Titanate compound fine particle powder and method of production therefor

Abstract

An embodiment of the present invention pertains to a titanate compound fine particle powder containing a modified titanate compound powder. Specifically, the titanate compound fine particle powder provides a titanate compound powder dispersion capable of suppressing, with a small amount of a polymer dispersant, the aggregation and re-aggregation of particles. Another embodiment of the present invention pertains to a titanate compound powder dispersion that exhibits excellent dispersibility in various solvents. Still another embodiment of the present invention pertains to an economically and industrially advantageous method for producing a titanate compound fine particle powder. Provided is a titanate compound fine particle powder that contains a modified titanate compound powder including cellulose nanofibers and a titanate compound powder. The cellulose nanofibers and the titanate compound adhere to or adsorb to each other. The ratio of the total carbon content of the titanate compound fine particle powder and the BET specific surface area of the titanate compound fine particle powder is 0.006 or less. Also provided is a method for producing the titanate compound fine particle powder, the method including mixing an unmodified titanate compound powder and the cellulose nanofibers, and then drying the mixture.

Description

Titanate compound fine particle powder and method for producing the same 【0001】 This disclosure relates to titanate compound fine particle powder and a method for producing the same. 【0002】 In recent years, with the miniaturization, thinning, shortening, and performance enhancement of electronic components, there has been a growing demand for titanate compound powders and dispersions containing titanate compound powders (titanate compound powder dispersions) for applications such as dielectric materials in multilayer ceramic capacitors, and high refractive index materials used in anti-reflective coatings or lenses where transparency is required. 【0003】 Generally, dispersing titanate compound powders in a solvent requires the use of a large amount of dispersant and prolonged mechanical shearing. 【0004】 However, in multilayer ceramic capacitor (MLCC) applications, if a large amount of dispersant is included, some of the dispersant remains as carbon when the green sheet is fired. This causes voids to form in the film. These voids degrade the properties of the MLCC. In optical applications, a large amount of dispersant can cause a decrease in refractive index. 【0005】 Therefore, there is a need to disperse the titanate compound powder with the smallest possible amount of dispersant. 【0006】 In addition, there is a need for titanate compound powder dispersions that do not undergo particle re-aggregation over time, i.e., dispersion stability, and for titanate compound powders that provide such dispersions. 【0007】 Japanese Patent Publication No. 2022-153928 【0008】 Japanese Patent Publication No. 2018-155746 【0009】 Patent Document 1 describes the preparation of a composition for ceramic green sheet binders, which involves adding a ceramic powder such as titanium dioxide or barium titanate, a binder such as polyvinyl acetal resin or (meth)acrylic resin, and nanocellulose. 【0010】However, simply dispersing nanocellulose and ceramic powder together in a solvent does not allow for obtaining a titanate compound powder dispersion that exhibits excellent dispersion stability with a small amount of dispersant. 【0011】 Furthermore, Patent Document 2 describes an oxide semiconductor nanoparticle assembly. In this nanoparticle assembly, multiple oxide semiconductor nanoparticles are linearly and continuously supported on cellulose nanofibers. 【0012】 However, the proportion of cellulose nanofibers relative to the oxide semiconductor nanoparticles in Patent Document 2 is very high. Therefore, with a small amount of dispersant, the dispersibility and dispersion stability of the dispersion containing nanoparticles are insufficient. 【0013】 To solve the aforementioned problems, numerous prototypes and experiments were conducted through trial and error. As a result, it was successful to obtain a titanate compound fine particle powder that provides a dispersion with excellent dispersibility in various solvents even with a small amount of dispersant. Furthermore, it was also successful to obtain a dispersion that can stably maintain its dispersion state using this titanate compound fine particle powder. Thus, this embodiment can solve the aforementioned technical problems. Moreover, this embodiment also provides an economical and industrially advantageous method for producing titanate compound fine particle powder. 【0014】 The aforementioned technical problems can be solved by this embodiment as follows. 【0015】 The titanate compound fine particle powder according to this embodiment includes a modified titanate compound powder. 