Zirconium phosphate and slurry

Abstract

A zirconium phosphate that is represented by M1Zr2(M2PO4)a(PO4)b·nH2O (in which M1 and M2 are a monovalent cation and may be the same or different, a and b are numbers that satisfy 0.3<a≤1.8, 3.1≤(a+b)≤3.6, and 2a+3b=9, and n is a number that satisfies 0≤n≤2).

Description

Technical Field

[0001] The present invention relates to zirconium phosphate and a slurry.

Background Art

[0002] Conventionally, as zirconium phosphate, there is MZr having a structure containing 3 phosphorus atoms 2 (PO 4 ) 3 . Also, conventionally, as zirconium phosphate, there are those having a structure containing 2 phosphorus atoms (for example, MZrH(PO 4 ) 2 ).

[0003] As methods for producing zirconium phosphate, there are a solid-phase method (firing method) and a wet method. In the solid-phase method, the particle size of zirconium phosphate becomes coarse, and as a result, the specific surface area becomes low, making it difficult to form a slurry. Examples of patent documents disclosing the wet method include Patent Documents 1 to 4.

[0004] Patent Document 1 discloses A x NH 4(1-x) Zr 2 (PO 4 ) 3 ·nH 2 O (where A represents an alkali metal ion, X is a number satisfying 0 < X < 1, and n is a number satisfying 0 ≤ n ≤ 2).

[0005] Patent Document 2 discloses AZr 2 (PO 4 ) 3 ·nH 2 O (where A represents at least one of an ammonium ion or an alkali metal ion, and n is a number satisfying 0 ≤ n ≤ 2).

[0006] Patent Document 3 discloses HnR 1-n Zr 2 (PO 4 ) 3 ·mH 2 O (where R is NH4 or an amine cation, where 0 ≦ n ≦ 1 and 0 ≦ m ≦ 2) is disclosed.

[0007] Patent Document 4 discloses, as zirconium phosphate, M a Zr b (PO 4 ) 3 ·nH 2 O (where M is at least one ion selected from alkali metal ions, hydrogen ions, and oxonium ions, a and b are numbers satisfying 1.75 < b < 2 and a + 4b = 9, and n is 2 or less) is disclosed.

[0008] Although the zirconium phosphate of Patent Document 4 has b less than 2, since a + 4b = 9, a becomes a number greater than 1. The reason a becomes a number greater than 1 is that, with the number of Zr made less than 2, the number of M, which is a monovalent cation, is increased to adjust the charge, but the number of phosphorus atoms, which are anions, is fixed at 3.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] As described above, zirconium phosphate in which the number of phosphorus atoms is greater than 3 and less than 4 has not been conventionally known. That is, zirconium phosphate containing phosphorus atoms at a ratio of 3.1 to 3.6 atoms with respect to 2 atoms (equivalent) of zirconium is not known.

[0011] An object of the present invention is to provide zirconium phosphate containing phosphorus atoms in a ratio of 3.1 to 3.6 atoms relative to 2 atoms (equivalent) of zirconium. Another object of the present invention is to provide a slurry in which the zirconium phosphate is dispersed in an aqueous solvent.

Means for Solving the Problems

[0012] The inventors of the present invention have conducted intensive studies on zirconium phosphate. As a result, they have succeeded in creating zirconium phosphate containing phosphorus atoms in a ratio of 3.1 to 3.6 atoms relative to 2 atoms (equivalent) of zirconium, and have completed the present invention.

[0013] That is, the zirconium phosphate according to the present invention is characterized by being represented by the following formula [1]. M1Zr 2 (M2PO 4 ) a (PO 4 ) b ·nH 2 O [1] However, in formula [1], M1 and M2 are monovalent cations, which may be the same or different from each other, a and b are numbers satisfying 0.3 < a ≦ 1.8, 3.1 ≦ (a + b) ≦ 3.6, and 2a + 3b = 9, and n is a number satisfying 0 ≦ n ≦ 2.

