachi High-Tech Fielding ((stock) (UH-4150)) to obtain spectral curves. The light transmittance X at a wavelength of 370 nm near the i-line (365 nm) and the light transmittance Y at a wavelength of 1000 nm were read from the spectral curves. Fig. 1 shows the three spectral curves of Example 1 and Comparative Examples 1 and 2.

[0095] X / Y was calculated from the light transmittance X and the light transmittance Y read from the spectral curves of each sample of Examples 1 to 7 and Comparative Examples 1 to 4.

[0096] (3) Moisture resistance: To confirm the effect of aluminum content, the moisture resistance of all samples was examined. For each powder of Examples 1 to 7 and Comparative Examples 1 to 4, an amine-based dispersant was added, and dispersion treatment was performed in a propylene glycol monomethyl ether acetate (PGM-Ac) solvent to prepare a dispersion. Acrylic resin was added to this dispersion at a mass ratio of black pigment: resin = 5:5 and mixed to prepare a black composition. This black composition was spin-coated on a glass substrate and held at a temperature of 250 °C for 30 minutes to obtain a dried coating film with a thickness of 1 μm. The volume resistivity of these coating films was measured respectively. A sample of the prepared coating film was placed in a thermo-hygrostat set at a temperature of 60 °C and a humidity of 90% for 100 hours to conduct a high-temperature and high-humidity test. The volume resistivity of each coating film before and after the test was measured at a voltage of 1000 V using a Hirester (model number: MCP-HT800) manufactured by Mitsubishi Chemical Analytech Co., Ltd. The moisture resistance of the sample was determined to be "good" when the ratio R in the following formula (7), which is obtained from the difference in the surface resistivity of each film before and after the test, was less than 50%. When this difference was 50% or more, it was considered to have no moisture resistance and was rated as "poor". R = [(Resistivity after change - Resistivity before change) / Resistivity before change] × 100 (7)

[0097]

Table 2

[0098] <Evaluation> As is clear from Table 2, in Comparative Example 1, since aluminum hydroxide solution was added to zirconium nitride slurry to produce zirconium nitride powder, when the powder of this final product was observed by STEM, it was confirmed that the surface of the zirconium nitride powder was coated with alumina. Although the moisture resistance of this powder was good, since the powder was completely coated with alumina, the light-shielding property of zirconium nitride was inhibited by alumina, and the value of X / Y became 0.95, which was lower than 1.1.

[0099] In Comparative Example 2, the addition amount of aluminum chloride hexahydrate, which is an aluminum source, was too small at 0.6% by mass, and the aluminum content ratio in the powder of the final product was too small at 0.3% by mass. Therefore, when the powder of this final product was observed by STEM, it was confirmed that an aluminum oxide-based composition was slightly attached to the surface of this zirconium nitride powder. In this powder, the BET specific surface area was 29 m 2 / g was small (the average particle size was large). That is, coarsening of the particles in the thermite reduction reaction by the aluminum oxide-based composition could not be suppressed. For this reason, the transmittance X at 370 nm was 19.3%, which was less than 20%, the value of X / Y was 0.95, which was less than 1.1, and the transmittance in the near-ultraviolet region was low. Also, the moisture resistance was poor because the content ratio of aluminum was low.

[0100] In Comparative Example 3, the addition amount of aluminum chloride hexahydrate, which is an aluminum source, was too much at 38.0% by mass, and the content ratio of aluminum in the powder of the final product was too much at 17.0% by mass. When the powder of this final product was observed by STEM, it was confirmed that the surface of this zirconium nitride powder was almost covered with an aluminum oxide-based composition. For this reason, in this powder, the moisture resistance was good, but since the excessive alumina compound had light transmittance in the near-infrared region, the transmittance Y at 1000 nm was 40%, the value of X / Y was 1.05, and it was less than 1.1. Also, since the BET specific surface area was too large at 100 m 2 / g, the dispersion of the powder of the final product was insufficient and the shielding property in the visible light region also decreased.

[0101] In Comparative Example 4, when the powder of the final product was observed by STEM, it was confirmed that no aluminum oxide-based composition was present on the surface of this zirconium nitride powder. Since the surface of this powder was not coated with alumina and did not contain aluminum, the moisture resistance was poor. Also, the BET specific surface area of this powder was 26 m 2 / g and was small (the average particle size was large). That is, coarsening of the particles in the thermite reduction reaction by the aluminum oxide-based composition could not be suppressed. For this reason, the transmittance X at 370 nm was 19.0%, which was less than 20%, so the transmittance in the near-ultraviolet region was low, and the value of X / Y was 1.00.