【0016】 The modified titanate compound powder comprises cellulose nanofibers and titanate compound powder. The cellulose nanofibers and the titanate compound powder are attached to or adsorbed to each other. The ratio of the total carbon content of the titanate compound fine particle powder to the BET specific surface area of ​​the titanate compound fine particle powder is 0.006 or less (first embodiment). 【0017】The titanate compound powder dispersion according to this embodiment comprises the titanate compound fine particle powder according to the first embodiment and a solvent (second embodiment). 【0018】 The titanate compound powder dispersion according to the second embodiment may further contain a polymer dispersant (third embodiment). 【0019】 The titanate compound powder resin composition according to this embodiment comprises the titanate compound fine particle powder and resin according to the first embodiment (fourth embodiment). 【0020】 The method for producing the titanate compound fine particle powder according to this embodiment includes mixing an unmodified titanate compound powder with cellulose nanofibers, drying the mixture of the unmodified titanate compound powder and the cellulose nanofibers, and causing the cellulose nanofibers and the unmodified titanate compound powder in the mixture to adhere to or adsorb to each other (Fifth Embodiment). 【0021】 The method for producing the titanate compound powder dispersion according to this embodiment includes mixing the titanate compound fine particle powder obtained by the production method according to the fifth embodiment with a polymer dispersant and a solvent (sixth embodiment). 【0022】 The titanate compound fine particle powder according to this embodiment includes a modified titanate compound powder containing cellulose nanofibers and titanate compound powder that are attached to or adsorbed to each other. The ratio of the total carbon content of the titanate compound fine particle powder to the BET specific surface area of ​​the titanate compound fine particle powder is 0.006 or less. Therefore, the titanate compound fine particle powder according to this embodiment can provide a dispersion with good dispersibility even when the amount of dispersant is small. 【0023】 Furthermore, according to this embodiment, a dispersion is obtained that contains the titanate compound fine particle powder and a polymer dispersant. This dispersion has low re-aggregation properties and excellent dispersion stability in various solvents. 【0024】Therefore, the titanate compound fine particle powder, titanate compound powder dispersion, and titanate compound powder resin composition according to this embodiment can be suitably used, for example, in materials for MLCC applications, anti-reflective coatings, and lenses, as high refractive index materials requiring high transparency. 【0025】 Furthermore, the method for producing the titanate compound fine particle powder and titanate compound powder dispersion according to this embodiment does not require any special equipment. As a result, the powder and its dispersion can be produced in a short time. Therefore, the method for producing the titanate compound fine particle powder and titanate compound powder dispersion according to this embodiment is highly productive. 【0026】 This embodiment will be described in detail as follows: 【0027】 First, the titanate compound fine particle powder according to this embodiment will be described. 【0028】 The titanate compound fine particle powder according to this embodiment includes a modified titanate compound powder. In the modified titanate compound powder, cellulose nanofibers and the titanate compound powder are attached to or adsorbed to each other. Furthermore, the ratio of the total carbon content of the titanate compound fine particle powder to the BET specific surface area of ​​the titanate compound fine particle powder is 0.006 or less. 【0029】 As described above, the ratio of the total carbon content of the titanate compound fine particle powder according to this embodiment to the BET specific surface area of ​​the titanate compound fine particle powder is (total carbon content (weight%) / BET specific surface area (m²) ２ The ratio ( / g) is 0.006 or less. If the ratio exceeds 0.006, a dispersion with good dispersion stability may not be obtained if the amount of dispersant is reduced to 10% by weight or less. The ratio is preferably 0.0055 or less, more preferably 0.0045 or less. The ratio does not include 0. The lower limit of the ratio is not particularly limited, but a preferred ratio is 0.0001 or more. A more preferred ratio is 0.0005 or more. An even more preferred ratio is 0.001 or more. 【0030】 The BET specific surface area of ​​the titanate compound fine particle powder according to this embodiment is preferably 30 m².