JP7339080B2 - Zirconium nitride powder and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a zirconium nitride powder that has high ultraviolet transmittance and high blackness, and is suitably used as a black pigment having high insulating properties, and a method for producing the same.

Conventionally, the specific surface area measured by the BET method is 20 m ² /g to 90 m ² /g, and the X-ray diffraction profile has a peak of zirconium nitride, a peak of zirconium dioxide, and a peak of low order zirconium oxide. A zirconium nitride powder that does not contain a zirconium nitride is disclosed (see, for example, Patent Document 1 (claim 1, paragraph [0016])). This zirconium nitride powder has a light transmittance X at 370 nm of at least 18%, a light transmittance Y at 550 nm of 12% or less, and a light transmittance X at 370 nm in the dispersion liquid transmission spectrum with a powder concentration of 50 ppm. The light transmittance Y (X/Y) at 550 nm is 2.5 or more.

Since the zirconium ^nitride powder thus constituted has a specific surface area of 20 m ² /g or more, it has the effect of suppressing sedimentation when used as a resist. have the effect of In addition, in the X-ray diffraction profile, although it has a zirconium nitride peak, it does not have a zirconium dioxide peak, a low-order zirconium oxide peak, or a low-order zirconium oxynitride peak. The light transmittance X at 550 nm is at least 18%, the light transmittance Y at 550 nm is 12% or less, and X/Y is 2.5 or more. When X/Y is 2.5 or more, there is a feature that ultraviolet rays are transmitted more. As a result, when a black patterning film is formed using a black pigment, a high-resolution patterning film can be formed, and the formed patterning film has high light-shielding performance.

JP 2017-222559 A

In the zirconium nitride powder disclosed in Patent Document 1, high insulation can be obtained by dispersing coarse zirconium nitride powder in a dispersion medium and increasing dispersibility using a bead mill (media: zirconia) or the like. If the zirconium powder is directly kneaded into the high-viscosity resin paste, coarse zirconium nitride powder remains, resulting in insufficient dispersibility. For this reason, when zirconium nitride powder is used as a black pigment, the coloring power of the black paint is lowered, and the residual coarse zirconium nitride powder causes a decrease in the resistance value. Further, if the zirconium nitride coarse powder is forcibly pulverized with a dry pulverizer or the like, the powder diameter becomes small and an oxidation reaction occurs on the powder surface, which improves the insulation properties but lowers the blackness of the black paint. There was a problem.

A first object of the present invention is to provide a zirconium nitride powder having high blackness and high insulating properties, and a method for producing the same. A second object of the present invention is to provide a method for producing a zirconium nitride powder that can maintain a high degree of blackness by low-temperature wet media pulverization or by pulverization with a jet mill that generates less heat. A third object of the present invention is to provide a method for producing a zirconium nitride powder that can improve the insulating properties of a black film by firing in an inert gas atmosphere.

The first aspect of the present invention is the state of secondary particles in which primary particles are aggregated, does not contain low zirconium oxide and low zirconium oxynitride, and is compacted under a pressure of 5 MPa. Resistivity of 10 ⁷ Ω·cm or more and secondary particle size distribution D ₉₀ of 10 μm or less when ultrasonically dispersed for 5 minutes in a state diluted with water or alcohol having a carbon number of 2 to 5 is.

A second aspect of the present invention is a step of producing coarse zirconium nitride powder having a specific surface area of 20 m ² /g to 90 m ² /g by a thermite method or a plasma synthesis method; By performing low-temperature wet media pulverization at a dispersion medium temperature of , or jet mill pulverization at a gas pressure of 0.3 MPa or more, it is diluted with water or an alcohol having a carbon number of 2 to 5 for more than 5 minutes. a step of producing a zirconium nitride precursor powder having a particle size distribution D ₉₀ of 10 μm or less when sonically dispersed; firing the pulverized zirconium nitride precursor powder in an inert gas atmosphere at a temperature of 250° C. to 550° C.; a step of producing a zirconium nitride powder having a volume resistivity of 10 ⁷ Ω·cm or more in the state of a green compact compacted at a pressure of 5 MPa by firing under conditions of firing for 1 hour to 5 hours; A method for producing a zirconium nitride powder comprising:

A third aspect of the present invention is a monomer dispersion in which the zirconium nitride powder according to the first aspect is dispersed in an acrylic monomer or an epoxy monomer.

A fourth aspect of the present invention is a black composition in which the zirconium nitride powder according to the first aspect is dispersed as a black pigment in a dispersion medium and further mixed with a resin.

A fifth aspect of the present invention is a step of applying the monomer dispersion according to the third aspect to a substrate to form a coating film, and a step of thermosetting or ultraviolet curing the coating film to prepare a black film. and a method for producing a black film.

A sixth aspect of the present invention is a step of applying the black composition according to the fourth aspect to a substrate to form a coating film, and a step of thermally curing or ultraviolet curing the coating film to produce a black film. and a method for producing a black film.

The zirconium nitride powder of the first aspect of the present invention has a volume resistivity of 10 ⁷ Ω·cm or more in the state of a green compact compacted at a pressure of 5 MPa, so that a black thick film having a thickness of about 10 μm to 100 μm is formed. Insulation can be improved when the is produced. In addition, since the zirconium nitride powder has a particle size distribution _D90 of 10 μm or less when ultrasonically dispersed for 5 minutes in a state diluted with water or an alcohol having a carbon number in the range of 2 to 5, coarse zirconium nitride powder is present. good dispersions and liquid dispersions can be obtained. As a result, a black film produced from a dispersion or a dispersion liquid using the zirconium nitride powder has high light-shielding properties, that is, a high degree of blackness, and also has high insulating properties.

In the method for producing zirconium nitride powder according to the second aspect of the present invention, if the zirconium nitride coarse powder is subjected to low-temperature wet media pulverization at a dispersion medium temperature of 10° C. or less, the amount of heat generated is small, so the surface oxidation of zirconium nitride proceeds. First, a high degree of blackness can be maintained. Further, when the coarse zirconium nitride powder is pulverized by a jet mill under a gas pressure of 0.3 MPa or more, the coarse zirconium nitride powder does not remain and the insulation of the black film can be improved. Furthermore, the insulating properties of the black film can be improved by firing the pulverized zirconium nitride precursor powder in an inert gas atmosphere.

