Amine compound stable type zirconium modified niobic acid dispersion liquid

Abstract

To develop a novel niobic acid dispersion liquid capable of applying to catalyst materials and battery materials.SOLUTION: This is a dispersion liquid containing dispersed particles that include core particles and modifiers that modify the surface of the core particles, where the core particles contain niobic acid, and the modifiers contain zirconium components, and it includes amine compounds as a dispersion stabilizer, known as an amine compound stabilized zirconium modified niobic acid dispersion liquid. The amine compound stabilized zirconium modified niobic acid dispersion liquid can be produced through a process that includes (1) a first step of mixing a niobic acid sol with a zirconium compound at pH 7 or higher, (2) a second step of adding an amine compound, and (3) a third step of heating.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a zirconium modified niobic acid dispersion stabilized with an amine compound. [Background technology]

[0002] Niobium oxide is used as a catalyst material taking advantage of its solid acidity. In recent years, niobium-based sol has been attracting attention as a surface coating material for positive and negative electrodes in the field of battery materials.

[0003] The applicant first invented a technology relating to ammonium niobate sol as a niobic acid sol, as described in Patent Document 1, and then invented an amine compound-stabilized niobic acid sol and an amine compound / organic acid-stabilized niobic acid sol as described in Patent Document 2, and an alkali metal-stabilized niobic acid sol as described in Patent Document 3, and further invented a lithium-phosphate-stabilized niobic acid sol as described in Patent Document 4. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5441264 [Patent Document 2] Patent No. 6156876 [Patent Document 3] Patent No. 6774158 [Patent Document 4] Patent No. 7161276 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to develop a new niobic acid dispersion liquid that can be applied to catalyst materials, battery materials, and the like. [Means for solving the problem]

[0006] As a result of intensive research aimed at discovering new possibilities for niobic acid dispersions, the inventors came up with the idea of ​​modifying the surfaces of dispersed particles of niobic acid sol with zirconium, which is used in a variety of applications such as catalysts, battery materials, and optical materials, and developed a zirconium-modified niobic acid sol. The zirconium-modified niobic acid sol is a sol in which dispersed particles containing core particles and a modifier that modifies the surface of the core particles are dispersed, the core particles contain niobic acid, the modifier contains a zirconium component, and ZrO2 / Nb2O5 (molar ratio) is in the range of 0.01 to 0.15. The zirconium-modified niobic acid sol can be produced by a process including (1) a first step of mixing a niobic acid sol having a pH of 7 or more with a zirconium compound, and (2) a second step of heating. However, the zirconium-modified niobic acid sol is limited in the amount of zirconium that can be modified, and the molar ratio of ZrO2 / Nb2O5 must be 0.15 or less as described above. As a result of further intensive research into zirconium-modified niobic acid sol that can be modified with a larger amount of zirconium components, it was found that using an amine compound as a dispersion stabilizer is effective, and the present invention was completed based on this knowledge.

[0007] The present invention is as follows. [1] A dispersion liquid in which dispersed particles containing core particles and a modifier that modifies the surface of the core particles are dispersed, the core particles containing niobic acid, the modifier containing a zirconium component, and an amine compound as a dispersion stabilizer, the amine compound-stabilized zirconium-modified niobic acid dispersion liquid. [2] A method for producing the amine compound-stabilized zirconium-modified niobic acid dispersion according to [1] above, comprising the following steps: (1) A first step of mixing a niobic acid sol having a pH of 7 or more with a zirconium compound (2) The second step of adding an amine compound (3) The third step is heating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described in detail below based on preferred embodiments, but the present invention is not limited to the following embodiments and various modifications are possible within the scope of the claims. In addition, in the present invention, the expression "numeric value 1 to numerical value 2" regarding a numerical range means a numerical range including both the numerical values ​​1 and 2, with numerical value 1 being the lower limit and numerical value 2 being the upper limit, and is synonymous with "numerical value 1 or more and numerical value 2 or less."