２ / g or more, more preferably 35m ２ It is 1 / g or more. The BET specific surface area is 30 m². ２ Below 1g, transparency may not be obtained in high refractive index applications. The upper limit of the BET specific surface area is not particularly limited. A preferred upper limit for the BET specific surface area is 100m². ２ It is approximately / g 【0031】 The total carbon content of the titanate compound fine particle powder according to this embodiment is preferably 0.01 to 1% by weight. When the total carbon content is within this range, the dispersion containing the titanate compound fine particle powder exhibits excellent particle dispersibility in the solvent and a high refractive index for optical applications. The total carbon content is more preferably 0.05 to 0.8% by weight, and even more preferably 0.1 to 0.6% by weight. 【0032】 Here, the average primary particle size of the unmodified titanate compound powder used as a raw material for the titanate compound fine particle powder according to this embodiment is preferably 10 nm to 70 nm (10 to 70 nm), more preferably 15 to 65 nm, and even more preferably 20 to 60 nm. When the average primary particle size is less than 10 nm, it is difficult to industrially manufacture the unmodified titanate compound powder using the current manufacturing method. Furthermore, with unmodified titanate compound powders larger than 70 nm, transparency may not be obtained in applications as a high refractive index material. 【0033】 The titanate compound that is a component of the unmodified titanate compound powder used in this embodiment is not particularly limited. Preferred titanate compounds are those with a perovskite structure (MTiO ３ (M is one or more elements selected from the group consisting of Ba, Sr, Ca, and Mg). An example of a titanate compound used in this embodiment is barium titanate (BaTiO). ３ ) and strontium titanate (SrTiO ３ Examples include the following. One of these titanate compounds can be used alone. Alternatively, two or more titanate compounds may be used. 【0034】 Next, we will describe the cellulose nanofibers used in this embodiment. 【0035】 The cellulose nanofibers used in this embodiment can be extracted from wood by chemical treatment or mechanical treatment. This cellulose nanofiber is a fibrous substance with a nanometer size. In this embodiment, commercially available nanocellulose can be used. Examples of chemical treatment include treatments that change part of the cellulose structure. More specific examples include oxidation modification, phosphorylation modification, and carboxymethylation modification. 【0036】 As the cellulose nanofibers used in this embodiment, any modified type of cellulose nanofibers can be used. One type or two or more types of cellulose nanofibers may be used. Also, particularly in the case of MLCC applications, preferably, cellulose nanofibers with less residual carbon are used after firing at 1000 to 1500 °C. 【0037】 Examples of commercially available cellulose nanofibers include Cellifim L, C, UC (Morimachine Co., Ltd.), Rayocrysta 2SX, 2AX, and 2SXS (Daiichi Kogyo Seiyaku Co., Ltd.), Auro Visko (Oji Holdings Corporation), Selenia TC series (Nippon Paper Industries Co., Ltd.), MaCSIE (Ehime Paper Co., Ltd.), Stella Fine AX-140 and AX-160 (Maruizumi Paper Co., Ltd.), RCNF (Rengo Co., Ltd.), Aron Fibro T-OP100 (Toagosei Co., Ltd.), CNF aqueous dispersion SZ-37 (GenGen Chemical Industry Co., Ltd.), and CNF aqueous dispersion FUJI-MF (Marutomi Paper Co., Ltd.). 【0038】 The fiber diameter of the cellulose nanofibers used in this embodiment is preferably 500 nm or less, more preferably 300 nm or less. When the fiber diameter exceeds 500 nm, the dispersed particle diameter when dispersed in a solvent becomes large. As a result, good dispersion stability may not be obtained. The lower limit of the fiber diameter is not particularly limited. A preferable lower limit of the fiber diameter is about 2 nm. 【0039】 Next, a method for manufacturing the titanate compound fine particle powder according to this embodiment will be described. 【0040】The method for producing the titanate compound fine particle powder according to this embodiment includes a step of mixing an unmodified titanate compound powder and cellulose nanofibers, and a step of drying the obtained mixture. 【0041】 The method for producing the titanate compound fine particle dispersion according to this embodiment includes, in addition to the above step, a step of mixing the titanate compound fine particle powder, a polymer dispersant, and a solvent (mixing step). Preferably, the mixing step includes mixing a polymer dispersant. 【0042】 First, the method for producing the unmodified titanate compound powder used in this embodiment will be described. 【0043】 For the production of the unmodified titanate compound powder, either the reaction cake or the particle powder may be used. Preferably, the reaction cake obtained by hydrothermal synthesis is used. By using such a reaction cake, in the production process of the titanate compound fine particle powder described later, the surface of the titanate compound powder particles and the cellulose nanofibers can be more uniformly adhered or adsorbed to each other. Specifically, for example, referring to Patent No. 4702515 or Patent No. 6583637, such a reaction cake can be obtained according to these prior reports. 