[0014] According to the above configuration, in formula [1], (a + b) is 3.1 or more and 3.6 or less, and the phosphorus atoms are contained in a ratio of 3.1 to 3.6 atoms relative to 2 atoms of zirconium. Such zirconium phosphate is a novel zirconium phosphate not known in the past.

[0015] In the above configuration, the crystal structure includes rhombohedral crystals, and the proportion of the rhombohedral crystals is preferably more than 90% with respect to the whole zirconium phosphate.

[0016] When the zirconium phosphate contains rhombohedral crystals as a crystal structure and the ratio of the rhombohedral crystals to the entire zirconium phosphate is greater than 90%, it is easy to obtain a zirconium phosphate powder having a fine particle size and a relatively uniform particle size, as is evident from the examples.

[0017] Here, when the ratio of phosphorus atoms to two zirconium atoms is greater than 3.6, the crystal structure will contain a large amount of monoclinic crystals, and it is difficult to make the proportion of rhombohedral crystals greater than 90% of the entire zirconium phosphate. On the other hand, according to the above-mentioned configuration, even though the crystal structure contains a large amount of rhombohedral crystals, the content of phosphorus atoms can be made larger than that of the conventional method. A large content of phosphorus atoms means that the amount of phosphate ions (PO 4 3- ) and hydrogen phosphate ion (HPO 4 2- ) content. And phosphate ion (PO 4 3- ) and hydrogen phosphate ion (HPO 4 2- ) has a high affinity for water, so phosphate ions (PO 4 3- ) and hydrogen phosphate ion (HPO 4 2- Zirconium phosphate with a high content of ) has improved dispersibility in aqueous solvents.

[0018] In this way, according to the above-mentioned configuration, since the rhombohedral crystals are contained at more than 90% and the number of phosphorus atoms is 3.1 or more, the particle size can be made fine and the dispersibility in the aqueous solvent can be improved. As a result, even if dispersed in the aqueous solvent at a high concentration, the particles are unlikely to aggregate.

[0019] In the above configuration, the particle diameter D 90 It is preferable that the thickness is 1.5 μm or less.

[0020] Particle size D 90 When the particle size is 1.5 μm or less, zirconium phosphate having a fine particle size can be provided. Generally, the finer the particle size of a particle (powder), the more easily it aggregates, and the lower the dispersibility in a solvent. On the other hand, according to the above-mentioned configuration, the number of phosphorus atoms is 3.1 or more, and the affinity with water is high, so that the particle diameter D 90 Even if the particles are as fine as 1.5 μm or less, it is possible to provide zirconium phosphate that is highly dispersible in aqueous solvents.

[0021] In the above configuration, the particle diameter D 90 and particle diameter D 10 It is preferable that the difference between is 1 μm or less.

[0022] Particle size D 90 and particle diameter D 10 When the difference between the particle size and the particle diameter is 1 μm or less, the particle size can be said to be relatively uniform. Therefore, classification or the like is not required, and it is possible to provide zirconium phosphate with stable quality.

[0023] In the above configuration, the particle diameter D 90 and particle diameter D 10 It is preferable that the difference between them is 0.05 μm or more.

[0024] Particle size D 90 and particle diameter D 10 When the difference is 0.05 μm or more, zirconium phosphate having a uniform particle size can be provided.

[0025] In the above-mentioned composition, when the powder is dispersed in pure water at a solid content concentration of 50% by mass and measured with a particle gauge, it is preferable that no linear scratches are present at locations of 2.5 μm or more.

[0026] When dispersed in pure water at a solid content concentration of 50% by mass and measured with a particle gauge, the absence of linear scratches at locations of 2.5 μm or more means that even when dispersed in pure water at a solid content concentration of 50% by mass, no aggregates (coarse particles) of 2.5 μm or more are present. Therefore, according to the above configuration, even when dispersed in a water-based solvent at a high concentration, there is almost no aggregation of particles (powder), and it is possible to disperse almost uniformly.