[0009] The present invention relates to an amine compound-stabilized zirconium-modified niobic acid dispersion (hereinafter referred to as the "dispersion of the present invention"), which is a dispersion in which dispersed particles containing core particles and a modifier that modifies the surface of the core particles are dispersed, the core particles containing niobic acid, the modifier containing a zirconium component, and containing an amine compound as a dispersion stabilizer.

[0010] The core particles include niobic acid. A good example of the core particles is a dispersed particle in an ammonium niobate sol described in Patent Document 1, and the dispersed particle is composed of amorphous ammonium niobate. Another good example of the core particles is a dispersed particle in an amine compound stabilized niobic acid sol described in Patent Document 2, and the dispersed particle is a particle in which the ammonia content in amorphous ammonium niobate is reduced and the dispersion is stabilized by an amine compound instead of ammonia. Another good example of the core particles is a dispersed particle in an amine compound / organic acid stabilized niobic acid sol described in Patent Document 2, and the dispersed particle is a particle in which the ammonia content in amorphous ammonium niobate is reduced and the dispersion is stabilized by an amine compound and an organic acid instead of ammonia. Another good example of the core particles is a dispersed particle in an alkali metal stabilized niobic acid sol described in Patent Document 3, and the dispersed particle has the following two patterns (a) and (b). In the case of (a), it is a {complex of niobic acid and an alkali metal}, and in the case of (b), it is a {complex of niobic acid and ammonia} in addition to a {complex of niobic acid and an alkali metal}. Furthermore, the core particles may be composed of two or more types of dispersed particles among the preferred examples given above.

[0011] The modification contains a zirconium component. The modification may contain a subcomponent other than the zirconium component. Examples of the subcomponent include ammonia and alkali metals. Examples of the alkali metal include lithium, sodium, and potassium.

[0012] The dispersed particles include the above-mentioned core particles and a modifier that modifies the surface of the core particles, and the dispersed particles have the properties of a dispersion liquid due to their dispersed state. This dispersed state is brought about by an amine compound that is a dispersion stabilizer. Note that the amine compound as a dispersion stabilizer acts to stabilize the dispersed particles, and is therefore different from the amine compound that acts on the core particles when the core particles are dispersed particles in an amine compound-stabilized niobic acid sol or an amine compound / organic acid-stabilized niobic acid sol described in Patent Document 2.

[0013] The particle size of the dispersed particles is not particularly limited as long as the properties of the dispersion liquid are obtained, but for example, the average particle size of the dispersed particles is preferably within the range of 5 to 4000 nm. The upper limit of the above range is more preferably 3500 nm, and even more preferably 3200 nm. Here, the average particle size of the dispersed particles refers to the median size when the dispersion liquid of the present invention is measured using a dynamic light scattering particle size distribution measuring device "LB-500" manufactured by Horiba, Ltd.

[0014] A preferred characteristic of the dispersion of the present invention is that it has a viscosity of 100 mPa·s or less when the liquid temperature is set at 25°C. This viscosity characteristic can be said to be useful, for example, in applications in which the dispersion of the present invention is applied. It is more preferred that the viscosity is 50 mPa·s or less. The viscosity here is measured using the dispersion of the present invention with an E-type viscometer "TVE-25L" (rotor: 1°34' x R24) manufactured by Toki Sangyo Co., Ltd.

[0015] The content of the amine compound as a dispersion stabilizer is not particularly limited as long as the amount is sufficient to obtain stabilization as a dispersion liquid. For example, the amine compound / ZrO2 (molar ratio) is preferably in the range of 1.0 to 30.0. The lower limit of the above range is more preferably 1.2, and even more preferably 1.5. The upper limit of the above range is more preferably 25.0, and even more preferably 20.0. Therefore, more preferred ranges of the amine compound / ZrO2 (molar ratio) include 1.0 to 25.0, 1.0 to 20.0, 1.2 to 30.0, 1.2 to 25.0, 1.2 to 20.0, 1.5 to 30.0, 1.5 to 25.0, and 1.5 to 20.0.