【0044】 The preferable range of the average primary particle diameter of the unmodified titanate compound powder is about 10 to 70 nm. The preferable range of its BET specific surface area is about 10 to 110 m ２ / g. 【0045】 The shape of the unmodified titanate compound powder particles is not particularly limited. In order to obtain excellent dispersibility, a shape as close to spherical as possible is preferable. 【0046】 When a cake is used as the unmodified titanate compound used in this embodiment, the suspension after washing with water can be used as it is. Alternatively, the concentration of the titanate compound in the suspension may be increased in advance by suction filtration or centrifugal filtration. The concentration of the titanate compound is not particularly limited as long as the fluidity of the suspension is maintained. 【0047】Next, the processing of cellulose nanofibers used in this embodiment will be described. 【0048】 The form of the cellulose nanofibers used in this embodiment is not particularly limited. A preferred form is an aqueous dispersion. 【0049】 In this embodiment, an unmodified titanate compound powder and cellulose nanofibers are mixed. The resulting mixture is then preferably stirred. Stirring may be performed while mixing. The stirring time is not particularly limited; a preferred stirring time is about 30 minutes. The temperature during stirring is preferably around room temperature. 【0050】 The stirring method is not particularly limited, as long as it causes the titanate compound powder particles and the cellulose nanofibers to adhere to or adsorb to each other. Preferably, the powder and cellulose nanofibers are mixed while crushing the titanate compound powder particles by mechanical force such as a bead mill or homogenizer. 【0051】 After the stirring described above, the solvent in the mixture is removed. The method of solvent removal (drying) is not particularly limited as long as it yields a dry powder. A preferred method is to use a vacuum dryer. In other words, any method of solvent removal (drying) is acceptable as long as drying yields a titanate compound powder with cellulose nanofibers attached. Examples of vacuum dryers include evaporators and vacuum stirring dryers. 【0052】 In this embodiment, the amount of cellulose nanofibers added depends on the particle size and BET specific surface area of ​​the unmodified titanate compound powder, as well as the size of the cellulose nanofibers. A preferred amount is 0.01 to 0.25% by weight, more preferably 0.02 to 0.24% by weight, and even more preferably 0.03 to 0.23% by weight, relative to the solid content of the unmodified titanate compound powder. 【0053】In this embodiment, the ratio of the amount of cellulose nanofiber added to the BET specific surface area of ​​the final product, the titanate compound fine particle powder, is given by (amount of cellulose nanofiber added (weight%) / BET specific surface area of ​​titanate compound fine particle powder (m²). ２ The ratio ( / g) is preferably greater than 0 and less than 0.003. If the ratio is outside this range, a dispersion with good dispersion stability may not be obtained. The ratio is more preferably 0.001 to 0.0028, and even more preferably 0.0012 to 0.0025. 【0054】 Next, the treatment of the polymer dispersant used in this embodiment will be described. 【0055】 A titanate compound powder dispersion according to this embodiment can be obtained by mixing the titanate compound fine particle powder obtained by the drying in the preceding step with a solvent. Preferably, the dispersion is prepared by mixing the titanate compound fine particle powder with a polymer dispersant and various solvents. 【0056】 In this embodiment, the amount of polymer dispersant added depends on the particle size of the titanate compound fine powder. The amount added is preferably 10% by weight or less, more preferably 9% by weight or less, and even more preferably 8% by weight or less. There is no particular lower limit to the amount of polymer dispersant added. The amount added is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 3% by weight or more. 【0057】 In this embodiment, the ratio of the total amount of cellulose nanofibers and polymer dispersant added to the BET specific surface area of ​​the titanate compound fine particle powder is ((Amount of cellulose nanofibers added (weight %) + Total amount of polymer dispersant added (weight %)) / BET specific surface area of ​​titanate compound fine particle powder (m²) ２ The ratio ( / g) is greater than 0, preferably 0.20 or less, more preferably 0.05 to 0.17, and even more preferably 0.07 to 0.15. If the ratio is outside the above range, the dispersion stability effect of the dispersion may not be obtained. 【0058】Next, we will describe the dispersion containing the titanate compound fine particle powder according to this embodiment (titanate compound powder dispersion). 