The monomer dispersion of the third aspect of the present invention is obtained by dispersing the zirconium nitride powder of the first aspect of the present invention in acrylic monomers or epoxy monomers. can maintain good dispersibility in the above monomers. As a result, the black film using the monomer dispersion can obtain high light-shielding properties, that is, high blackness, and has high insulating properties.

The black composition of the fourth aspect of the present invention is obtained by dispersing the zirconium nitride powder of the first aspect of the present invention as a black pigment in a dispersion medium and further mixing a resin, so that the zirconium nitride powder is uniformly dispersed in the dispersion medium. do. As a result, the black film using the black composition can obtain high light-shielding properties, that is, high blackness, and has high insulating properties.

In the method for producing a black film according to the fifth aspect of the present invention, the monomer dispersion is applied to a substrate to form a coating film, and then the coating film is thermally or ultraviolet cured to produce a black film. A black film can obtain a high light-shielding property, that is , a high degree of blackness, and has a high insulating property.

In the method for producing a black film according to the sixth aspect of the present invention, the black composition is applied to a substrate to form a coating film, and then the coating film is thermally or ultraviolet cured to produce a black film. A black film can obtain a high light-shielding property, that is , a high degree of blackness, and has a high insulating property.

Next, a mode for carrying out the present invention will be described. The zirconium nitride powder of the present embodiment has a volume resistivity of 10 ⁷ Ω·cm or more, preferably 10 ⁸ Ω·cm or more in the state of a compact compacted at a pressure of 5 MPa, and water or carbon number The particle size distribution D ₉₀ is 10 μm or less, preferably 8 μm or less when ultrasonically dispersed for 5 minutes in a state of being diluted with an alcohol within the range of 2 to 5. Here, the reason why the volume resistivity is limited to 10 ⁷ Ω·cm or more is that if the volume resistivity is less than 10 ⁷ Ω·cm, the insulating properties when a black thick film having a thickness of about 1 μm to 100 μm is produced using zirconium nitride powder. This is because the The reason why the particle size distribution D ₉₀ is limited to 10 μm or less is that if the particle size exceeds 10 μm, coarse zirconium nitride powder remains and a good dispersion or black film cannot be obtained.

The volume resistivity is measured by a four-terminal four-probe method using, for example, a low resistivity meter Loresta-GP (model: UV-3101PC) manufactured by Mitsubishi Chemical Corporation. This four-terminal four-probe method involves placing four needle-like electrodes on the surface of a sample (powder compact) in a straight line with a predetermined interval, and applying a constant electric current between the outer two needle-like electrodes. is allowed to flow, and the potential difference generated between the inner two needle-like electrodes is measured to determine the volume resistivity.

Zirconium nitride powder is in the state of secondary particles in which primary particles are aggregated, and the particle size distribution of the secondary particles of this powder is a volume-based particle size distribution measured by a laser diffraction scattering method. Here, the volume-based particle size distribution is measured by the laser diffraction scattering method as follows. First, 0.1 g of zirconium nitride powder (secondary particles) is put into 20 g of ion-exchanged water, and ultrasonic waves of 25 kHz are applied for 5 minutes to disperse the zirconium nitride powder in the ion-exchanged water. Next, an appropriate amount of the obtained zirconium nitride powder dispersion is dropped into an observation cell of a laser diffraction/scattering particle size distribution analyzer (manufactured by Horiba Ltd., trade name: LA-300), and the particle size distribution is measured according to the procedure of this apparatus. do. The particle size distribution measured by this laser diffraction scattering method is the particle size distribution of secondary particles in which the primary particles of the zirconium nitride powder are aggregated. An alcohol having a carbon number of 2 to 5 may be used instead of ion-exchanged water. Alcohols with 2 carbon atoms include ethanol, alcohols with 3 carbon atoms include 1-propanol, 2-propanol, etc., and alcohols with 4 carbon atoms include 1-butanol, 2-butanol, etc. Examples of alcohols having 5 carbon atoms include 1-pentanol and 2-pentanol. If the number of carbon atoms is 1 or less, the volatility is high and the measured value is unstable. If the number of carbon atoms is 6 or more, the affinity is insufficient and the measured value is unstable.

A method for producing the zirconium nitride powder thus configured will be described. First, zirconium nitride coarse powder is produced by the thermite method or plasma synthesis method. As used herein, the thermite method refers to a method of reducing zirconium oxide powder by reacting it with N ₂ gas (nitrogen gas) in the presence of metallic magnesium. In this embodiment, zirconium dioxide (ZrO ₂ ) powder or silica-coated zirconium dioxide (ZrO ₂ ) powder is used as the zirconium oxide powder. Also, magnesium nitride (Mg ₃ N ₂ ) powder is added to metallic magnesium powder. Using these powders as starting materials, they are fired under a specific atmosphere at a specific temperature and for a specific period of time to obtain coarse zirconium nitride powder having a specific surface area of 20 m ² /g to 90 m ² /g as measured by the BET method. Generate.

[Zirconium dioxide powder]
As the zirconium dioxide powder, for example, zirconium dioxide powders such as monoclinic zirconium dioxide, cubic zirconium dioxide, and yttrium-stabilized zirconium dioxide can be used, but the yield of zirconium nitride powder increases. From this point of view, monoclinic zirconium dioxide powder is preferred. In addition, each average primary particle size of the zirconium dioxide powder or the zirconium dioxide powder coated with silica and the average primary particle size of the magnesium oxide powder have a specific surface area measured by the BET method of 20 m ² /g to 90 m ² /g. In order to obtain the zirconium nitride coarse powder, the average primary particle size, which is sphere-converted from the measured value of the specific surface area, is preferably 500 nm or less. is preferably

[Zirconium dioxide powder coated with silica]
Zirconium dioxide powder coated with silica is obtained by mixing zirconium dioxide powder and a silicate sol-gel liquid to prepare a slurry, drying and pulverizing this slurry. The mixing ratio of zirconium dioxide and the silicate sol-gel liquid is preferably such that the mass ratio of zirconium dioxide:silica content of the silicate sol-gel liquid is (90.0 to 99.5):(10.0 to 0.5). If the silica content is less than the lower limit, the silica coverage on the zirconium dioxide surface is too low. There is

It is preferable to mix the zirconium dioxide powder in a dispersion medium such as water or alcohol, and then add and mix the mixed liquid with the silicate sol-gel liquid because the zirconium dioxide is uniformly mixed with the sol-gel liquid. The silicate sol-gel liquid is preferably a liquid in which a silicate such as methyl silicate or ethyl silicate is dissolved in a solvent such as water or alcohol. The mixing ratio of zirconium dioxide and the sol-gel liquid is determined so that the solid content concentration of the resulting slurry is 10% by mass to 50% by mass in terms of solid content. The obtained slurry is dried at a temperature of 60° C. to 350° C. for 1 minute to 360 minutes in air or in a vacuum atmosphere to obtain silica-coated zirconium dioxide powder.

