Titanium oxide particles contained in container, method for producing same, and titanium oxide particle storage container

Abstract

The invention discloses titanium oxide particles contained in a container, a method for producing the same, and a titanium oxide particle storage container. Provided are a container-packed titanium oxide particle capable of reducing a change in the moisture content of the titanium oxide particle during storage, a method for producing the same, and a titanium oxide particle storage container. Titanium oxide particles contained in a container include a container and titanium oxide particles contained in the container, the water vapor transmission rate of the container is 1.0 g / (m < 2 >. 24 h) or less under the conditions of a temperature of 40 DEG C and a relative humidity of 90% RH, and the total pore volume of the titanium oxide particles is 0.80 * 10 <-3 > m < 3 > / kg or less.

Description

Technical Field

[0001] The present disclosure relates to a container filled with titanium oxide particles, a method for manufacturing the same, and a storage container for titanium oxide particles. Background Art

[0002] The industrial application fields of titanium oxide are extremely wide. Representative examples include additives added to cosmetics, ultraviolet shielding materials, and silicone rubber. In recent years, titanium oxide has also been increasingly used as a raw material for barium titanate, which is used as a material for electronic components. Furthermore, "titanium oxide" is described as "titanium dioxide" in Japanese Industrial Standards (JIS), but since "titanium oxide" is widely used as a common name, titanium dioxide (TiO2) is abbreviated as titanium oxide in the present disclosure.

[0003] The surface of titanium oxide is basically covered with Ti atoms, O atoms, and OH groups chemically bonded to Ti atoms. Furthermore, water molecules are physically adsorbed to the OH groups through hydrogen bonds up to several layers, forming the moisture measured as the loss on drying.

[0004] Since this moisture is repeatedly adsorbed and desorbed on the surface of titanium oxide according to the humidity of the environment, it is easily affected by seasons or weather and varies. For example, in the case of synthesizing barium titanate by reacting BaO with TiO2, in order to strictly control the ratio of BaO to TiO2, it is necessary to completely dry and weigh titanium oxide immediately before synthesis, which significantly increases the burden on equipment or economy. Moreover, micronized titanium oxide has a large surface area per unit mass, that is, a large specific surface area, so the amount of adsorbed moisture is large, and the deviation in the amount at the time of raw material input is also large. Recently, there has also been a case where the requirement for micronization of titanium oxide has been strengthened, and the variation in the input amount and the accompanying decrease in the yield are more significant.

[0005] Patent Document 1 discloses that when packing fine titanium dioxide in a resin bag, water droplets with a spray droplet diameter of 5 to 500 μm are sprayed onto fine titanium dioxide with a BET specific surface area of 10 to 200 m 2 / g, the fine titanium dioxide carrying the water droplets is sealed in a resin bag, and the titanium dioxide is stored under conditions of a temperature of 5 to 50°C and a relative humidity of 60 to 95%, thereby reducing the variation in the amount of adsorbed moisture of the fine titanium dioxide.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent No. 5311707 Gazette Summary of the Invention

[0009] Titanium oxide used as a raw material for electronic materials such as barium titanate is being miniaturized, so it is difficult to control the moisture content. If the moisture content cannot be properly controlled, product quality fluctuations, performance degradation, or yield reduction will occur.

[0010] The present disclosure provides a container-packed titanium oxide particle capable of reducing fluctuations in the moisture content of titanium oxide particles during storage, a method for manufacturing the same, and a container for storing titanium oxide particles.

[0011] The present disclosure includes the following aspects.

[0012] [Aspect 1] A container-packed titanium oxide particle,

[0013] comprising a container and titanium oxide particles stored in the container,

[0014] wherein the water vapor transmission rate of the container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH, and the total pore volume of the titanium oxide particles is 0.80 × 10 -3 m 3 / kg or less.

[0015] [Aspect 2] The container-packed titanium oxide particle according to Aspect 1,

[0016] wherein the mesopore volume of the titanium oxide particles is 0.75 × 10 -3 m 3 / kg or less.

[0017] [Aspect 3] A container-packed titanium oxide particle,

[0018] comprising a container and titanium oxide particles stored in the container,

[0019] wherein the water vapor transmission rate of the container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH, and the mesopore volume of the titanium oxide particles is 0.75 × 10 -3 m 3 / kg or less.

[0020] [Aspect 4] The container-packed titanium oxide particle according to Aspect 3,

[0021] wherein the total pore volume of the titanium oxide particles is 0.80 × 10 -3 m 3 / kg or less.

[0022] [Aspect 5] The container-packed titanium oxide particle according to any one of Aspects 1 to 4,

[0023] wherein the container is a container having an aluminum layer.

[0024] [Solution 6] The container filled with titanium oxide particles according to any one of Solutions 1 to 5,

[0025] wherein the container is a container having an aluminum layer and a resin layer.

[0026] [Solution 7] The container filled with titanium oxide particles according to any one of Solutions 1 to 6,

[0027] wherein the container is a container having an aluminum laminated film.

[0028] [Solution 8] The container filled with titanium oxide particles according to any one of Solutions 1 to 7,

[0029] wherein the anatase content rate of the titanium oxide particles is 70% or more and 100% or less.

[0030] [Solution 9] The container filled with titanium oxide particles according to any one of Solutions 1 to 8,

[0031] wherein the BET specific surface area of the titanium oxide particles is 5 m 2 / g or more and 500 m 2 / g or less.

[0032] [Solution 10] The container filled with titanium oxide particles according to any one of Solutions 1 to 9,

[0033] wherein the total pore volume of the titanium oxide particles is 0.01×10 -3 m 3 / kg or more.