[0027] The slurry according to the present invention is characterized in that the zirconium phosphate is dispersed in an aqueous solvent.

[0028] According to the above-mentioned configuration, it is possible to provide a novel slurry in which zirconium phosphate containing 3.1 to 3.6 phosphorus atoms per 2 zirconium atoms is dispersed in an aqueous solvent.

[0029] In the above-mentioned configuration, the zirconium phosphate is dispersed in the aqueous solvent at a solid content concentration of 50% by mass or more, It is preferable that the slurry is free of linear scratches at locations of 2.5 μm or more when measured with a grain gauge.

[0030] When zirconium phosphate is dispersed in an aqueous solvent at a solid content concentration of 50% by mass or more, and when the slurry is measured with a particle gauge, the absence of linear marks at locations of 2.5 μm or more means that the slurry does not contain aggregates (coarse particles) of 2.5 μm or more. Therefore, according to the above configuration, it is possible to provide a slurry in which zirconium phosphate is dispersed almost uniformly at a high concentration in an aqueous solvent. Effect of the Invention

[0031] According to the present invention, it is possible to provide zirconium phosphate containing 3.1 to 3.6 phosphorus atoms per 2 zirconium atoms (equivalent), and to provide a slurry in which the zirconium phosphate is dispersed in an aqueous solvent. [Brief description of the drawings]

[0032] [Figure 1] 1 is an X-ray diffraction spectrum of zirconium phosphate of Example 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited only to these embodiments. In this specification, the zirconium constituting zirconium phosphate contains inevitable impurities including hafnium as a part thereof. Further, in this specification, zirconium phosphate may contain impurities such as silica and titania other than hafnium in an amount of 1% by mass or less for reasons such as production.

[0034] [Zirconium Phosphate] The zirconium phosphate according to this embodiment is represented by the following formula [1]. M1Zr 2 (M2PO 4 ) a (PO 4 ) b ·nH 2 O [1]

[0035] In formula [1], M1 and M2 are monovalent cations, which may be the same or different from each other.

[0036] The monovalent cation is not particularly limited as long as it is a monovalent cation, and examples thereof include hydrogen ions, alkali metal ions, transition metal ions, and molecular ions having a monovalent charge. These may be used alone or in combination of a plurality. Examples of the alkali metal ions include Li, Na, K, Rb, Cs, Fr, and Ag. Examples of the molecular ion having a monovalent charge include ammonium ion (NH 4 + ), oxonium ion OH 3 + , etc. Note that a molecular ion having a monovalent charge refers to a molecule having a monovalent (+1) charge as a whole and composed of two or more atoms. From the viewpoint of easy ion exchange, among the monovalent cations, hydrogen ions and ammonium ions are particularly preferable.

[0037] In formula [1], a and b are numbers satisfying 0.3 < a ≤ 1.8, 3.1 ≤ (a + b) ≤ 3.6, and 2a + 3b = 9.

[0038] a+b is not particularly limited as long as it is 3.1 or more and 3.6 or less. From the viewpoint of improving dispersibility in aqueous solvents, a+b is preferably larger, for example, 3.2 or more is preferable, and 3.21 or more is more preferable. Also, from the viewpoint of containing a large amount of rhombohedral crystals, a+b is preferably smaller, for example, 3.55 or less is preferable, and 3.5 or less is more preferable. Methods for controlling a+b within the range of 3.1 or more and 3.6 or less include adjusting the mixing ratio of each raw material for producing zirconium phosphate, the mixing order, the mixing conditions (temperature, pressure, time), etc.

[0039] a is not particularly limited as long as it is greater than 0.3 and not greater than 1.8. From the viewpoint of dispersibility, a is preferably larger, for example, 0.31 or more is preferable, and 0.35 or more is more preferable. Also, from the viewpoint of particle size, a is preferably smaller, for example, 1.79 or less is preferable, and 1.75 or less is more preferable.