By using silica-coated zirconium dioxide powder as a starting material, it is possible to suppress grain growth during firing, resulting in finer particles having a specific surface area of 20 m ² /g to 90 m ² /g as measured by the BET method. A zirconium nitride powder can be obtained. At this time, the zirconium nitride powder contains silicon oxide and/or silicon nitride in a proportion of 10.0 mass % or less, preferably 9.0 mass % or less. If it exceeds 10.0% by mass, there is a problem that the resulting zirconium nitride powder is used to form a patterned film, resulting in insufficient light shielding properties.

[Metallic magnesium powder]
If the particle size of the metallic magnesium powder is too small, the reaction will proceed rapidly and the operation will be dangerous. is preferred. However, even if all of metallic magnesium does not fall within the above particle size range, 80% by mass or more, particularly 90% by mass or more thereof may be within the above range.

The amount of metallic magnesium powder added to the zirconium dioxide powder affects the reducing power of zirconium dioxide together with the amount of ammonia gas and hydrogen gas in the atmospheric gas, which will be described later. If the amount of metallic magnesium is too small, it will be difficult to obtain the desired zirconium nitride powder due to insufficient reduction. become uneconomical. The metallic magnesium powder is added to and mixed with the zirconium dioxide powder so that the metallic magnesium powder is 2.0 to 6.0 times the molar ratio of the zirconium dioxide, depending on the size of the particle size. . If it is less than 2.0 times the molar amount, the reduction reaction of zirconium dioxide is insufficient, and if it exceeds 6.0 times the molar amount, the reaction temperature rises sharply due to excess metal magnesium, which may cause grain growth of the powder. become uneconomical.

[Magnesium nitride powder]
Magnesium nitride powder coats the surface of zirconium nitride during firing to reduce the reducing power of metallic magnesium, thereby preventing sintering and grain growth of zirconium nitride powder. The magnesium nitride powder is added to and mixed with zirconium dioxide so that the magnesium nitride is 0.3 to 3.0 times the molar ratio of zirconium dioxide, depending on the size of the particle size. If it is less than 0.3 mol, sintering of the zirconium nitride powder cannot be prevented, and if it exceeds 3.0 mol, there is a problem that the amount of acid solution required for acid washing after firing increases. It is preferably 0.4-fold molar to 2.0-fold molar. Magnesium nitride powder preferably has an average primary particle size of 1000 nm or less when converted to spheres from the measured specific surface area, and preferably has an average primary particle size of 10 nm or more and 500 nm or less from the viewpoint of easy handling of the powder. Since not only magnesium nitride but also magnesium oxide is effective in preventing sintering of zirconium nitride, it is possible to use a mixture of magnesium oxide and magnesium nitride.

[Reduction reaction with metallic magnesium powder]
The temperature during the reduction reaction with metallic magnesium for producing coarse zirconium nitride powder is 650°C to 900°C, preferably 700°C to 800°C. 650° C. is the melting temperature of metallic magnesium, and if the temperature is lower than 650° C., the reduction reaction of zirconium dioxide does not occur sufficiently. Also, even if the temperature is higher than 900° C., the effect does not increase, the heat energy is wasted, and the sintering of the powder proceeds, which is not preferable. The reduction reaction time is preferably 30 to 90 minutes, more preferably 30 to 60 minutes.

The reaction vessel in which the reduction reaction is carried out preferably has a lid so that the raw materials and products do not scatter during the reaction. This is because when the metal magnesium starts to melt, the reduction reaction proceeds rapidly, the temperature rises accordingly, the gas inside the container expands, and the contents inside the container scatter to the outside. Because it is possible.

[Atmospheric gas during reduction reaction with metallic magnesium powder]
The atmospheric gas is nitrogen gas alone, a mixed gas of nitrogen gas and hydrogen gas, or a mixed gas of nitrogen gas and ammonia gas. The reduction reaction is carried out in an airflow of the mixed gas. Nitrogen gas in the mixed gas has a role of preventing metal magnesium and reduction products from coming into contact with oxygen and oxidizing them, and reacting nitrogen with zirconium to produce zirconium nitride. Hydrogen gas or ammonia gas in the mixed gas has a role of reducing zirconium dioxide together with metallic magnesium. Hydrogen gas is preferably included in the mixed gas in an amount of 0% to 40% by volume, more preferably 10% to 30% by volume. Further, ammonia gas is preferably contained in the mixed gas in an amount of 0% to 50% by volume, more preferably 0% to 40% by volume. By using this reducing atmosphere gas, zirconium nitride powder containing no low zirconium oxide and low zirconium oxynitride can be finally produced. On the other hand, if the proportion of hydrogen gas or the proportion of ammonia gas is higher than this range, the reduction progresses, but the nitrogen source decreases, so that low order zirconium oxide or low order zirconium oxynitride is produced, which is not desirable. In addition, the reason why the ratio of ammonia gas is higher than that of hydrogen gas is considered to be that the gas nitriding ability of ammonia is higher than that of hydrogen.

On the other hand, the method of producing zirconium nitride coarse powder by plasma synthesis method is a method of introducing metal zirconium powder into a plasma nanoparticle production apparatus and obtaining zirconium nitride nanoparticles in an N ₂ gas atmosphere. Zirconium nitride synthesized by this method can be obtained with a specific surface area measured by the BET method of 20 m ² /g to 90 m ² /g, but the raw material, metallic zirconium, is highly combustible and dangerous. and a disadvantage of high cost. In addition, nanoparticles generated by the plasma synthesis method may be coarsened due to rapid surface oxidation, adhesion, aggregation, etc. during the cooling process and product removal process, and may become coarse powder. zirconium nitride coarse powder.

Next, this zirconium nitride coarse powder is subjected to low-temperature wet media pulverization at a dispersion medium temperature of 10 ° C. or less, or jet mill pulverization at a gas pressure of 0.3 MPa or more, to water or a carbon number range of 2 to 5 A zirconium nitride precursor powder having a particle size distribution D ₉₀ of 10 μm or less when ultrasonically dispersed for 5 minutes while being diluted with alcohol is prepared. The specific surface area of this zirconium nitride precursor powder measured by the BET method is 22 m ² /g to 120 m ² /g.