[0034] [Solution 11] The container filled with titanium oxide particles according to any one of Solutions 1 to 10,

[0035] wherein the change rate of the moisture content when the container filled with titanium oxide particles is stored in an environment of a temperature of 50°C and a relative humidity of 90% RH for 14 days is -2.0 mass% or more and 2.0 mass% or less.

[0036] [Solution 12] A titanium oxide particle storage container for storing titanium oxide particles having a total pore volume of 0.80×10 -3 m 3 / kg or less, wherein the water vapor transmission rate of the titanium oxide particle storage container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40°C and a relative humidity of 90% RH.

[0037] [Solution 13] A method for manufacturing a container filled with titanium oxide particles, comprising using titanium oxide particles having a total pore volume of 0.80×10 -3 m 3The step of storing titanium oxide particles of 0 / kg or less in a container and sealing the opening of the container, wherein the water vapor transmission rate of the container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH.

[0038] According to the present disclosure, it is possible to provide a container-packed titanium oxide particles, a method for manufacturing the same, and a titanium oxide particle storage container capable of reducing the variation in the moisture content of titanium oxide particles during storage. Detailed Description of the Invention

[0039] Hereinafter, modes for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not essential unless otherwise specifically stated. The same applies to numerical values and their ranges, which do not limit the present invention. In addition, various changes and modifications can be made by those skilled in the art within the scope of the technical idea of the present invention.

[0040] In the present disclosure, the numerical range indicated by "~" includes the numerical values before and after "~" as the minimum value and the maximum value, respectively.

[0041] In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of other stepwise-described numerical ranges. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0042] In the present disclosure, when there are multiple substances corresponding to each component, unless otherwise specified, the content rate and proportion of each component mean the total content rate and proportion of the multiple substances.

[0043] In the present disclosure, when there are multiple particles corresponding to each component, unless otherwise specified, the particle diameter of each component means a value for a mixture of the multiple particles.

[0044] In the present disclosure, regarding the term "layer", when observing the region where the layer exists, it includes not only the case where it is formed over the entire region but also the case where it is formed only in a part of the region.

[0045] In the present disclosure, the average thickness of a layer is the average of the thicknesses of the layer at any 10 locations.

[0046] In the present disclosure, "D50" is the particle diameter that becomes 50% in the volume-based cumulative particle size distribution obtained from the particle size distribution measured by the laser diffraction-scattering method.

[0047] [Container filled with titanium oxide particles]

[0048] The container filled with titanium oxide particles according to one embodiment includes a container and titanium oxide particles stored in the container. The water vapor transmission rate of the container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH, and the total pore volume of the titanium oxide particles is 0.80×10 -3 m 3 / kg or less.

[0049] The container filled with titanium oxide particles according to another embodiment includes a container and titanium oxide particles stored in the container. The water vapor transmission rate of the container is 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH, and the mesopore volume of the titanium oxide particles is 0.75×10 -3 m 3 / kg or less.

[0050] As a result of the research by the present inventors, it is known that when the total pore volume is 0.80×10 -3 m 3 / kg or less, or the mesopore volume is 0.75×10 -3 m 3 / kg or less of titanium oxide particles are stored in a container having a water vapor transmission rate of 1.0 g / (m 2 ·24 h) or less under the conditions of a temperature of 40 °C and a relative humidity of 90% RH, the moisture content of the titanium oxide particles is stabilized, that is, the change rate of the moisture content can be reduced.

[0051] In one embodiment, the change rate of the moisture content of the container filled with titanium oxide particles when stored in an environment of a temperature of 50 °C and a relative humidity of 90% RH for 14 days is -2.0 mass% or more and 2.0 mass% or less. According to this embodiment, the moisture content of the titanium oxide particles can be stably maintained for a long time. The change rate of the moisture content is preferably -1.5 mass% or more and 1.5 mass% or less, and more preferably -1.0 mass% or more and 1.0 mass% or less. In the present disclosure, the moisture content is measured by the method described in the examples.

[0052] <Container>

[0053] A. Water vapor transmission rate

[0054] The water vapor transmission rate through the container is 1.0 g / (m 2·Below 24 h), the permeation of moisture in the atmosphere into the container and the permeation of moisture in the container to the outside of the container are suppressed, and as a result, it is considered that the change in the moisture content of titanium oxide can be suppressed. From the same viewpoint, the water vapor transmission rate of the container is preferably 0.5 g / (m 2 ·24 h) or less, more preferably 0.3 g / (m 2 ·24 h) or less. In the present disclosure, the water vapor transmission rate of the container is measured by the method described in the examples.

[0055] The water vapor transmission rate of the container is preferably 0.001 g / (m 2 ·24 h) or more under the conditions of a temperature of 40°C and a relative humidity of 90% RH. Thereby, the manufacturing cost of the container can be suppressed, or an excessive increase in mass can be avoided, thereby improving the efficiency of transportation or storage. From the same viewpoint, the water vapor transmission rate of the container is more preferably 0.01 g / (m 2 ·24 h) or more, and further preferably 0.05 g / (m 2 ·24 h) or more.

[0056] B. Material

[0057] The material of the container is not particularly limited, and examples thereof include resin, rubber, metal, and carbon. The material of the container may be only one kind, or a combination of two or more kinds. From the viewpoint of low water vapor transmission rate, the container is preferably a container having a metal layer. The metal layer is preferably an aluminum layer. The container is more preferably a container having an aluminum layer and a resin layer. It is preferred that the entire region of the titanium oxide particle storage part of the container is covered with a metal layer such as an aluminum layer, or an aluminum layer and a resin layer.