[0040] In formula [1], n is a number satisfying 0≦n≦2. n is not particularly limited as long as it is 0 or more and 2 or less. n is preferably larger, for example, preferably 0.05 or more, more preferably 0.1 or more. n is preferably smaller, for example, preferably 1.95 or less, more preferably 1.8 or less.

[0041] The zirconium phosphate according to the present embodiment has formula [1] in which (a+b) is 3.1 or more and 3.6 or less, and contains 3.1 to 3.6 phosphorus atoms per two zirconium atoms. Such a zirconium phosphate is a novel zirconium phosphate that has not been known before.

[0042] The zirconium phosphate preferably contains rhombohedral crystals as a crystal structure. The ratio of the rhombohedral crystals is preferably more than 90% of the entire zirconium phosphate, more preferably 92% or more, and even more preferably 95% or more. The ratio of the rhombohedral crystals is preferably as high as possible, but may be, for example, 100% or less, 99% or less, etc., of the entire zirconium phosphate. When the ratio of the rhombohedral crystals is 90% or more of the entire zirconium phosphate, a zirconium phosphate powder having a fine particle size and a relatively uniform particle size is easily obtained. The ratio of the rhombohedral crystals refers to a value obtained by the method described in the Examples. Methods for controlling the proportion of rhombohedral crystals to 90% or more include adjusting the mixing ratio of each raw material used to produce zirconium phosphate, the mixing order, and mixing conditions (temperature, pressure, time), etc.

[0043] (Particle diameter D 90 ) The particle diameter D of the zirconium phosphate 90 From the viewpoint of providing zirconium phosphate having a fine particle size, the particle size D is preferably 1.5 μm or less. 90 is more preferably 1.39 μm or less, further preferably 0.46 μm or less, and particularly preferably 0.28 μm or less. In addition, the zirconium phosphate has a number of phosphorus atoms of 3.1 or more and has a high affinity with water. 90 When the particle diameter D is 1.5 μm or less, it is possible to provide zirconium phosphate having a fine particle size and high dispersibility in an aqueous solvent. 90 From the viewpoint of providing zirconium phosphate with a fine particle size, the smaller the particle size, the more preferable, and it can be, for example, 0.05 μm or more, 0.1 μm or more, etc.

[0044] (Particle diameter D 90 and particle diameter D 10 (difference from Particle size D 90 and particle diameter D 10 The difference between the particle diameter D 90 ]-[Particle diameter D 10From the viewpoint of providing zirconium phosphate having a relatively uniform particle size, the difference is preferably 1 μm or less. The difference is more preferably 0.8 μm or less, further preferably 0.35 μm or less, and particularly preferably 0.11 μm or less. When the difference is 1 μm or less, classification or the like is not required, and zirconium phosphate having stable quality can be provided. The difference is preferably 0.05 μm or more, and more preferably 0.08 μm or more.

[0045] (Particle diameter D 10 ) The particle diameter D of the zirconium phosphate 10 From the viewpoint of providing zirconium phosphate having a fine particle size, it is preferable that the particle size is small, but is not particularly limited. 10 For example, the particle diameter D is preferably 0.59 μm or less, more preferably 0.24 μm or less, and further preferably 0.11 μm or less. 10 For example, the thickness can be preferably 0.01 μm or more, and more preferably 0.05 μm or more.

[0046] (Particle diameter D 50 ) The particle diameter D of the zirconium phosphate 50 From the viewpoint of providing zirconium phosphate having a fine particle size, it is preferable that the particle size is small, but is not particularly limited. 50 The particle diameter D can be, for example, 0.93 μm or less, preferably 0.45 μm or less, and more preferably 0.22 μm or less. 50 For example, the thickness can be 0.01 μm or more, preferably 0.05 μm or more.