The low-temperature wet media pulverization method involves dispersing coarse zirconium nitride powder in a dispersion medium such as ion-exchanged water or an alcohol having 2 to 5 carbon atoms, and maintaining the temperature of the dispersion medium at 10 ° C. or less. It refers to a bead mill pulverization method using media such as zirconia, alumina, glass, and urethane resin of up to 500 μm. Here, the reason why the temperature of the dispersion medium is kept at 10° C. or less is that if the temperature exceeds 10° C., the zirconium nitride precursor powder is pulverized and the OD value of the black film, which will be described later, is lowered. In order to keep the temperature of the dispersion medium at 10° C. or lower, liquid nitrogen may be used as the dispersion medium, or dry ice beads may be used as the medium. In addition, when the zirconium nitride coarse powder is pulverized by the low-temperature wet media pulverization method, the zirconium nitride surface is not oxidized due to the small amount of heat generated, and a high degree of blackness can be maintained.

In addition, jet mill pulverization at a gas pressure of 0.3 MPa or more means that high-pressure air of 0.3 MPa or more injected from a nozzle, an inert gas such as nitrogen, or steam collides with the powder as an ultra-high-speed jet, It refers to pulverization to fine powder of several μm level by the impact of , and the jetted air or steam reaches around the speed of sound. A feature of the jet mill is that the temperature drops due to the adiabatic expansion of the injected gas, so pulverization at low temperatures is possible, and even reducing substances such as zirconium nitride in the present invention suppress oxidation. It is possible to Here, the reason why the gas pressure is limited to 0.3 MPa or more is that if the gas pressure is less than 0.3 MPa, coarse zirconium nitride powder remains. When the coarse zirconium nitride powder is pulverized by the jet mill pulverization method, the coarse zirconium nitride powder does not remain and the insulation of the black film can be improved.

Furthermore, by firing this pulverized zirconium nitride precursor powder in an inert gas atmosphere, a zirconium nitride powder having a volume resistivity of 10 ⁷ Ω·cm or more in the state of a compact compacted at a pressure of 5 MPa. to manufacture. Examples of inert gases include N ₂ gas, helium gas, argon gas, and the like. The firing temperature is preferably in the range of 250° C. to 550° C., and the firing time is preferably in the range of 1 hour to 5 hours. Here, the reason why the preferred firing temperature is limited to the range of 250° C. to 550° C. is that if the temperature is less than 250° C., the increase in the resistance value is insufficient, and if the temperature exceeds 550° C., fusion between the powders progresses and coarse powder is formed. This is because it will increase. The preferred firing time is limited to the range of 1 hour to 5 hours because the increase in resistance value is insufficient if the firing time is less than 1 hour, and the effect remains unchanged even if the firing time exceeds 5 hours, which is uneconomical. The insulating properties of the black film can be improved by firing the zirconium nitride precursor powder in an inert gas atmosphere. Although the detailed mechanism by which the insulating properties of the black film are improved by sintering in an inert gas atmosphere is unknown, it is possible that the coarse powder of zirconium nitride was eliminated and that the uniformity of the powder was improved, and that the contact points were reduced. It is presumed that this is due to the fact that the black film is reduced and an ultra-thin insulating layer is formed on the surface of the black film.

A monomer dispersion is prepared by dispersing the above zirconium nitride powder in an acrylic or epoxy monomer. This monomer dispersion is useful for applications such as resin compositions containing dispersed inorganic powder, resin moldings, and the like. In addition, the monomer dispersion may further contain a metal oxide powder and may further contain a plasticizer. The plasticizer is not particularly limited, but 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 glycerin monooleate; aliphatic dibasic ester plasticizers such as dibutyl adipate and di-2-ethylhexyl sebacate; diethylene glycol dibenzoate, triethylene Dihydric alcohol ester plasticizers such as glycol di-2-ethylbutyrate; and conventionally known plasticizers such as oxyester plasticizers such as methyl acetylricinoleate and acetyl tributyl citrate. Additionally, further monomers can be added to the monomer dispersion. Other monomers are not particularly limited, and examples include (meth) acrylic monomers such as (meth) acrylic acid and (meth) acrylic acid esters, styrene monomers such as styrene, vinyl toluene and divinyl benzene, vinyl chloride, Conventionally known monomers such as vinyl-based monomers such as vinyl acetate, urethane-based monomers such as urethane acrylate, and the various polyols described above can be used. The viscosity of the monomer dispersion is preferably set within the range of 10 Pa·s to 1000 mPa·s in consideration of the dispersibility of the zirconium nitride powder. Dispersion in the monomer can also be carried out by a mill method using grinding media, similar to dispersion in the solvent. Although not an essential component, it is also possible to use a polymer dispersant in order to further improve the dispersibility. It is effective for the polymer dispersant to have a molecular weight of thousands to tens of thousands, and functional groups that can be adsorbed by pigments include secondary amines, tertiary amines, carboxylic acids, phosphoric acids, and phosphoric acid esters. However, tertiary amines and carboxylic acids are particularly effective. Adding a small amount of a silane coupling agent instead of the polymer dispersant is also effective in improving the dispersibility. On the other hand, after applying planetary stirring, it is also possible to pass through a triple roll several times to obtain a monomer dispersion . On the other hand, a black composition is prepared by dispersing zirconium nitride powder as a black pigment in a dispersion medium and further mixing a resin. Examples of the dispersion medium include propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), butyl acetate (BA), and the like. Moreover, acrylic resin, epoxy resin, etc. are mentioned as said resin. For solvent-based dispersion, addition of a polymer dispersant is effective in the same manner as in monomer dispersion, and similar to monomer dispersion, it is effective to have a molecular weight of several thousand to several tens of thousands. Carboxylic acids are effective.

Next, a method for producing a black film using the above monomer dispersion will be described. First, after adding a photopolymerization initiator to a monomer dispersion, this monomer dispersion is applied to a substrate to form a coating film. Next, this coating film is thermally or ultraviolet cured to produce a black film. Examples of the substrate include glass, silicon, polycarbonate, polyester, aromatic polyamide, polyamideimide, and polyimide. If desired, the substrate may be subjected to appropriate pretreatments such as chemical treatment with a silane coupling agent, plasma treatment, ion plating, sputtering, vapor phase reaction method, vacuum deposition, and the like. When the monomer dispersion is applied to the substrate, an appropriate coating method such as spin coating, casting coating, roll coating, or the like can be employed.