【0059】 The titanate compound powder dispersion according to this embodiment comprises the titanate compound fine particle powder according to this embodiment and a solvent. Preferably, the dispersion further contains a polymeric dispersant. When the dispersion contains a polymeric dispersant, it exhibits low re-aggregation properties and excellent dispersion stability in various solvents. 【0060】 The titanate compound powder dispersion according to this embodiment contains fine titanate compound powder according to this embodiment. Therefore, a dispersion with dispersion stability can be obtained with a smaller amount of polymer dispersant. The titanate compound powder contained in the titanate compound powder dispersion according to this embodiment is fine. Nevertheless, the degree of particle aggregation in the dispersion solvent is very small. Therefore, the dispersion state of the dispersion can be kept stable. 【0061】 The titanate compound powder dispersion according to this embodiment preferably contains a polymeric dispersant. The content of the polymeric dispersant in the dispersion is preferably 10% by weight or less (excluding 0% by weight). Including 10% by weight or less of the polymeric dispersant provides stability of the dispersion over time. The amount of polymeric dispersant contained in the dispersion is more preferably 9% by weight or less, and even more preferably 8% by weight or less. If the amount of polymeric dispersant is 10% by weight or more, a high refractive index may not be obtained in optical applications. There is no particular lower limit to the content of the polymeric dispersant. The content of the polymeric dispersant is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 3% by weight or more. 【0062】 The acid value of the polymeric dispersant used in this embodiment is preferably 10 mg KOH / g or higher. If the acid value is less than 10 mg KOH / g, the dispersibility of the dispersion may be poor. Also, problems may arise with the stability of the dispersion over time. The acid value is preferably 15 mg KOH / g or higher, more preferably 20 mg KOH / g or higher. There is no particular upper limit to the acid value. The acid value of the polymeric dispersant is preferably 200 mg KOH / g or less, more preferably 150 mg KOH / g or less. 【0063】 The polymeric dispersant used in this embodiment is preferably anionic. The adsorption properties of nonionic or cationic polymeric dispersants to the surface of titanate compound powder particles may be inferior to those of anionic polymeric dispersants. 【0064】 The molecular weight of the polymer dispersant used in this embodiment is preferably about 800 to 2000. The molecular weight can be evaluated using GPC as previously reported. 【0065】 The preferred molecular structure of the polymer dispersant used in this embodiment is block-type or graft-type. The polymer dispersant exhibits excellent adsorption to the surface of titanate compound powder particles. As a result, the desorption of the polymer dispersant from the surface of the titanate compound powder particles is suppressed. This provides stability of the dispersion over time. 【0066】 The titanate compound fine particle powder according to this embodiment can be easily dispersed in a solvent. 【0067】 The solvent used in the titanate compound powder dispersion according to this embodiment is not particularly limited, but a solvent with an SP value of about 8 to 13 is preferred. Examples of preferred solvents include ethanol, DHT, PGMEA, DHTA, IPA, and toluene. One of these exemplified solvents can be used alone, or two or more solvents may be used in mixture form. 【0068】 The concentration of the titanate compound fine particle powder in the dispersion according to this embodiment is not particularly limited as long as it is dispersible. A preferred concentration is about 20 to 50% by weight. 【0069】 The method for dispersing the titanate compound fine particle powder according to this embodiment in various solvents is not particularly limited. For dispersion, for example, a stirrer, paint shaker, bead mill, or ball mill can be used. 【0070】 The distribution time is not particularly limited. A preferred distribution time is about one hour. 【0071】The dispersion according to this embodiment can be separated into solid and liquid components, for example, by centrifugation or standing. The average secondary particle diameter of the particles in the supernatant obtained is preferably 10 to 100 nm, more preferably 20 to 60 nm. If the average secondary particle diameter in the supernatant is within the above range, the dispersion exhibits excellent dispersibility and excellent dispersion stability over time. 【0072】 Furthermore, it is generally known that the smaller the value of the polydispersity index, which represents the particle size distribution of the particles, the smaller the variation in the average secondary particle diameter of those particles. The polydispersity index of the dispersion according to this embodiment is preferably 0.30 or less, more preferably 0.28 or less. 