[0047] The particle diameter D 10 , the particle diameter D 50 , the particle diameter D 90 The particle diameter D 10 , the particle diameter D 50 , the particle diameter D 90 is measured on a volume basis, and the particle diameter D10 is the particle size corresponding to a cumulative value of 10% from the minimum particle size value measured by a laser diffraction method, and the particle size D 50 is the particle size at 50% cumulatively from the minimum particle size measured by a laser diffraction method, and the particle size D 90 is the particle size that is 90% cumulatively larger than the minimum particle size, as measured by laser diffraction.

[0048] The zirconium phosphate is preferably dispersed in pure water at a solid content concentration of 50% by mass and measured with a particle gauge, with no linear scratches at a location of 2.5 μm or more. Dispersing in pure water at a solid content concentration of 50% by mass and measuring with a particle gauge means that no aggregates larger than 2.5 μm are present even when dispersed in pure water at a solid content concentration of 50% by mass. Therefore, even when dispersed in a water-based solvent at a high concentration, there is almost no aggregation of particles (powder), and the particles can be dispersed almost uniformly. Details of the measurement method using a grain gauge are as described in the Examples.

[0049] The above is about the zirconium phosphate according to this embodiment. 、 explained.

[0050] [Method of manufacturing zirconium phosphate] An example of a method for producing zirconium phosphate will be described below, however, the method for producing zirconium phosphate according to the present invention is not limited to the following example.

[0051] The method for producing zirconium phosphate according to this embodiment is as follows: A step A of preparing an aqueous solution containing a zirconium compound, a compound having two or more carboxyl groups, and a phosphoric acid compound in a predetermined ratio; and step B of heating the aqueous solution.

[0052] In the method for producing zirconium phosphate according to this embodiment, first, an aqueous solution containing a zirconium compound, a compound having two or more carboxyl groups, and a phosphate compound in a predetermined ratio is prepared (Step A).

[0053] Examples of the zirconium compound include zirconium halides such as zirconium oxychloride, zirconium hydroxide chloride, zirconium tetrachloride, and zirconium bromide, zirconium salts of mineral acids such as zirconium sulfate, basic zirconium sulfate, and zirconium nitrate, zirconium salts of organic acids such as zirconyl acetate and zirconyl formate, and zirconium complex salts such as ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, and ammonium zirconium citrate. Among these compounds, zirconium oxychloride and zirconium sulfate are more preferable from the viewpoint of productivity.

[0054] Examples of compounds having two or more carboxyl groups include aliphatic dibasic acids and their salts, such as oxalic acid, sodium oxalate, sodium hydrogen oxalate, ammonium oxalate, ammonium hydrogen oxalate, lithium oxalate, maleic acid, malonic acid, succinic acid, and their salts; aliphatic oxyacids and their salts, such as citric acid, ammonium citrate, tartaric acid, malic acid, etc. Among these, oxalic acid and its sodium salt and ammonium salt are more preferred. Among the zirconium compounds, zirconium compounds of carboxylic acids having two or more carboxyl groups, such as sodium zirconium oxalate and ammonium zirconium citrate, form complexes with excellent stability in the mixed solution, similar to compounds having two or more carboxyl groups. Therefore, even when used as a zirconium compound, the carboxyl groups are not included in the C in the mixed solution. 2 O 4 is counted as

[0055] Examples of the phosphoric acid compound include alkali metal salts and ammonium salts of orthophosphoric acid such as phosphoric acid, monosodium phosphate, disodium phosphate, and trisodium phosphate, and alkali metal salts and ammonium salts of condensed phosphoric acid having at least one POP bond such as metaphosphoric acid and pyrophosphoric acid. Among these, alkali metal salts and ammonium salts of orthophosphoric acid are more preferred.