In order to thermally cure the coating film, it is preferable to hold it at a temperature of 80° C. to 250° C. for 5 minutes to 60 minutes in the atmosphere. Here, the reason why the thermosetting temperature of the coating film is limited to within the range of 80° C. to 250° C. is that if the temperature is less than 80° C., the coating film is not sufficiently cured, and if it exceeds 250° C., the substrate softens. be. In addition, the reason why the thermal curing time of the coating film is limited to within the range of 5 minutes to 60 minutes is that the coating film does not fully cure if it is less than 5 minutes, and if it exceeds 60 minutes, it takes more time than necessary and is uneconomical. That's why. On the other hand, in order to cure the above coating film with ultraviolet rays, Irgacure 184 (manufactured by BASF), Irgacure 250 (manufactured by BASF), Irgacure 270 (manufactured by BASF), Irgacure 369 (manufactured by BASF), and Irgacure are added to the monomer dispersion in advance. 500 (manufactured by BASF), Irgacure 907 (manufactured by BASF), and ADEKA OPTOMER N-1919 (manufactured by ADEKA). Then, after coating the substrate with the monomer dispersion to which the photopolymerization initiator has been added, prebaking is performed to evaporate the solvent and form a photoresist film. Next, the photoresist film is exposed to light in a predetermined pattern through a photomask, developed with an alkaline developer to dissolve and remove the unexposed portions of the photoresist film, and then preferably post-baked. Thereby, a predetermined black film is formed.

The thickness of the black film after curing is preferably in the range of 0.1 μm to 100 μm. In particular, it is suitable for producing a thick black film with a film thickness of 10 μm to 100 μm. Also, the OD value (optical density value) of the black film is an optical density as an index representing the light shielding property (attenuation of transmittance) of the black film using the zirconium nitride powder. Specifically, the OD value is a logarithmic representation of the degree of light absorption when passing through a black film, and is defined by the following equation (1). In equation (1), I is the amount of transmitted light and I ₀ is the amount of incident light.
OD value = -log ₁₀ (I/I ₀ ) …………(1)
Furthermore, the OD value of the black film is preferably 2.0 or more in order to ensure high light shielding properties, and the volume resistivity of the black film is 1×10 ¹³ Ω· in order to ensure high insulation properties. cm or more is preferable.

A method for producing a black film using the black composition will be described. First, a black composition is applied to a substrate to form a coating film. Next, this coating film is thermally or ultraviolet cured to produce a black film. The method for producing a black film using this black composition is substantially the same as the method for producing a black film using the above-described monomer dispersion, and thus repeated description is omitted.

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

<Example 1>
First, zirconium nitride coarse powder was produced by the thermite method. Specifically, 7.4 g of monoclinic zirconium dioxide powder having an average primary particle size of 50 nm calculated from the specific surface area measured by the BET method, and 7.3 g of metallic magnesium powder having an average primary particle size of 150 μm. 3.0 g of magnesium nitride powder having an average primary particle size of 200 nm was added and uniformly mixed in a reaction apparatus having a graphite boat inside a quartz glass tube. At this time, the added amount of metallic magnesium was 5.0 times the molar amount of zirconium dioxide, and the added amount of magnesium nitride was 0.5 times the molar amount of zirconium dioxide. This mixture was baked at a temperature of 700° C. for 60 minutes in a nitrogen gas atmosphere to obtain a baked product. This baked product is dispersed in 1 liter of water, and 10% hydrochloric acid is gradually added to wash while maintaining the pH at 1 or more and the temperature at 100° C. or less. and filtered. The filtered solid matter was redispersed in water at 400 g/liter, washed with acid and pH adjusted with aqueous ammonia in the same manner as described above, and then filtered. After repeating acid washing and pH adjustment with aqueous ammonia twice in this way, the filtrate was dispersed in ion-exchanged water at a solid content conversion of 500 g/liter, heated and stirred at 60° C., and adjusted to pH 7. , 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 120°C to obtain coarse zirconium nitride powder.

Next, 20 g of the coarse zirconium nitride powder was dispersed in 5 liters of isopropanol and subjected to low-temperature wet media pulverization (media: alumina) for 60 minutes to obtain a zirconium nitride precursor powder. The temperature of isopropanol (dispersion medium) at this time was 5° C. or lower. Furthermore, after drying the above zirconium nitride precursor powder, it was fired at a temperature of 350° C. for 4 hours in an N ₂ gas atmosphere to obtain a zirconium nitride powder. This zirconium nitride powder was designated as Example 1.

<Examples 2 to 12 and Comparative Examples 1 to 10>
For the zirconium nitride powders of Examples 2 to 12 and Comparative Examples 1 to 10, coarse zirconium nitride powders were produced, pulverized, and fired by the methods shown in Table 1. Zirconium nitride powder was produced in the same manner as in Example 1 except for the production method, pulverization method, and firing method shown in Table 1. In addition, in the column of the method of producing coarse zirconium nitride powder in Table 1, "TM" indicates the thermite method, and "PZ" indicates the plasma method. In addition, in the column of pulverization method of coarse zirconium nitride powder in Table 1, "BM" is the bead mill method, and "JM" is the jet mill method. Furthermore, in the column of firing time/gas for the zirconium nitride precursor powder in Table 1, "N ₂ " is nitrogen gas, "He" is helium gas, and "Ar" is argon gas.

<Comparative test 1>
Regarding the zirconium nitride powders of Examples 1 to 12 and Comparative Examples 1 to 10, the volume resistivity in the state of compacted powder compacted at a pressure of 5 MPa, and the particle size when ultrasonically dispersed for 5 minutes in a diluted state with water The distribution _D90 was measured respectively. These results are shown in Table 1.