【0073】 In the modified titanate compound powder contained in the titanate compound fine particle powder according to this embodiment, cellulose nanofibers and titanate compound powder are strongly attached to or adsorbed. Therefore, aggregation of titanate compound fine particle powders during drying is suppressed. As a result, the titanate compound fine particle powder can be sufficiently dispersed in the solvent even with a small amount of dispersant. In addition, generally, in dispersions, the particle surface area increases due to the disintegration of the aggregated state of the particles. And with this increase in particle surface area, particle aggregation (re-aggregation) becomes more likely to occur. In the titanate compound powder dispersion according to this embodiment, by further adding a polymer dispersant, such aggregation (re-aggregation) becomes less likely to occur. As a result, it is presumed that the titanate compound powder dispersion according to this embodiment has good dispersibility and exhibits high dispersion stability. 【0074】 The titanate compound fine particle powder according to this embodiment may be any fine particle powder containing modified titanate compound powder. The fine particle powder may be a mixture of two or more powders. Furthermore, the fine particle powder may further contain unmodified titanate compound powder. 【0075】 Next, a resin composition containing titanate compound fine particle powder according to this embodiment (titanate compound powder resin composition) will be described. 【0076】The resin used in this embodiment is not particularly limited. Examples of resins that can be used include acrylic resin, polycarbonate resin, polystyrene resin, polyester resin, polyimide resin, AS resin, cyclic olefin resin, silicone resin, and fluororesin. Depending on the purpose or application, one of these exemplified resins can be used alone, or two or more resins can be used in mixture form. 【0077】 The concentration of the titanate compound fine particle powder, which is the solid content in the titanate compound powder resin composition according to this embodiment, is not particularly limited as long as it is dispersible in the resin. A preferred concentration is about 10 to 60% by weight. If the solid content in the resin composition is less than 10% by weight, productivity may be low in subsequent applications. If it exceeds 60% by weight, sufficient fluidity of the resin composition may not be obtained. 【0078】 This embodiment will be described in more detail by the following examples. However, this embodiment is not limited to these examples. 【0079】 Using photographs (magnification 50,000x) of unmodified titanate compound powder particles observed with a scanning electron microscope (Hitachi, Ltd. S-4300), the particle diameters of approximately 200 particles were measured. From the obtained measurement values, the average primary particle diameter was calculated. 【0080】 The average secondary particle diameter in each solvent was measured using dynamic light scattering ("FPAR-1000: Otsuka Electronics Co., Ltd."). More specifically, the average secondary particle diameter was calculated using cumulant analysis. Simultaneously, the polydispersity index was also calculated. The polydispersity index represents the particle size distribution obtained by histogram analysis. 【0081】 The specific surface area was measured using the BET method. 【0082】 The total carbon content was determined by evaluating the sample using the EMIA-920V2 carbon-sulfur analyzer (manufactured by Horiba, Ltd.). The obtained total carbon content was expressed as weight percent. 【0083】The polymer dispersant was quantified using a differential thermogravimetric simultaneous thermometry analyzer, "EXSTARTG / DTA (manufactured by SII)." Qualitative analysis was performed using an infrared spectrometer, "Nicolettis5FT-IR (manufactured by ThermoFisher Scientic)." 【0084】 The acid value of the polymer dispersant was measured using the AT-610 automatic potentiometric decompression device (manufactured by Kyoto Electronics Manufacturing Co., Ltd.). 【0085】 (Example 1) Referring to Japanese Patent Publication No. 4702515, an aqueous titanium chloride solution (manufactured by Kanto Chemical Co., Ltd.) was neutralized with barium hydroxide octahydrate (manufactured by Kanto Chemical Co., Ltd.). In this way, a titanium colloid was obtained. The obtained titanium colloid and the remaining barium hydroxide were stirred and mixed. In this way, barium titanate particles were produced at a reaction temperature of 70°C. After the hydrothermal reaction in the preceding step, the reaction mixture was cooled to room temperature. After washing with water and filtration, a barium titanate cake was obtained. 【0086】 By drying the cake obtained in the previous step at 110°C, unmodified barium titanate powder was obtained as an unmodified titanate compound powder without attached cellulose nanofibers. The average primary particle size of the obtained unmodified barium titanate powder was 25 nm. Its BET specific surface area was 48 m². ２ It was / g. 