[0058] The aluminum layer functions as a barrier layer for protecting the contents from the influence of gas, water vapor, light, etc. Examples of the aluminum layer include aluminum foil (Al foil) and aluminum vapor deposition film (Al film). From the viewpoint of being able to reduce the water vapor transmission rate of the container and being inexpensive in terms of cost, aluminum foil is preferred.

[0059] The thickness of the aluminum layer is preferably 1 to 25 μm, more preferably 4 to 15 μm, and further preferably 6 to 10 μm. When the thickness of the aluminum layer is 1 μm or more, the above-mentioned water vapor transmission rate can be easily ensured, and the impact durability can also be improved. When the thickness of the aluminum layer is 25 μm or less, the durability against bending can be improved.

[0060] The resin layer is not particularly limited as long as it has an effect of inhibiting the oxidation of the aluminum layer. Examples thereof include polyolefin resins such as polyethylene resin (PE), high-density polyethylene resin (HDPE), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (also simply referred to as LLDPE or LLD), and polypropylene resin (PP, OPP); polyester resins such as polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), and polyethylene naphthalate resin (PEN); polyamide resins; and their stretched films. From the viewpoints of strength or dead foldability, polyester resins, particularly polyethylene terephthalate resin (PET), are preferred. From the viewpoint of flexibility, polyethylene resin is preferred. From the viewpoints of having both strength and flexibility, a resin layer obtained by overlapping two or more polyethylene resin layers and a resin layer obtained by overlapping a polyethylene resin layer and a polyethylene terephthalate resin layer are more preferred.

[0061] The thickness of the resin layer is preferably 6 to 70 μm, more preferably 9 to 50 μm, and still more preferably 10 to 40 μm.

[0062] The container preferably has a structure in which the aluminum layer is sandwiched between resin layers, such as resin layer 1 / aluminum layer / resin layer 2. Thereby, the oxidation of the aluminum layer can be inhibited.

[0063] Each of resin layer 1 and resin layer 2 may be a single layer or a laminate of two or more layers. The resin layer preferably functions as a heat-sealing layer for sealing the edge portion of the aluminum layer.

[0064] C. Shape

[0065] The shape of the container is not particularly limited, and examples thereof include a cylindrical shape, a rectangular parallelepiped shape, and a bag shape. The container may be deformable or non-deformable. When transporting or storing titanium oxide particles, it is preferably deformable. From the viewpoints of light weight and excellent transportability or storability, a bag shape is preferred, and a vertical bag or a three-side bag is more preferred. The container is preferably a container having an aluminum laminated film formed by laminating a resin layer and an aluminum layer, and more preferably an aluminum laminated bag obtained by forming the aluminum laminated film into a bag shape.

[0066] <Titanium Oxide Particles>

[0067] A. Total Pore Volume

[0068] In one embodiment, the total pore volume of the titanium oxide particles is 0.80×10 -3 m 3 / kg or less. In this embodiment, it is easy to inhibit the moisture content of the titanium oxide particles. From the same viewpoint, the total pore volume of the titanium oxide particles is preferably 0.70×10 -3 m3 / kg or less, more preferably 0.50×10 -3 m 3 / kg or less. In the present disclosure, the total pore volume is measured by the method described in the examples.

[0069] The total pore volume of the titanium oxide particles is preferably 0.01×10 -3 m 3 / kg or more. When the titanium oxide particles of this embodiment are used as a synthesis raw material, other components easily penetrate into the pores of the titanium oxide particles, showing high reactivity. From the same viewpoint, the total pore volume of the titanium oxide particles is preferably 0.10×10 -3 m 3 / kg or more, more preferably 0.15×10 - 3 m 3 / kg or more.

[0070] B. Mesopore volume

[0071] In one embodiment, the mesopore volume of the titanium oxide particles is 0.75×10 -3 m 3 / kg or less. In this embodiment, it is easy to suppress the moisture content of the titanium oxide particles. From the same viewpoint, the mesopore volume of the titanium oxide particles is preferably 0.70×10 -3 m 3 / kg or less, more preferably 0.30×10 -3 m 3 / kg or less. In the present disclosure, the mesopore volume is measured by the method described in the examples.

[0072] The mesopore volume of the titanium oxide particles is preferably 0.01×10 -3 m 3 / kg or more. When the titanium oxide particles of this embodiment are used as a synthesis raw material, other components easily penetrate into the pores of the titanium oxide particles, showing high reactivity. From the same viewpoint, the mesopore volume of the titanium oxide particles is preferably 0.03×10 -3 m 3 / kg or more, more preferably 0.05×10 -3 m 3 / kg or more.

[0073] C. Anatase content

[0074] The anatase content rate of the titanium oxide particles is preferably 70% or more. Anatase-type titanium oxide particles are excellent in photoelectrochemical activity compared to other crystal systems such as rutile type. Therefore, titanium oxide particles having an anatase content rate of 70% or more are suitable as raw materials for electronic materials and the like. From the same viewpoint, the anatase content rate of the titanium oxide particles is more preferably 75% or more, and further preferably 78% or more. In the present disclosure, the anatase content rate is defined as the content rate of anatase-type crystals in the titanium oxide particles and is measured by the method described in the examples.