<Comparative test 2>
As shown in Table 1, 40 g of the zirconium nitride powders of Examples 1-11 and Comparative Examples 1-9 were dispersed in 200 ml of acrylic monomer or epoxy monomer to prepare a monomer dispersion. On the other hand, for 40 g of the zirconium nitride powder of Example 12 and Comparative Example 10, as shown in Table 1, an amine-based dispersant was added and dispersed in 200 ml of propylene glycol monomethyl ether acetate (PGMEA) solvent. After preparing black pigment dispersions, an acrylic resin was added to the black pigment dispersions at a mass ratio of black pigment:resin=3:7 and mixed to prepare a black composition. Then, 4 g of Irgacure 500 (photopolymerization initiator: manufactured by BASF) was added to the above monomer dispersion or black composition. Next, the monomer dispersion or the black composition is spin-coated on a glass substrate so that the film thickness after baking becomes the thickness shown in Table 1, and then pre-baking is performed to evaporate the solvent, thereby forming a photoresist film. formed. Furthermore, after exposing the photoresist film to a predetermined pattern shape through a photomask, the photoresist film is developed using an alkaline developer to dissolve and remove the unexposed portions of the photoresist film, and then post-baking is performed. A black film was formed by each. For these black films, the OD values of ultraviolet light (center wavelength 370 nm) and visible light (center wavelength 560 nm) were measured using a densitometer manufactured by Macbeth Co. under the product name D200 based on the above formula (1). At the same time, the volume resistivity (Ω·cm) of the black film was also measured. These results are shown in Table 1.

As is clear from Table 1, the zirconium nitride powders of Comparative Examples 1 and 10, that is, the zirconium nitride coarse powders were produced by the thermite method, but without pulverization, the zirconium nitride was heated to 350°C in a nitrogen gas atmosphere. The zirconium nitride powder that was fired for 4 hours had a volume resistivity of 1×10 ⁵ Ω·cm and an appropriate range (1×10 ⁷ Ω·cm) when compacted at a pressure of 5 MPa. above), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a state of being diluted with water was 30 µm, which was larger than the appropriate range (10 µm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 1 in the acrylic monomer was 1.0, which is smaller than the appropriate range (2.0 or more), and the volume resistivity was 1×10 ⁶ Ω·. cm, which is smaller than the appropriate range (1×10 ¹³ or more), and the coating film was not uniform. Furthermore, the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 10 in propylene glycol monomethyl ether acetate (PGMEA) was 1.9, which is smaller than the appropriate range (2.0 or more), and the volume resistivity was It was 6×10 ¹² Ω·cm, which is smaller than the appropriate range (1×10 ¹³ or more).

The zirconium nitride powder of Comparative Example 3, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by a bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5°C or less. The zirconium nitride powder, which was not calcined, had a particle size distribution _D90 of 9 μm when ultrasonically dispersed for 5 minutes in a state of being diluted with water, which was within the appropriate range (10 μm or less). The volume resistivity in the green compact state was 1×10 ⁶ Ω·cm, which was lower than the appropriate range (1×10 ⁷ Ω·cm or more). In addition, although the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 3 in the acrylic monomer was 2.1, which was within the appropriate range (2.0 or more), the volume resistivity was 5 × 10 ¹¹ Ω·cm, which is smaller than the appropriate range (1×10 ¹³ or more).

On the other hand, the zirconium nitride powders of Examples 1 and 12, that is, zirconium nitride coarse powders were prepared by the thermite method, and the zirconium nitride was pulverized by a bead mill method at a dispersion medium temperature of 5 ° C. or less (low-temperature wet media pulverization). The zirconium nitride powder sintered at a temperature of 350° C. for 4 hours in a nitrogen gas atmosphere has an appropriate volume resistivity of 1×10 ⁸ Ω·cm when compacted at a pressure of 5 MPa. 1×10 ⁷ Ω·cm or more, and the particle size distribution D ₉₀ after being diluted with water and subjected to ultrasonic dispersion for 5 minutes was 7 μm, which was within an appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 1 in the acrylic monomer was 2.1, which is within an appropriate range (2.0 or more), and the volume resistivity was 5×10 ¹³ Ω.・It was in the appropriate range (1×10 ¹³ or more). Furthermore, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 12 in propylene glycol monomethyl ether acetate (PGMEA) is 2.1, which is within an appropriate range (2.0 or more), and the volume resistivity was within an appropriate range (1×10 ¹³ or more) of 5×10 ¹³ Ω·cm.

The zirconium nitride powder of Example 9, that is, the zirconium nitride coarse powder was produced by the thermite method, and the zirconium nitride was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5 ° C., and then ground at 350 ° C. in a helium gas atmosphere. The zirconium nitride powder sintered for 4 hours at a temperature of 5 MPa has a volume resistivity of 8 × 10 ⁷ Ω cm in the compacted state, which is an appropriate range (1 × 10 ⁷ Ω cm or more), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a diluted state was 7 μm, which was within an appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 9 in an acrylic monomer was 2.2, which is within an appropriate range (2.0 or more), and the volume resistivity was 3×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

The zirconium nitride powder of Example 10, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride was pulverized by a bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5 ° C., and then ground at 350 ° C. in an argon gas atmosphere. The zirconium nitride powder sintered for 4 hours at a temperature of 5 MPa has a volume resistivity of 8 × 10 ⁷ Ω cm in the compacted state, which is an appropriate range (1 × 10 ⁷ Ω cm or more), and the particle size distribution _D90 when ultrasonically dispersed for 5 minutes in a diluted state was 9 μm, which was within an appropriate range (10 μm or less). In addition, the black film prepared by dispersing the zirconium nitride powder of Example 10 in an acrylic monomer had an OD value of 2.2, which is within an appropriate range (2.0 or more), and a volume resistivity of 3×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

On the other hand, although the zirconium nitride powder of Comparative Example 2, that is, the zirconium nitride coarse powder was produced by the plasma method, this zirconium nitride was not pulverized and was sintered at a temperature of 350° C. for 4 hours in a nitrogen gas atmosphere. The zirconium nitride powder has a volume resistivity of 3×10 ⁴ Ω·cm in the state of compacted powder solidified at a pressure of 5 MPa, which is lower than the appropriate range (1×10 ⁷ Ω·cm or more). The particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in this state was 14 μm, which was larger than the appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 2 in the epoxy monomer was 1.2, which is smaller than the appropriate range (2.0 or more), and the volume resistivity was 2×10 ⁶ Ω·. cm and smaller than the appropriate range (1×10 ¹³ or more).

The zirconium nitride powder of Comparative Example 4, that is, the zirconium nitride coarse powder was produced by a plasma method, and this zirconium nitride coarse powder was pulverized by a bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5° C. or less. The zirconium nitride powder, which was not calcined, had a particle size distribution _D90 of 5 μm when ultrasonically dispersed for 5 minutes in a state of being diluted with water, which was within the appropriate range (10 μm or less). The volume resistivity in the green compact state was 2×10 ⁴ Ω·cm, which was smaller than the appropriate range (1×10 ⁷ Ω·cm or more). In addition, although the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 4 in the epoxy monomer was 2.0, which was within an appropriate range (2.0 or more), the volume resistivity was 2 × 10 It was ¹⁰ Ω·cm, which is smaller than the appropriate range (1×10 ¹³ or more).