[0016] A preferred example of the amine compound as a dispersion stabilizer is quaternary ammonium hydroxide. Examples of quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldiethylammonium hydroxide, choline, etc. Only one type of amine compound may be used, or multiple types may be used.

[0017] The ZrO2 / Nb2O5 (molar ratio) in the dispersion of the present invention is preferably in the range of, for example, 0.05 to 2.0. In this range, the dispersion is easily stabilized in the presence of an amine compound as a dispersion stabilizer. In the region where the molar ratio is close to 0.05, it is presumed that niobic acid accounts for the majority, with a modification containing a zirconium component being present in part. The upper limit of the range is more preferably 1.8.

[0018] The Nb2O5 concentration in the dispersion of the present invention is preferably, for example, in the range of 1 to 30 mass%. The lower limit of the concentration is more preferably 3 mass% from the economical viewpoint of production and transportation. The upper limit of 30 mass% is set from the viewpoint of avoiding deterioration of handling due to high viscosity. In consideration of convenience in production and use, the upper limit is more preferably 25 mass%.

[0019] A preferred method for preparing the dispersion of the present invention comprises the following steps. (1) A first step of mixing a niobic acid sol having a pH of 7 or more with a zirconium compound (2) The second step of adding an amine compound (3) The third step is heating.

[0020] The niobic acid sol having a pH of 7 or more is not particularly limited as long as the sol has a pH of 7 or more, and examples thereof include the ammonium niobate sol described in Patent Document 1, the amine compound-stabilized niobic acid sol and the amine compound / organic acid-stabilized niobic acid sol described in Patent Document 2, and the alkali metal-stabilized niobic acid sol described in Patent Document 3. Examples of commercially available products include "Bailar Nb-G6000" manufactured by Taki Chemical Industry Co., Ltd. as an ammonium niobate sol, "Bailar Nb-G6600" manufactured by the same company as an amine compound / organic acid-stabilized niobic acid sol, and "Bailar Nb-G6700" manufactured by the same company as an alkali metal-stabilized niobic acid sol. Only one type of niobic acid sol may be used, or multiple types may be used.

[0021] The zirconium compound is not particularly limited, and may be any of zirconium salts that dissolve in water and exhibit alkalinity (water-soluble alkaline zirconium salts), zirconium salts that dissolve in water and exhibit neutrality (water-soluble neutral zirconium salts), and zirconium salts that dissolve in water and exhibit acidity (water-soluble acidic zirconium salts). As the form of the zirconium salt, sulfate, nitrate, carbonate, ammonium salt, acetate, oxy salt, etc. are preferable. Specific examples include zirconium sulfate, zirconium nitrate, zirconium carbonate, potassium zirconium carbonate, zirconium acetate, ammonium zirconium carbonate, zirconium oxychloride, zirconium oxynitrate, zirconium oxyacetate, etc. The zirconium compound may be used alone or in combination.

[0022] A mixed solution is obtained by mixing a niobic acid sol having a pH of 7 or more with a zirconium compound. There is no particular restriction on the mixing method, and mixing may be performed by a conventional method. For example, a zirconium compound is added to a niobic acid sol under stirring. The zirconium compound may be liquid or solid, but it is particularly preferable to use a liquid. When using a solid, it is particularly preferable to use a powder, and it may be dispersed in a small amount of water. There is no particular restriction on the preparation method of the mixed solution, but preferably, the niobic acid sol is made into an aqueous solution of 0.1 to 5.0 mass% as Nb2O5, and this is mixed with a zirconium compound to obtain a mixed solution exhibiting a sol-like state. In this case, if a liquid zirconium compound is used, it is preferable that the ZrO2 concentration is in the range of 0.1 to 5.0 mass%. In particular, when a water-soluble acidic zirconium salt is used, if neutralization is not sufficiently performed in mixing with a niobic acid sol having a pH of 7 or more, an alkali may be added to the niobic acid sol having a pH of 7 or more before mixing with the water-soluble acidic zirconium salt. Examples of the alkali include ammonia and hydroxides of alkali metals.