[0075] D. BET specific surface area

[0076] The BET specific surface area of the titanium oxide particles is preferably 5 m 2 / g or more and 500 m 2 / g or less, more preferably 10 m 2 / g or more and 480 m 2 / g or less, and further preferably 20 m 2 / g or more and 460 m 2 / g or less. If the BET specific surface area is 5 m 2 / g or more, highly reactive titanium oxide particles can be obtained. If the BET specific surface area is 500 m 2 / g or less, the aggregation of the titanium oxide particles is moderately suppressed, and the dispersibility can be improved. In the present disclosure, the BET specific surface area is measured by the method described in the examples.

[0077] E. D50

[0078] Titanium oxide particles generally form secondary particles aggregated from their primary particles in many cases. In the present disclosure, the particle size D50 of the titanium oxide particles in the aggregated state (an aggregate of primary particles and secondary particles) is measured using a laser diffraction particle size distribution apparatus, specifically, by the method described in the examples.

[0079] The D50 of the titanium oxide particles is preferably 10 μm or less. D50 corresponds to the effective diameter (aggregation diameter) when the titanium oxide particles are put into a solvent. The smaller D50 is, the better the dispersibility is. From the same viewpoint, the D50 of the titanium oxide particles is more preferably 5 μm or less, and further preferably 3 μm or less. The D50 of the titanium oxide particles can be 1 nm or more. The D50 at this time corresponds to the primary particle size. The D50 of the titanium oxide particles can be 3 nm or more, and can be 10 nm or more.

[0080] F. Primary particle size

[0081] The primary particle size of the titanium oxide particles is preferably 1 nm or more, more preferably 3 nm or more, and still more preferably 5 nm or more. When the primary particle size of the titanium oxide particles is 1 nm or more, excessive aggregation of the titanium oxide particles is easily suppressed. The primary particle size of the titanium oxide particles is preferably 100 nm or less, more preferably 60 nm or less, and still more preferably 20 nm or less. When the primary particle size of the titanium oxide particles is 100 nm or less, it can be advantageously used as a synthetic raw material for electronic components requiring fineness. In the present disclosure, the primary particle size is measured by the method described in the examples.

[0082] G. Tap density

[0083] The tap density of the titanium oxide particles is preferably 0.01 g / cm 3 or more and 0.80 g / cm 3 or less. When the tap density of the titanium oxide particles is 0.01 g / cm 3 or more, it is advantageous from the viewpoints of high density and transportation cost. From the same viewpoints, the tap density of the titanium oxide particles is more preferably 0.05 g / cm 3 or more, and still more preferably 0.08 g / cm 3 or more. When the tap density of the titanium oxide particles is 0.80 g / cm 3 or less, the dispersibility of the titanium oxide particles in water is excellent. From the same viewpoints, the tap density of the titanium oxide particles is more preferably 0.70 g / cm 3 or less, and still more preferably 0.60 g / cm 3 or less. In the present disclosure, the tap density is measured by the method described in the examples.

[0084] H. Chlorine (Cl) content

[0085] The Cl (chlorine atom) content of the titanium oxide particles is preferably 0.20 mass% or less. When such titanium oxide particles are used as a raw material, generation of by-products or aggregation of particles can be suppressed in subsequent processes. For example, when titanium oxide particles having a Cl content of 0.20 mass% or less are used as a raw material for BaTiO3 or the like, generation of a flux during firing can be suppressed. The molten flux tends to localize, and in the localized part, aggregation of particles occurs more frequently, and there may be a deviation in quality between this part and other parts. In addition, if particles aggregate, crystal growth of BaTiO3 particles may occur to form abnormal particles, resulting in a decrease in the dielectric properties of BaTiO3. From the viewpoint of more effectively suppressing the generation of the flux, the Cl content in the titanium oxide particles is more preferably 0.15 mass% or less, and still more preferably 0.10 mass% or less.

[0086] I. Content of other impurities

[0087] The Al content, S content, and Fe content of the titanium oxide particles are each preferably 0.05% by mass or less, more preferably 0.01% by mass or less. The Si content and C content in the titanium oxide particles are each preferably 0.5% by mass or less, more preferably 0.1% by mass or less. In this way, when using titanium oxide particles with few impurities as raw materials, the generation of by-products or the aggregation of particles can be suppressed in subsequent processes. For example, when obtaining a dielectric using such titanium oxide particles as raw materials, it is possible to suppress the deterioration of dielectric properties due to the presence of impurities. When using such titanium oxide particles for applications such as photocatalysts or solar cells, it is possible to prevent or suppress the reduction in transparency caused by coloring due to Fe, and in addition, it is possible to prevent or suppress the reduction in the function as a photocatalyst or solar cell caused by lattice defects due to Al, S, etc.

[0088] <Method for manufacturing titanium oxide particles>

[0089] The method for manufacturing titanium oxide particles will be described. The manufacturing method of titanium oxide is roughly classified into a gas phase method and a liquid phase method. These methods will be described in sequence, but are not limited to this description.

[0090] A. Gas phase method

[0091] The method for manufacturing titanium oxide particles based on the gas phase method includes: a reaction step of supplying a gas containing titanium tetrachloride, which is preferably heated to 600 °C or higher and less than 1100 °C, and an oxidizing gas heated to 600 °C or higher and less than 1100 °C to a reaction tube respectively to obtain a reaction gas; and a cooling step of cooling the reaction gas by introducing a cooling gas to obtain titanium oxide particles, and preferably further includes a dechlorination step.

[0092] (Reaction tube)

[0093] The reaction tube can be a horizontal reaction tube, but from the perspective of easily making the flow of various gases uniform, a vertical reaction tube is preferred, and a reaction tube with a circular cross-section is preferred. In the case of a circular vertical reaction tube, the preheated raw material gas and oxidizing gas are introduced from the upper end of the heated reaction tube to the lower part of the reaction tube through their respective supply pipes to generate a reaction gas. This step is called the reaction step. By providing a blowing port for the cooling gas on the inner wall of the reaction tube and blowing the cooling gas from there to mix with the reaction gas, the reaction gas is cooled. This step is called the cooling step.