On the other hand, the zirconium nitride powders of Examples 2 and 4, that is, zirconium nitride coarse powders were produced by a plasma method, and the zirconium nitride coarse powders were pulverized by a bead mill method at a dispersion medium temperature of 5 ° C. or less (low-temperature wet media pulverization). The zirconium nitride powder that was later sintered at a temperature of 350° C. for 4 hours in a nitrogen gas atmosphere had a volume resistivity of 1×10 ⁷ Ω·cm in the state of compacted powder compacted at a pressure of 5 MPa. and an appropriate range (1 × 10 ⁷ Ω cm or more), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a state of being diluted with water is 5 µm respectively, which is within an appropriate range (10 µm or less). Ta. In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 2 in the epoxy monomer was 2.2, which is within an appropriate range (2.0 or more), and the volume resistivity was 2×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more). Furthermore, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 4 in an acrylic monomer is 2.3, which is within an appropriate range (2.0 or more), and the volume resistivity is 1×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Comparative Example 5, that is, the zirconium nitride coarse powder was produced by the thermite method. In the zirconium nitride powder that was pulverized (low-temperature wet media pulverization) at and then sintered at a temperature of 350 ° C. for 4 hours in a nitrogen gas atmosphere, the particle size distribution when ultrasonically dispersed for 5 minutes in a state diluted with water Although the D ₉₀ was 10 μm, which was within the appropriate range (10 μm or less), the volume resistivity in the state of compacted powder compacted at a pressure of 5 MPa was 7×10 ⁶ Ω·cm, which was within the appropriate range (1×10 ⁷ Ω·cm or more). In addition, although the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 5 in the acrylic monomer was 2.0, which was within an appropriate range (2.0 or more), the volume resistivity was 4 × 10 It was ¹² Ω·cm, which was smaller than the appropriate range (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Example 5, that is, the zirconium nitride coarse powder was prepared by the thermite method, and this zirconium nitride coarse powder was prepared at a dispersion medium temperature of 10 ° C., which is within the appropriate dispersion medium temperature range (10 ° C. or less). Zirconium nitride powder that was pulverized by a bead mill method (low-temperature wet media pulverization) and then sintered at a temperature of 350 ° C. for 4 hours in a nitrogen gas atmosphere has a volume in the state of a green compact solidified at a pressure of 5 MPa The resistivity is 8×10 ⁷ Ω·cm, which is within an appropriate range (1×10 ⁷ Ω·cm or more), and the particle size distribution D ₉₀ is 10 μm when ultrasonically dispersed for 5 minutes in a diluted state with water. range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 5 in the acrylic monomer was 2.0, which is within an appropriate range (2.0 or more), and the volume resistivity was 3×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Comparative Example 6, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5 ° C., but in a nitrogen gas atmosphere. Zirconium nitride fired at a temperature of 200° C., which is lower than the appropriate firing temperature range (250° C. to 550° C.), and held for 4 hours, which is within the appropriate firing time range (1 hour to 5 hours). The powder had a particle size distribution _D90 of 8 µm, which was within an appropriate range (10 µm or less) when it was diluted with water and ultrasonically dispersed for 5 minutes. The volume resistivity was 1×10 ⁶ Ω·cm, which was lower than the appropriate range (1×10 ⁷ Ω·cm or more). In addition, although the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 6 in the acrylic monomer was 2.0, which was within an appropriate range (2.0 or more), the volume resistivity was 1 × 10 It was ¹² Ω·cm, which was smaller than the appropriate range (1×10 ¹³ or more).

The zirconium nitride powder of Comparative Example 7, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5°C, but in a nitrogen gas atmosphere. , zirconium nitride fired at a temperature of 350 ° C., which is within the appropriate range of firing temperature (250 ° C. to 550 ° C.), and held for 0.5 hours, which is shorter than the appropriate range of firing time (1 hour to 5 hours) The powder had a particle size distribution _D90 of 7 µm, which was within an appropriate range (10 µm or less) when it was diluted with water and ultrasonically dispersed for 5 minutes. The volume resistivity was 3×10 ⁶ Ω·cm, which was lower than the appropriate range (1×10 ⁷ Ω·cm or more). In addition, although the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 7 in the acrylic monomer was 2.0, which was within an appropriate range (2.0 or more), the volume resistivity was 2 × 10 It was ¹² Ω·cm, which was smaller than the appropriate range (1×10 ¹³ or more).

The zirconium nitride powder of Comparative Example 8, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5°C, but in a nitrogen gas atmosphere. , The zirconium nitride powder fired at a temperature of 600 ° C., which is higher than the appropriate firing temperature range (250 ° C. to 550 ° C.), and held for 1 hour, which is within the appropriate firing time range (1 hour to 5 hours). , the volume resistivity in the state of a green compact solidified at a pressure of 5 MPa is 4 × 10 ⁶ Ω cm, which is smaller than the appropriate range (1 × 10 ⁷ Ω cm or more), and diluted with water for 5 minutes. The particle size distribution _D90 when ultrasonically dispersed was 14 μm, which was larger than the appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 8 in the acrylic monomer was 1.2, which is smaller than the appropriate range (2.0 or more), and the volume resistivity was 1×10 ⁹ Ω·. cm and smaller than the appropriate range (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Example 6, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by the bead mill method at a dispersion medium temperature of 5 ° C. (low temperature wet media pulverization). In a gas atmosphere, firing is performed at a temperature of 250 ° C., which is within the appropriate firing temperature range (250 ° C. to 550 ° C.), for 4 hours, which is within the appropriate firing time range (1 hour to 5 hours). The zirconium nitride powder has a volume resistivity of 3×10 ⁷ Ω·cm in the state of compacted powder solidified at a pressure of 5 MPa, which is within an appropriate range (1×10 ⁷ Ω·cm or more). The particle size distribution D ₉₀ after ultrasonic dispersion for 5 minutes in a diluted state was 8 μm, which was within an appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 6 in the acrylic monomer was 2.0, which is within an appropriate range (2.0 or more), and the volume resistivity was 2×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