【0087】 To 1 kg of the barium titanate cake with a 40% solid content obtained in the previous step, 8 g of a 5% aqueous dispersion of Cellfim C100 (manufactured by Mori Machinery Co., Ltd.) as cellulose nanofiber was added. The resulting mixture was stirred and mixed at room temperature for 30 minutes. Subsequently, by vacuum drying, barium titanate fine particle powder containing modified barium titanate powder, which includes barium titanate powder and cellulose nanofibers that are attached to or adsorbed to each other, was obtained. 【0088】 The BET specific surface area of ​​the obtained barium titanate fine particle powder is 50 m². ２ The total carbon content was 0.21% by weight. 【0089】Furthermore, the barium titanate fine particle powder was observed using a scanning electron microscope (10,000x magnification). As a result, it was observed that the barium titanate powder and the cellulose nanofibers were adhering to or adsorbing to each other, with multiple barium titanate particles covering the surface of the cellulose nanofibers. 【0090】 Subsequently, 8 g of the barium titanate fine particle powder, 18.7 ml of DHTA as a solvent, and 5% by weight of HIPLAAD ED-403 (manufactured by Kusumoto Chemical Co., Ltd.) as a polymer dispersant were mixed. Then, 50 μm particle size ZrO ２ 40 g of beads were added. The resulting mixture was shaken using a paint shaker. This yielded a barium titanate powder dispersion. 【0091】 The dispersion obtained after shaking for two hours was subjected to solid-liquid separation using a centrifuge (5,000 rpm, 30 minutes). The particle size distribution was measured using the obtained supernatant. As indicators for evaluating dispersibility in various solvents, the average secondary particle size and polydispersity index after two hours of shaking are shown in Table 3. 【0092】 Furthermore, to evaluate dispersion stability, the re-aggregation characteristics of particles in the dispersion over time were assessed. The dispersions used for dispersibility evaluation were stored at room temperature for one month. The average secondary particle size and polydispersity index of the dispersions obtained thereafter are shown in Table 3. 【0093】 (Examples 2-4, Comparative Example 1) Following the same procedure as in Example 1, barium titanate fine particle powder containing modified barium titanate powder was obtained under various modified conditions, as shown in Table 1. The properties of the obtained barium titanate fine particle powder are shown in Table 1. 【0094】 【0095】 【0096】 Furthermore, using the same procedure as in Example 1, barium titanate powder dispersions containing barium titanate fine particle powder were obtained with various modified types and contents of polymer dispersants, as shown in Table 2. 【0097】 【0098】 Each of the barium titanate fine particle powders obtained in Examples 2 to 4 was observed using a scanning electron microscope. As a result, it was observed that the barium titanate powder and the cellulose nanofibers were attached to or adsorbed to each other, with multiple barium titanate particles covering the surface of the cellulose nanofibers. 【0099】 In the barium titanate powder dispersions containing the barium titanate fine particle powder obtained in Examples 1 to 4, the particles were sufficiently dispersed in the solvent even with a small amount of polymer dispersant of 10% by weight or less. The good dispersibility of the dispersion was confirmed. Furthermore, by comparison, it was found that the average secondary particle size and polydispersity index of the dispersion after standing for one month were equivalent to the average secondary particle size and polydispersity index before standing. It was also confirmed that the dispersion according to this embodiment exhibits excellent dispersion stability over time. 【0100】 (Comparative Example 2) 20 g of barium titanate cake with a 40% solid concentration obtained in Example 1, 18.7 ml of DHTA as a solvent, 0.16 g of Cellfim C100 (manufactured by Mori Machinery Co., Ltd.) as cellulose nanofibers, 5% by weight of HIPLAAD ED-403 (manufactured by Kusumoto Chemical Co., Ltd.) as a polymer dispersant, and ZrO with a particle size of 50 μm ２ 40 g of beads were mixed in. The resulting mixture was shaken for 2 hours using a paint shaker. This yielded a barium titanium oxide powder dispersion containing unmodified barium titanate powder. 【0101】 The average secondary particle size, as determined by measurement from the titanate compound powder dispersions obtained in Comparative Example 1 and Comparative Example 2, was remarkably large. Particle aggregation was observed in these dispersions. Furthermore, some precipitation occurred in these dispersions. It was confirmed that the dispersibility of the dispersions was insufficient. 【0102】In Comparative Example 2, the mixture obtained after mixing unmodified barium titanate powder and cellulose nanofibers was not dried. Therefore, barium titanate fine particle powder containing barium titanate powder with cellulose nanofibers attached (modified barium titanate powder) was not obtained. Furthermore, the ratio of total carbon content to BET specific surface area was also very large. 