[0094] The region in the reaction tube from the raw material gas inlet to the cooling gas injection port is referred to as the reaction region, and the region from the cooling gas injection port to the discharge port side is referred to as the cooling region. In the case of having a plurality of cooling gas injection ports, the region in the reaction tube from the raw material gas inlet to the first cooling gas injection port is referred to as the reaction region, and the region from the first cooling gas injection port to the discharge port side is referred to as the cooling region.

[0095] The cooled titanium oxide particles and the remaining gas are discharged to the outside at the lower part of the reaction tube. Furthermore, titanium oxide as a reaction product may also be contained in the reaction gas.

[0096] A-1. Reaction step

[0097] The temperature of the reaction region into which the titanium tetrachloride gas and the oxidizing gas are introduced is preferably 800 °C or higher and less than 1100 °C, more preferably 850 °C or higher and less than 1050 °C. By making the temperature of the reaction region high, the reaction is completed while these gases are mixed, so that uniform nucleation can be promoted and the reaction zone can be made small. When the temperature of the reaction region is 800 °C or higher, the reaction proceeds sufficiently and it is difficult for chlorine to remain inside the titanium oxide particles. When the temperature of the reaction region is less than 1100 °C, there is a tendency to be able to suppress the formation of rutile-type titanium oxide particles and increase the anatase content.

[0098] The oxidizing gas contains at least one of oxygen and water vapor, and may also contain other gases such as nitrogen. From the perspective of low cost, the oxidizing gas preferably contains water vapor.

[0099] A-2. Cooling step

[0100] The cooling gas is not particularly limited, and for example, air, nitrogen, or carbon monoxide can be used. From the viewpoint of improving the cooling effect, the temperature of the cooling gas is preferably 0 °C to 100 °C, more preferably 10 °C to 90 °C. Spray water can also be used in combination with the cooling gas.

[0101] A-3. Dechlorination step

[0102] The produced titanium oxide particles are preferably subjected to dechlorination treatment in the dechlorination process. For the dechlorination of titanium oxide particles by heating, it is preferred to heat while bringing water vapor into contact with the titanium oxide particles in such a way that the mass ratio of water to titanium oxide particles (mass of water vapor / mass of titanium oxide particles) is 0.01 or more, preferably 0.04 or more, and to heat to a temperature of 200°C or more and 550°C or less, preferably 250°C or more and 450°C or less. By keeping the temperature at 550°C or less, sintering of the titanium oxide particles can be suppressed and the primary particle size can be made uniform. By keeping the temperature at 200°C or more, the efficiency of dechlorination can be increased. If the mass ratio of water to titanium oxide particles is 0.01 or more, particle growth can be effectively suppressed. The mass ratio of water to titanium oxide particles is preferably 0.01 or more and 3 or less, more preferably 0.04 or more and 2 or less, and still more preferably 0.2 or more and 1.8 or less.

[0103] Since the titanium oxide particles of the present disclosure hardly contain chlorine inside the particles and most of the chlorine exists on the particle surface, a wet method can also be used for dechlorination, for example, removing chlorine by water washing. Examples of the wet method include: a method in which titanium oxide particles are suspended in pure water and chlorine transferred to the liquid phase is separated outside the system using an ultrafiltration membrane, a reverse osmosis membrane, a filter press, or the like.

[0104] B. Liquid phase method

[0105] The method for producing titanium oxide particles based on the liquid phase method includes: a reaction step of hydrolyzing an aqueous solution of titanium tetrachloride, and a cooling step of cooling the subsequent reaction solution, and preferably further includes a dechlorination step.

[0106] B-1. Reaction step

[0107] When an aqueous solution of titanium tetrachloride at room temperature (about 20°C) is preferably mixed with water preheated to 80°C or more, and the resulting mixture is heated and maintained at 80°C or more, turbidity can be observed during mixing, and titanium oxide particles can be obtained immediately after mixing. The preheating temperature of the water is preferably 80°C or more and below the boiling point, more preferably 90°C or more and below the boiling point. By setting the preheating temperature of the water at 80°C or more, hydrolysis of titanium tetrachloride can be promoted.

[0108] Mixing can be carried out using a stirring device. As the stirring device, a generally widely used rotary vane mixer can be used. The shape of the rotary vane can be a general shape such as a propeller shape, a turbine shape, or a comb shape. To improve the stirring efficiency, two or more mixers can also be installed in the reaction tank, or a baffle can be provided. Not limited to a batch reactor, a continuous tank-type reactor or a tubular reactor having a structure in which the reaction tank is a continuous tank and titanium tetrachloride and water are continuously introduced while the reaction solution is taken out on the opposite side of the introduction port can also be used.

[0109] B-2. Cooling process

[0110] The time from the completion of the mixing of the titanium tetrachloride aqueous solution and water to cooling to less than 60°C is preferably within 15 minutes, more preferably within 10 minutes, and still more preferably within 5 minutes. If the mixture is maintained at 60°C or higher for a long time, there may be a case where the primary particles formed are joined to each other, the secondary particles grow, and the dispersibility decreases. By cooling the mixture to less than 60°C immediately after the primary particles are formed, the growth of the secondary particles can be suppressed, and particles with high dispersibility can be obtained.

[0111] B-3. Dechlorination process

[0112] In the dechlorination process, the same method as in the dechlorination process in the gas phase method can be used.