[0102] In contrast, the final products of Examples 1 to 7 are zirconium nitride powders containing an aluminum oxide-based composition. When the powders of these final products were observed by STEM, it was confirmed that the surfaces of all the zirconium nitride powders were partially adhered with the aluminum oxide-based composition. When analyzed by an electron beam diffractometer, amorphous aluminum oxide was present in the powders of all the final products. Furthermore, the moisture resistance of the powders of all the final products was good, and the aluminum content was in the range exceeding 1% by mass and not exceeding 15% by mass. That is, the final products of Examples 1 to 7 satisfy the requirements of the first aspect of the present invention, and in addition to having high light-shielding performance for visible light, it was found that they are advantageous for patterning because they transmit ultraviolet light.

[0103] Particularly, the BET specific surface area is in the range of 30 m 2 / g to 90 m 2 / g, the light transmittance X at 370 nm is 20% or more, the light transmittance Y at 1000 nm is 35% or less, and the light transmittance X at 370 nm with respect to the light transmittance Y at 1000 nm (X / Y) is 1.1 or more. The final products of Examples 1 to 6 satisfy the requirements of the second aspect of the present invention, and it was found that they have even higher light-shielding performance for visible light and are even more advantageous for patterning because they transmit ultraviolet light.

Industrial Applicability

[0104] The zirconium nitride powder containing an aluminum oxide-based composition of the present invention can be used for high-definition liquid crystals, black matrices for organic ELs, light-shielding materials for image sensors, light-shielding materials for optical members, light-shielding filters, IR cut filters, black films, and the like.

Claims

1. An aluminum oxide-based composition derived from a water-soluble aluminum compound is partially adhered to the powder surface. When the total amount of the powder is 100% by mass, it contains aluminum at a ratio exceeding 1% by mass and not exceeding 15% by mass, and the specific surface area measured by the BET method is 30 m 2 / g to 90 m 2 / g. A zirconium nitride powder containing an aluminum oxide-based composition, characterized by this.

2. In the dispersion transmission spectrum with a powder concentration of 50 ppm, the light transmittance X at 370 nm is 20% or more, the light transmittance Y at 1000 nm is 35% or less, and the light transmittance X at 370 nm with respect to the light transmittance Y at 1000 nm (X / Y) is 1.1 or more. The zirconium nitride powder containing an aluminum oxide-based composition according to Claim 1.

3. Zirconium oxide powder coated with an aluminum oxide-based composition, 2.0 to 6.0 times the molar amount of metallic magnesium powder of the zirconium oxide, and 0.3 to 5.0 times the molar amount of magnesium oxide powder of the zirconium oxide are mixed to obtain a mixture, and then the mixture is fired at a temperature of 700 °C to 1100 °C for 30 minutes to 180 minutes in a nitrogen gas atmosphere by the thermite method to reduce the zirconium oxide powder, thereby producing the zirconium nitride powder containing an aluminum oxide-based composition according to Claim 1 or 2.

4. The method for producing zirconium nitride powder containing an aluminum oxide-based composition according to Claim 3, wherein the zirconium oxide powder coated with the aluminum oxide-based composition is obtained by adding and mixing a water-soluble aluminum compound to a zirconium oxide slurry in which zirconium oxide powder is dispersed in water to obtain a mixed solution, adding and mixing an alkali or an acid to the mixed solution, holding at a temperature of room temperature to 80 °C for at least 1 hour, and then subjecting the mixed solution to solid-liquid separation and drying.

5. The method for producing zirconium nitride powder containing an aluminum oxide-based composition according to Claim 4, wherein the water-soluble aluminum compound is an aluminum compound that becomes acidic when dissolved in water, and an alkali is added and mixed to the mixed solution.

6. The method for producing zirconium nitride powder containing an aluminum oxide-based composition according to Claim 4, wherein the water-soluble aluminum compound is an aluminum compound that becomes alkaline when dissolved in water, and an acid is added and mixed to the mixed solution.

7. A black dispersion in which the zirconium nitride powder containing an aluminum oxide-based composition according to Claim 1 or 2 is dispersed in a solvent or a monomer compound.

8. A black photosensitive composition containing the zirconium nitride powder containing an aluminum oxide-based composition according to Claim 1 or 2 as a black pigment.

9. A black patterning film obtained using the black photosensitive composition according to Claim 8.

10. The black matrix obtained by using the black patterning film according to claim 9.

11. The light-shielding material obtained by using the black patterning film according to claim 9.

12. The light-shielding filter obtained by using the black patterning film according to claim 9.

13. A black film comprising a support film and the black patterning film according to claim 9 on the support film.

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