The zirconium nitride powder of Example 7, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5 ° C., and then in a nitrogen gas atmosphere. , The zirconium nitride powder fired at a temperature of 350 ° C., which is within the appropriate range of firing temperature (250 ° C. to 550 ° C.), and for 1 hour, which is within the appropriate range of firing time (1 hour to 5 hours). In , the volume resistivity in the state of compacted powder solidified at a pressure of 5 MPa is 1×10 ⁷ Ω·cm, which is within an appropriate range (1×10 ⁷ Ω·cm or more), and in the state diluted with water, The particle size distribution D ₉₀ after ultrasonic dispersion for 5 minutes was 7 μm, which was within an appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 7 in an acrylic monomer was 2.0, which is within an appropriate range (2.0 or more), and the volume resistivity was 1×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

The zirconium nitride powder of Example 8, that is, the zirconium nitride coarse powder was produced by the thermite method, and the zirconium nitride coarse powder was pulverized by the bead mill method (low-temperature wet media pulverization) at a dispersion medium temperature of 5 ° C., and then in a nitrogen gas atmosphere. , The zirconium nitride powder fired at a temperature of 550 ° C., which is within the appropriate range of firing temperature (250 ° C. to 550 ° C.), and for 1 hour, which is within the appropriate range of firing time (1 hour to 5 hours). In , the volume resistivity in the state of compacted powder compacted at a pressure of 5 MPa is 1×10 ⁸ Ω·cm, which is within an appropriate range (1×10 ⁷ Ω·cm or more), and in the state diluted with water, The particle size distribution _D90 after ultrasonic dispersion for 5 minutes was 8 μm, which was within an appropriate range (10 μm or less). In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Example 8 in an acrylic monomer was 2.4, which is within an appropriate range (2.0 or more), and the volume resistivity was 1×10 ¹⁴ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Comparative Example 9, that is, the zirconium nitride coarse powder was produced by the thermite method. The zirconium nitride powder that was pulverized with a jet mill under pressure and then fired at a temperature of 350° C. for 4 hours in a nitrogen gas atmosphere had a volume resistivity of 2× in the state of a green compact solidified at a pressure of 5 MPa. 10 ⁶ Ω·cm, which is smaller than the appropriate range (1 × 10 ⁷ Ω·cm or more), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a diluted state with water is 14 µm, which is the appropriate range (10 µm or less). was bigger In addition, the OD value of the black film prepared by dispersing the zirconium nitride powder of Comparative Example 9 in the epoxy monomer was 1.3, which is smaller than the appropriate range (2.0 or more), and the volume resistivity was 1×10 ¹¹ Ω·. cm and smaller than the appropriate range (1×10 ¹³ or more).

On the other hand, the zirconium nitride powder of Example 3, that is, the zirconium nitride coarse powder was produced by the thermite method, and this zirconium nitride coarse powder was crushed at a crushing pressure of 0.5 MPa within an appropriate range (0.3 MPa or more). The zirconium nitride powder that was pulverized by a jet mill at a pulverization pressure and then sintered at a temperature of 350 ° C. for 4 hours in a nitrogen gas atmosphere has a volume resistivity of 2 in the state of a green compact solidified at a pressure of 5 MPa. × 10 ⁸ Ω·cm and within an appropriate range (1 × 10 ⁷ Ω·cm or more), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a diluted state with water is 6 µm and within an appropriate range (10 µm below). In addition, the black film prepared by dispersing the zirconium nitride powder of Example 3 in an epoxy monomer had an OD value of 2.2, which is within an appropriate range (2.0 or more), and a volume resistivity of 2×10 ¹⁴ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

The zirconium nitride powder of Example 11, that is, the zirconium nitride coarse powder was produced by the thermite method, and the zirconium nitride coarse powder was jetted at a pulverization pressure of 0.3 MPa, which is within an appropriate range (0.3 MPa or more). The zirconium nitride powder of Example 11 , which was milled and then sintered at a temperature of 350° C. for 4 hours in a nitrogen gas atmosphere, had a volume resistivity of 2 in the state of a green compact solidified at a pressure of 5 MPa. × 10 ⁷ Ω · cm and appropriate range (1 × 10 ⁷ Ω · cm or more), and the particle size distribution D ₉₀ when ultrasonically dispersed for 5 minutes in a diluted state with water is 10 μm and appropriate range (10 μm below). In addition, the black film prepared by dispersing the zirconium nitride powder of Example 11 in an epoxy monomer had an OD value of 2.4, which is within an appropriate range (2.0 or more), and a volume resistivity of 1×10 ¹³ Ω.・It was within the appropriate range of cm (1×10 ¹³ or more).

The zirconium nitride powder of the present invention can be used as a black pigment for obtaining a black film having high blackness and high insulating properties.

Claims (6)

It is in the state of secondary particles in which primary particles are aggregated, and does not contain low zirconium oxide and low zirconium oxynitride,
The volume resistivity is 10 ⁷ Ω·cm or more in the state of compacted powder solidified at a pressure of 5 MPa, and it is ultrasonically dispersed for 5 minutes in a state diluted with water or an alcohol having a carbon number within the range of 2 to 5. A zirconium nitride powder having a particle size distribution D ₉₀ of secondary particles of 10 µm or less. a step of producing coarse zirconium nitride powder having a specific surface area of 20 m ² /g to 90 m ² /g by a thermite method or a plasma synthesis method;
This zirconium nitride coarse powder is subjected to low-temperature wet media pulverization at a dispersion medium temperature of 10 ° C. or less, or jet mill pulverization at a gas pressure of 0.3 MPa or more, so that water or carbon atoms are in the range of 2 to 5 a step of producing a zirconium nitride precursor powder having a particle size distribution _D90 of 10 μm or less when ultrasonically dispersed for 5 minutes in an alcohol-diluted state;
The pulverized zirconium nitride precursor powder is fired in an inert gas atmosphere at a firing temperature of 250° C. to 550° C. for a firing time of 1 hour to 5 hours , thereby compacting it at a pressure of 5 MPa. A method for producing a zirconium nitride powder, comprising: producing a zirconium nitride powder having a bulk resistivity of 10 ⁷ Ω·cm or more. A monomer dispersion in which the zirconium nitride powder according to claim 1 is dispersed in an acrylic monomer or an epoxy monomer. A black composition comprising the zirconium nitride powder according to claim 1 dispersed in a dispersion medium as a black pigment and further mixed with a resin. A step of applying the monomer dispersion according to claim 3 to a substrate to form a coating film;
A method for producing a black film, comprising the step of thermally curing or ultraviolet curing the coating film to produce a black film. A step of applying the black composition according to claim 4 to a substrate to form a coating film;
A method for producing a black film, comprising the step of thermally curing or ultraviolet curing the coating film to produce a black film.