[0113] <Method for manufacturing container-packed titanium oxide particles>

[0114] The method for manufacturing container-packed titanium oxide particles includes: a process of storing the titanium oxide particles in the container and sealing the opening of the container. As a sealing means, the opening of the container can be sealed by thermocompression bonding using a sealer.

[0115] [Examples]

[0116] Hereinafter, examples and comparative examples will be specifically described, but the present invention is not limited to these examples.

[0117] <Container>

[0118] The container is a bag-shaped container made of a sheet having the following structure. In the description of the sheet structure, the layer described first is the outermost layer, the layer described last is the innermost layer, and the description order represents the lamination order. Container 1, Container 2, and Container 3 are bags made of an aluminum laminated film.

[0119] Container 1: PET film (thickness 12 μm) / PE film (thickness 15 μm) / Al foil (thickness 9 μm) / PE film (thickness 15 μm) / LLDPE film (thickness 30 μm), water vapor transmission rate 0.06 g / (m 2 ·24h)

[0120] Container 2: PET film (thickness 12 μm) / PE film (thickness 15 μm) / Al foil (thickness 7 μm) / SPE (polyethylene (extrusion lamination)) film (thickness 15 μm) / PE film (thickness 40 μm), water vapor transmission rate 0.1 g / (m 2 ·24h)

[0121] Container 3: PET film (thickness 12 μm) / Al film (thickness 0.02 μm) / LDPE film (thickness 65 μm), water vapor transmission rate 5.9 g / (m 2 ·24 h)

[0122] Container 4: LDPE film (thickness 70 μm), water vapor transmission rate 15 g / (m 2 ·24 h)

[0123] The water vapor transmission rate of the container was determined by JIS K 7129-2:2019 "Method for determining water vapor transmission rate of plastic films and sheets - Part 2: Infrared sensor method".

[0124] <Measurement method>

[0125] A. Total pore volume

[0126] For 0.1 g of titanium oxide particles pre-treated by heating to 180 °C and flowing nitrogen for 20 minutes, the total pore volume was measured using NOVA4200e manufactured by Quantachrome Corporation and nitrogen in accordance with JIS Z8831-3:2010 "Method for measuring micropores based on gas adsorption". The lower limit of measurement was 1.1 nm, and the upper limit was the value when the relative pressure P / P0, which is the ratio of the measurement pressure P to the saturated vapor pressure P0, reached 0.99.

[0127] B. Mesopore volume

[0128] For 0.1 g of titanium oxide particles pre-treated by heating to 180 °C and flowing nitrogen for 20 minutes, the mesopore volume was measured using NOVA4200e manufactured by Quantachrome Corporation and nitrogen in accordance with JIS Z8831-3:2010 "Method for measuring micropores based on gas adsorption". The lower limit of measurement was 2 nm, and the upper limit was 50 nm.

[0129] C. Anatase content

[0130] The content of anatase-type crystals (anatase content) in titanium oxide particles was measured by powder X-ray diffraction method. Specifically, for the dried titanium oxide particles, using "X'pert PRO" manufactured by PANalytical as the measuring device, a copper target, and Cu-Kα1 ray, X-ray diffraction measurement was carried out under the conditions of tube voltage 45 kV, tube current 40 mA, measurement range 2θ = 10 - 80 deg (degree), sampling amplitude 0.0167 deg, and scanning speed 0.0192 deg / s. The peak height (Ha) of the maximum peak corresponding to the anatase-type crystal, the peak height (Hb) of the maximum peak corresponding to the brookite-type crystal, and the peak height (Hr) of the maximum peak corresponding to the rutile-type crystal were obtained, and the content of anatase-type crystals (anatase content) in the titanium oxide particles was calculated using the following formula.

[0131] Anatase content (%) = {Ha / (Ha + Hb + Hr)} × 100

[0132] D.BET specific surface area

[0133] According to JIS R 1626:1996 "Method for Measuring Specific Surface Area of Fine Ceramic Powders by Gas Adsorption BET Method", measurement was carried out using a fully automatic BET specific surface area measuring device ("Macsorb HM model-1208", Mount Tech Co., Ltd.). For 0.1 g of titanium oxide particles pre-treated by heating to 180 °C and flowing nitrogen for 20 minutes, using the BET three-point method and nitrogen as the adsorbate, the BET specific surface area was measured. Regarding the application range of the BET method, the range of the ratio of the measurement pressure P to the saturated vapor pressure P0, i.e., the relative pressure P / P0, was set to 0.00 - 0.95.

[0134] E.D50

[0135] 0.05 g of titanium oxide particles, 50 mL of pure water, and 100 μL of 10 mass% sodium hexametaphosphate aqueous solution were added to a 100 mL tall beaker to prepare a slurry, and a polytetrafluoroethylene rod was used to stir the slurry in the tall beaker, and ultrasonic waves (50 KHz, 100 W) were irradiated for 3 minutes. Stirring was carried out only for 1 minute starting from the start of ultrasonic irradiation. The ultrasonic bath was a box-type with an inner size of 230 mm × 200 mm × 152 mm, and the water volume was 450 mL. The position of the tall beaker during ultrasonic irradiation was set near the center of the ultrasonic bath. Using this slurry as a sample, the particle size D50 at 50% in the volume-based cumulative particle size distribution was measured using a laser diffraction particle size distribution measuring device (Microtrac MT3300EXII, Microtrac Co.).