[0023] When the mixture gels, it is preferable to carry out a washing step as an optional step. Gelation is particularly likely to occur when a water-soluble acidic zirconium salt is used. There is no particular restriction on the washing method, and ultrafiltration while adding water is preferred. The end point of washing can be determined when the filtrate EC is 0.2 to 2 mS / cm. If desalting can be achieved by washing, dispersion can be achieved by heating in the third step. Ultrafiltration is a washing method that is convenient for desalting.

[0024] In the second step, an amine compound is added to the mixed liquid obtained in the first step or the washed matter obtained in the optional washing step. Preferably, the amine compound is added to the mixed liquid or the washed matter under stirring.

[0025] In the third step, the amine compound-containing mixed solution or the amine compound-containing washed product obtained in the second step is heated. The heating is not particularly limited as long as a dispersion liquid is obtained, and for example, the heating temperature is preferably in the range of 90 to 200°C. The lower limit of the above range is more preferably 100°C, and the upper limit is more preferably 150°C. Thus, more preferred heating temperature ranges include 90 to 150°C, 100 to 200°C, and 100 to 150°C. The heating time may be appropriately adjusted depending on the heating temperature, and is preferably in the range of, for example, 1 to 8 hours.

[0026] After the third step, any step, such as a washing step or a concentration adjustment step, may be carried out.

[0027] Although the mechanism by which the surface of the core particles is modified by the modifier is not clear, it is assumed that the modifier is present in a state of being bound or adsorbed to the surface of the core particles. In terms of the zirconium component, it is assumed that the zirconium component derived from the zirconium compound neutralized or hydrolyzed by the niobic acid on the surface of the core particles by heating in the third step is bound or adsorbed. The form of the zirconium component as a compound is thought to be zirconium oxide or zirconium hydroxide.

[0028] The dispersion of the present invention can be suitably used for various applications, such as additives for catalysts, secondary batteries, electronic materials, and coating additives. EXAMPLES

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0030] (raw materials) The ammonium niobate sol used was "Baylal Nb-G6000" (Nb2O5 concentration: 6 mass%, pH 8) manufactured by Taki Chemical Co., Ltd. The amine compound / organic acid stabilized niobate sol used was "Baylal Nb-G6600" (Nb2O5 concentration: 6 mass%, pH 8) manufactured by the same company, and the alkali metal stabilized niobate sol used was "Baylal Nb-G6700" (Nb2O5 concentration: 6 mass%, pH 8) manufactured by the same company.

[0031] Example 1 1110g of ammonium niobate sol was diluted to 1.0 mass% as Nb2O5 by adding 5550g of ion-exchanged water. A solution prepared by adding 326g of ion-exchanged water to 17g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was subjected to ultrafiltration washing until the filtrate EC was 0.3mS / cm, and a washed product was obtained (Nb2O5 concentration: 11.0 mass%, pH 7.7). 165g of 35% tetraethylammonium hydroxide (hereinafter abbreviated as "TEAH") aqueous solution (molar ratio of TEAH / ZrO2 = 17.1) was added to 500g of this washed product and stirred well, and then heated at 100 ° C for 3 hours to obtain an amine compound-stabilized zirconium-modified niobic acid dispersion of Example 1A. The resulting solution was concentrated using an evaporator to obtain an amine compound-stabilized zirconium-modified niobic acid dispersion of Example 1 B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 1A and 1B was 0.11.

[0032] Example 2 1045g of ammonium niobate sol was diluted to 1.0 mass% as Nb2O5 by adding 5227g of ion-exchanged water. A solution prepared by adding 691g of ion-exchanged water to 36g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.2mS / cm, and a washed product was obtained (Nb2O5 concentration: 7.7 mass%, pH 6.9). 126g of 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 8.3) was added to 500g of this washed product and stirred well, and then heated at 120 ° C for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 2A. This was concentrated using an evaporator to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 2B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 2A and 2B was 0.24.