【0103】 (Comparative Example 3) Unmodified barium titanate powder was obtained by drying the 40% solid concentration barium titanate cake obtained in Example 1 at 110°C. Using this barium titanate powder, a cellulose nanofiber-free barium titanate powder dispersion was obtained using the same procedure as in Example 1, with various modified polymer dispersants and solvents as shown in Table 2. 【0104】 The dispersibility of the dispersion in various solvents was evaluated using the same procedure as in Example 1. Similarly, the re-aggregation characteristics over time were evaluated as an assessment of the dispersion stability. The evaluation results are shown in Table 3. 【0105】 The dispersion obtained in Comparative Example 3 contained a large amount of polymer dispersion, 10% by weight. Therefore, the dispersibility after shaking for 2 hours was good. On the other hand, after the dispersion was left to stand for 1 month, a precipitate was observed in the dispersion. The dispersion's stability over time was not observed. 【0106】 The titanate compound fine particle powder according to this embodiment, when mixed with a solvent and shaken, formed a dispersion containing fine particles and exhibiting an excellent particle size distribution in terms of average secondary particle diameter. Furthermore, comparative analysis showed that the average secondary particle diameter and polydispersity index of the dispersion after 2 hours of shaking remained virtually unchanged from those of the dispersion after 1 hour of shaking. No changes in these average secondary particle diameters and polydispersity index over time were observed. 【0107】Therefore, using the titanate compound fine particle powder according to this embodiment, a titanate compound powder dispersion with sufficient dispersibility can be prepared in a relatively short time. Furthermore, this dispersion exhibits low re-aggregation properties. In other words, this dispersion is recognized to have excellent dispersion stability over time. 【0108】 In the modified titanate compound powder contained in the titanate compound fine particle powder according to this embodiment, the titanate compound particles adhere to cellulose nanofibers. This suppresses interparticle aggregation. Furthermore, the titanate compound fine particle powder according to this embodiment can be dispersed in various solvents with a small amount of dispersant. Moreover, the re-aggregation tendency of the obtained dispersion is low. As a result, a titanate compound powder dispersion with excellent dispersion stability can be obtained. Therefore, the titanate compound fine particle powder according to this embodiment is suitable, for example, as a material for MLCC applications, an anti-reflective coating, and a material with high transparency and high refractive index required for lenses. 【0109】 This international application claims priority based on Japanese Patent Application No. 2024-216315, filed on 11 December 2024, and the entire contents of said Japanese Patent Application No. 2024-216315 are incorporated herein by reference. 【0110】 The above description of specific embodiments of the present invention is provided for illustrative purposes only. It is not intended to be exhaustive or to limit the invention to the forms described. Numerous modifications and changes are possible in light of the above description, as will be obvious to those skilled in the art.

Claims

1. A titanate compound fine particle powder comprising a modified titanate compound powder, wherein the modified titanate compound powder comprises cellulose nanofibers and the titanate compound powder, the cellulose nanofibers and the titanate compound are attached to or adsorbed to each other, and the ratio of the total carbon content of the titanate compound fine particle powder to the BET specific surface area of ​​the titanate compound fine particle powder is 0.006 or less.

2. A titanate compound powder dispersion comprising the titanate compound fine particle powder described in claim 1 and a solvent.

3. The titanate compound powder dispersion according to claim 2, further comprising a polymer dispersant.

4. A titanate compound powder resin composition comprising the titanate compound fine particle powder and resin described in claim 1.

5. A method for producing a titanate compound fine particle powder, comprising: mixing an unmodified titanate compound powder with cellulose nanofibers; drying the mixture of the unmodified titanate compound powder and the cellulose nanofibers; and causing the cellulose nanofibers and the unmodified titanate compound powder in the mixture to adhere to or adsorb to each other.

6. A method for producing a titanate compound powder dispersion, comprising mixing the titanate compound fine particle powder obtained by the method of claim 5 with a polymer dispersant and a solvent.

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