[0136] F. Primary particle size

[0137] 1 g of titanium oxide particles was put into 100 mL of ethanol, and after ultrasonic irradiation (30 W, 5 min), the dispersion was sampled with a Pasteur pipette, and about 0.05 g was dropped onto aluminum foil. It was naturally dried in the laboratory atmosphere, the aluminum foil was fixed to the SEM specimen stage, and measurement was carried out using a field emission scanning electron microscope (S-5500, Hitachi High-Technologies Corporation). As the measurement conditions for SEM, the acceleration voltage was set to 2.0 kV. An image was taken so that the number of primary particles in each field of view was 200 to 300, and for about 200 to 300 particles on this image, the primary particle size (equivalent circle diameter, specifically, Heywood diameter) of each particle was obtained using image analysis software. The image analysis software used Particle Analysis Ver3 of Sumitomo Metal Technology Corporation or Mac-View Ver3 of Mount-Tech Co., Ltd. The same operation was performed for other fields of view of the same specimen, and the same operation was repeated until the total number of particles used for the calculation of primary particles exceeded at least 1000. The particle size at which the cumulative total value of the reference amount from the smaller particle size side in the cumulative particle size distribution obtained under the obtained number basis became 50% of the total cumulative value was calculated as the primary particle size.

[0138] G. Tap density

[0139] As a tap density measuring device, Powder Tester PT-X (Hosokawa Micron Corporation) was used. Titanium oxide particles were filled up to the upper end of a 100 mL fixed-volume cup, the lid was put on, and after tapping the container for 3 minutes under the conditions of a tapping stroke of 70 mm and 180 times, the powder volume and mass were measured, and the volume density was thus obtained.

[0140] H. Chlorine (Cl) content

[0141] The Cl content in the titanium oxide particles was measured by potentiometric titration with silver nitrate. Specifically, 0.5 g of titanium oxide particles was weighed. Then, a silver nitrate solution (concentration 0.02 mol / L) was added dropwise to the solution of the titanium oxide particles to measure the potential difference, and thus the mass of chlorine atoms in the solution was obtained, and the chlorine content (mass%) was calculated.

[0142] I. Content of other impurities

[0143] The measurement methods for each impurity are as follows.

[0144] Fe: Atomic absorption spectrometry (Z-2300 type atomic absorption spectrophotometer, Hitachi High-Technologies Corporation)

[0145] Al, Si: Fluorescent X-ray analysis method (XRF) (Simaltrex 10, Rigaku Corporation)

[0146] C, S: Combustion-infrared absorption method using a high-frequency induction heating furnace

[0147] J. Moisture content

[0148] Using a heated drying type moisture meter MX-50 (A&D Company, Limited), after heating 2 g of titanium oxide powder to 200 °C in an air atmosphere, infrared heating was carried out at 120 °C until the mass change became 0.01 mass% or less. The mass of the titanium oxide powder was measured, and the entire mass reduction was calculated as moisture.

[0149] Synthesis Example 1

[0150] Using a vertical reaction tube with a circular cross-section, a mixed raw material gas (G1) with a titanium tetrachloride flow rate of 16.9 Nm 3 / h and a nitrogen flow rate of 18.0 Nm 3 / h was heated to 1030 °C and introduced from the top of the reaction tube at a total flow rate of 34.9 Nm 3 / h. And an oxygen flow rate of 7.8 Nm 3 / h, a steam flow rate of 26.2 Nm 3 / h and a nitrogen flow rate of 0.1 Nm 3 / h of a mixed oxidizing gas (G2) was heated to 820 °C and introduced from the top of the reaction tube at a total flow rate of 34.1 Nm 3 / h to generate a reaction gas. Nitrogen was introduced as a purge medium from the inner wall of the reaction tube in the reaction zone (1050 °C). In the cooling zone, air at 25 °C was introduced as a cooling gas to obtain titanium oxide particle raw materials. Then, the titanium oxide particle raw materials were collected at the lower part of the reaction tube using a bag filter made of polytetrafluoroethylene.

[0151] The obtained titanium oxide particle raw materials were introduced into a cylindrical rotary heating furnace and dechlorinated under the conditions where the mass ratio of water vapor mixed with air to the titanium oxide particle raw materials (mass of water vapor / mass of titanium oxide particle raw materials) was 0.06 and the temperature was 450 °C to obtain titanium oxide particles 1.

[0152] Synthesis Example 2

[0153] Using a vertical reaction tube with a circular cross-section, a mixed raw material gas (G1) with a titanium tetrachloride flow rate of 3.7 Nm 3 / h and a nitrogen flow rate of 25.3 Nm 3 / h was heated to 1030 °C and introduced at a total flow rate of 29.0 Nm 3is introduced from the top of the reaction tube at / hour, and the oxygen flow rate is 3.2 Nm 3 / hour, the steam flow rate is 31.9 Nm 3 / hour, and the nitrogen flow rate is 0.3 Nm 3 / hour of the mixed oxidizing gas (G2) is heated to 910 °C and introduced from the top of the reaction tube at a total flow rate of 35.4 Nm 3 / hour to generate reaction gas. Nitrogen is introduced as a purge medium from the inner wall of the reaction tube in the reaction zone (850 °C). In the cooling zone, air at 25 °C is introduced as a cooling gas to obtain a titanium oxide particle raw material. Then, the titanium oxide particle raw material is collected at the lower part of the reaction tube using a bag filter made of polytetrafluoroethylene.

[0154] The obtained titanium oxide particle raw material is introduced into a cylindrical rotary heating furnace, and dechlorination is carried out under the conditions that the mass ratio of water vapor mixed with air to the titanium oxide particle raw material (mass of water vapor / mass of titanium oxide particle raw material) is 0.06 and the temperature is 450 °C to obtain titanium oxide particles 2.