[0033] Example 3 4868g of ion-exchanged water was added to 974g of ammonium niobate sol to dilute it to 1.0% by mass as Nb2O5. A solution prepared by adding 1102g of ion-exchanged water to 58g of an aqueous zirconium oxychloride solution (ZrO2 concentration: 20% by mass) to prepare 1.0% by mass as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.3mS / cm, and a washed product was obtained (Nb2O5 concentration: 3.8% by mass, pH 7.0). 54g of a 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 4.2) was added to 500g of this washed product and stirred well, and then heated at 140 ° C for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 3A. This was concentrated using an evaporator to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 3B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 3A and 3B was 0.41.

[0034] Example 4 797 g of ammonium niobate sol was diluted to 1.0 mass% as Nb2O5 by adding 12 g of 25% ammonia water and 3987 g of ion-exchanged water. A solution prepared by adding 2107 g of ion-exchanged water to 111 g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was subjected to ultrafiltration washing until the filtrate EC was 0.3 mS / cm, and a washed product was obtained (Nb2O5 concentration: 2.0 mass%, pH 4.7). 24 g of 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 1.5) was added to 500 g of this washed product and stirred well, and then heated at 140 ° C. for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 4A. This was concentrated using an evaporator to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 4B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 4A and 4B was 1.0.

[0035] Example 5 22g of 25% ammonia water and 3441g of ion-exchanged water were added to 688g of ammonium niobate sol to dilute it to 1.0% by mass as Nb2O5. A solution prepared by adding 2727g of ion-exchanged water to 144g of an aqueous zirconium oxychloride solution (ZrO2 concentration: 20% by mass) to prepare 1.0% by mass as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.4mS / cm, and a washed product was obtained (Nb2O5 concentration: 2.0% by mass, pH 4.1). 43g of a 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 1.8) was added to 500g of this washed product and stirred well, and then heated at 130 ° C for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 5A. This was concentrated using an ultrafiltration device to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 5B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 5A and 5B was 1.4.

[0036] Example 6 4868g of ion-exchanged water was added to 974g of amine compound-organic acid stabilized niobic acid sol to dilute it to 1.0 mass% as Nb2O5. A solution prepared by adding 1102g of ion-exchanged water to 58g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.3mS / cm to obtain a washed product (Nb2O5 concentration: 4.4 mass%, pH 4.7). 74g of 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 5.0) was added to 500g of this washed product, stirred well, and then heated at 140 ° C for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 6A. This was concentrated using an evaporator to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 6B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 6A and 6B was 0.41.

[0037] Example 7 4868g of ion-exchanged water was added to 974g of alkali metal stabilized niobic acid sol to dilute it to 1.0% by mass as Nb2O5. A solution prepared by adding 1102g of ion-exchanged water to 58g of an aqueous zirconium oxychloride solution (ZrO2 concentration: 20% by mass) to prepare 1.0% by mass as ZrO2 was added to this solution under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.4mS / cm, and a washed product was obtained (Nb2O5 concentration: 4.8% by mass, pH 5.8). 81g of a 35% TEAH aqueous solution (molar ratio of TEAH / ZrO2 = 5.0) was added to 500g of this washed product, and after stirring well, it was heated at 140 ° C for 3 hours to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 7A. This was concentrated using an evaporator to obtain an amine compound stabilized zirconium modified niobic acid dispersion of Example 7B. The molar ratio of ZrO2 / Nb2O5 in the amine compound-stabilized zirconium-modified niobic acid dispersions of Examples 7A and 7B was 0.41.