[0155] Synthesis Example 3

[0156] 690 mL of ion-exchanged water is charged into a reaction tank equipped with a comb-shaped stirrer and preheated to 95 °C. The stirring speed is set to about 300 rpm. While heating and maintaining the temperature at 95 °C, 50 g of an aqueous titanium tetrachloride solution (Ti concentration: 18% by mass) at room temperature (20 °C) is added dropwise to the reaction tank over 30 seconds, and stirring and mixing are carried out in the reaction tank. Since it is immediately and uniformly mixed after adding the aqueous titanium tetrachloride to the water droplets, the dropping time can be approximated to the mixing time. After all the titanium tetrachloride has been added dropwise, the mixed solution is maintained at 95 °C for 4 minutes. Then, the reaction tank is cooled to 50 °C in an ice bath in less than 1 minute. At this time, it takes 40 seconds until the temperature in the reaction tank reaches 60 °C. Hydrochloric acid generated during the reaction is removed using an electrodialysis device to obtain a titanium oxide sol. After drying the titanium oxide sol using a dryer at 100 °C, it is crushed using a mortar to obtain titanium oxide particles 3.

[0157] Examples 1 to 4, Comparative Examples 1 to 3

[0158] One hundred grams of one of titanium oxide particles 1 to 3 was filled into one of containers 1 to 4, and sealed by thermocompression bonding with a sealer. Subsequently, after the container filled with titanium oxide particles was placed in an environment of 50°C and 90% RH for a specified time, the moisture content of the titanium oxide particles was measured. If the moisture content change rate at 14 days of storage is -2.0 mass% or more and 2.0 mass% or less, it indicates that the moisture content is stable. For the measurements on the 5th, 7th, 10th, 14th, and 15th days, additional containers filled with titanium oxide were prepared, and the titanium oxide in the additional containers was measured each time. The measured samples and results are shown in Table 2. In Table 2, "-" indicates not measured.

[0159] Table 1

[0160]

[0161] Table 2

[0162]

[0163] For Examples 1 to 4 in which one of titanium oxide particles 1 to 3 was stored in Container 1 or 2 with a water vapor transmission rate of 1.0 g / (m 2 ·24 h) or less under the conditions of 40°C and 90% RH, the change rate of the moisture content was within ±1.2%, and it could be stored in a state with a stable moisture content. Regarding Examples 3 and 4, by linearly interpolating the moisture content after 10 days and 15 days, it was estimated that even after 14 days, the moisture content was the same as that after 10 days and 15 days.

[0164] On the other hand, for Comparative Examples 1 to 3 in which titanium oxide particle 1 or 2 was stored in Container 3 or Container 4 with a water vapor transmission rate exceeding 1.0 g / (m 2 ·24 h) under the conditions of 40°C and 90% RH, the change rate of the moisture content was ±43.8% or more, and the moisture content increased significantly. Regarding Comparative Example 3, by linearly interpolating the moisture content after 10 days and 15 days, it was estimated that the moisture content after 14 days was 9.89 mass%, and the change rate was 190.8%.

Claims

1. A container containing titanium oxide particles, comprising a container and titanium oxide particles contained in the container, The water vapor permeability of the container is 1.0 g / (m 2 ·24h) or less, the total pore volume of the titanium oxide particles is 0.80×10 -3 m 3 / kg or less.

2. The container-packed titanium oxide particles according to claim 1, The mesopore volume of the titanium oxide particles is 0.75×10 -3 m 3 / kg or less.

3. A container containing titanium oxide particles, comprising a container and titanium oxide particles contained in the container, The water vapor permeability of the container is 1.0 g / (m 2 ·24h) or less, the mesopore volume of the titanium oxide particles is 0.75×10 -3 m 3 / kg or less.

4. The container-packed titanium oxide particles according to claim 3, The total pore volume of the titanium oxide particles is 0.80×10 -3 m 3 / kg or less.

5. The container-packed titanium oxide particles according to any one of claims 1 to 4, The container is a container having an aluminum layer.

6. The container-packed titanium oxide particles according to any one of claims 1 to 4, The container is a container having an aluminum layer and a resin layer.

7. The container-packed titanium oxide particles according to any one of claims 1 to 4, The container is a container having an aluminum laminate film.

8. The container-packed titanium oxide particles according to any one of claims 1 to 4, The titanium oxide particles have an anatase content of 70% or more and 100% or less.

9. The container-packed titanium oxide particles according to any one of claims 1 to 4, The BET specific surface area of ​​the titanium oxide particles is 5 m 2 / g and above and 500m 2 / g or less.

10. The container-packed titanium oxide particles according to any one of claims 1 to 4, The total pore volume of the titanium oxide particles is 0.01×10 -3 m 3 / kg or more.

11. The container-packed titanium oxide particles according to any one of claims 1 to 4, When the container-filled titanium oxide particles are stored for 14 days in an environment of a temperature of 50° C. and a relative humidity of 90% RH, the change rate of the moisture content is −2.0% by mass or more and 2.0% by mass or less.

12. A titanium oxide particle storage container for storing a titanium oxide particle having a total pore volume of 0.80×10 -3 m 3 / kg or less titanium oxide particle storage container, wherein the water vapor permeability of the titanium oxide particle storage container is 1.0 g / (m 2 24h) or less.

13. A method for producing container-filled titanium oxide particles, comprising: -3 m 3 / kg or less titanium oxide particles are stored in a container and the opening of the container is sealed, wherein the water vapor permeability of the container is 1.0 g / (m 2 24h) or less.

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