[0038] Comparative Example 1 In Example 2, 35% TEAH aqueous solution was not added. That is, 5227g of ion-exchanged water was added to 1045g of ammonium niobate sol to dilute it to 1.0 mass% as Nb2O5. A solution prepared by adding 691g of ion-exchanged water to 36g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was washed by ultrafiltration until the filtrate EC was 0.2mS / cm, and the washed product was heated at 120°C for 3 hours, but the liquid became cloudy and the generation of precipitates was also observed, and no dispersion was obtained.

[0039] Comparative Example 2 In Example 5, 35% TEAH aqueous solution was not added. That is, 22g of 25% ammonia water and 3441g of ion-exchanged water were added to 688g of ammonium niobate sol to dilute it to 1.0 mass% as Nb2O5. A solution prepared by adding 2727g of ion-exchanged water to 144g of zirconium oxychloride aqueous solution (ZrO2 concentration: 20 mass%) to prepare 1.0 mass% as ZrO2 was added to this liquid under stirring to obtain a gelled mixture. This was subjected to ultrafiltration washing until the filtrate EC was 0.4mS / cm, and a washed product was obtained (Nb2O5 concentration: 2.0 mass%, pH 4.1). This washed product was heated at 130°C for 3 hours, but the liquid became cloudy, the generation of precipitates was also observed, and no dispersion was obtained.

[0040] [Reference example 1] To 1,000 g of ammonium niobate sol under stirring, 15.4 g of an aqueous solution of ammonium zirconium carbonate (ZrO2 concentration: 20% by mass) was added, and then heated at 100°C for 2 hours to obtain a zirconium-modified niobate sol of Reference Example 1 having a ZrO2 / Nb2O5 (molar ratio) of 0.11 and an Nb2O5 concentration of 5.9% by mass.

[0041] [Reference example 2] To 1,000 g of ammonium niobate sol under stirring, 7.7 g of an aqueous solution of potassium zirconium carbonate (ZrO2 concentration: 19 mass%) was added, and then heated at 100°C for 2 hours to obtain a zirconium-modified niobate sol of Reference Example 2 having a ZrO2 / Nb2O5 (molar ratio) of 0.05 and an Nb2O5 concentration of 5.8 mass%.

[0042] [Reference example 3] To 1,000 g of ammonium niobate sol under stirring, 21.9 g of an aqueous solution of potassium zirconium carbonate (ZrO2 concentration: 19% by mass) was added, and the mixture was heated at 100°C for 2 hours. Ion-exchanged water was then added to obtain a zirconium-modified niobic acid sol of Reference Example 3 having a ZrO2 / Nb2O5 (molar ratio) of 0.15 and an Nb2O5 concentration of 3.1% by mass.

[0043] (Analysis method) The amine compound-stabilized zirconium-modified niobic acid dispersions obtained in Examples 1 to 7 were subjected to the following analyses in their as-is form. pH: Measured using a Horiba pH meter "D-53." ·EC: Measured using an EC meter "CM42-X" manufactured by DKK-TOA Corporation. Haze and total light transmittance: Measured using a haze meter "COH7700" manufactured by Nippon Denshoku Industries Co., Ltd., at wavelengths of 400 to 700 nm (10 nm intervals) and an optical path length of 10 mm. Viscosity: The liquid temperature was set to 25°C and measurements were taken using a Toki Sangyo Co., Ltd. E-type viscometer "TVE-25L" (rotor: 1°34' x R24).

[0044] The results are shown in Table 1.

[0045] [Table 1]

Claims

1. A dispersion liquid in which dispersed particles including core particles and a modifying substance that modifies the surface of the core particles are dispersed, the core particles contain niobic acid; the modification comprises a zirconium component; Contains an amine compound as a dispersion stabilizer, Amine compound stabilized zirconium modified niobic acid dispersion.

2. A method for producing the amine compound-stabilized zirconium-modified niobic acid dispersion according to claim 1, comprising the steps of: (1) A first step of mixing a niobic acid sol having a pH of 7 or more with a zirconium compound (2) The second step of adding an amine compound (3) The third step is heating.

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