[0056] The mixing ratio of the zirconium compound, the compound having two or more carboxyl groups, and the phosphate compound is preferably within the range of 0.75-1.2:0.75-1.2:1.3-1.7 in terms of molar ratio. When the mixing ratio of the zirconium compound, the compound having two or more carboxyl groups, and the phosphate compound is within the above-mentioned numerical range, it is easy to obtain zirconium phosphate that contains a large amount of rhombohedral crystals and also contains a large amount of phosphate ions and hydrogen phosphate ions. In particular, the present inventors have found that the crystal phase obtained differs depending on the content ratio of the compound having two or more carboxyl groups (particularly, oxalic acid). In the production of the zirconium phosphate, by setting the mixing ratio of the compound having two or more carboxyl groups within the above-mentioned numerical range, it is possible to increase the content of rhombohedral crystals and the content of phosphorus atoms.

[0057] In the step A, the order of mixing the raw materials is not particularly limited, but it is preferable to mix the phosphoric acid compound into the aqueous solution of the zirconium compound, and then mix the compound having two or more carboxyl groups. Rhombohedral crystals are more likely to be obtained if a phosphoric acid compound is first mixed into an aqueous solution of a zirconium compound, and then a compound having two or more carboxyl groups is mixed in. If a compound having two or more carboxyl groups is first mixed into an aqueous solution of a zirconium compound, monoclinic crystals are more likely to be formed when the phosphoric acid compound is mixed in, making it difficult to obtain rhombohedral crystals.

[0058] After mixing the above-mentioned raw materials, the pH may be adjusted as necessary. The pH is preferably in the range of 1.0 to 4.0, more preferably in the range of 1.5 to 3.5, and even more preferably in the range of 2.0 to 3.0. By adjusting the pH to within the above range, the reaction rate of zirconium phosphate can be controlled.

[0059] Examples of pH adjusters for adjusting the pH include mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid; ammonium hydroxide (aqueous ammonia), ammonium hydrogen carbonate, sodium hydroxide, potassium hydroxide, and sodium carbonate; and hydroxides and carbonates of alkali metals.

[0060] Next, the obtained aqueous solution is heated (step B). The heating temperature is not particularly limited, but from the viewpoint that the higher the temperature, the easier it is to obtain rhombohedral crystals, examples of the heating temperature include 90°C or higher, preferably 100°C or higher, and more preferably 150°C or higher. The upper limit of the heating temperature is not particularly limited, but examples of the heating temperature include 200°C or lower, preferably 190°C or lower, and more preferably 180°C or lower.

[0061] The heating step (step B) may be carried out under normal pressure (approximately standard atmospheric pressure (101.33 kPa)) or under pressurized conditions. From the viewpoint of easiness of obtaining rhombohedral crystals, it is preferable to carry out the heating step under pressurized conditions. When pressurized, examples of the pressurized conditions include 0.1 MPa or more, 0.2 MPa or more, 0.5 MPa or more, etc. In addition, the upper limit of the pressurized conditions is not particularly limited, but examples thereof include 1.0 MPa or less, preferably 0.9 MPa or less, and more preferably 0.8 MPa or less.

[0062] The time for which the heating step (step B) is performed can vary greatly depending on the type of raw materials (i.e., the reactivity of the raw materials), the mixing ratio of the raw materials, the concentration of the aqueous solution, the temperature, the pH, the desired crystallinity of the reaction product, etc., but for example, when the temperature is 150°C, the time can be 1 hour or more (a large amount of unreacted components), preferably 2 hours or more, and more preferably 3 hours or more (almost all of the amount is crystallized).

[0063] After the heating process, the temperature is usually returned to room temperature (around 25°C) and normal pressure.

[0064] Next, if necessary, the precipitate is thoroughly washed with water to remove excess ions, and then dried to obtain the zirconium phosphate according to the present embodiment. There are no particular limitations on the drying conditions, but the drying temperature is preferably within the range of 50°C to 150°C.

[0065] [slurry] The slurry according to the present embodiment is obtained by dispersing the zirconium phosphate in an aqueous solvent, that is, the slurry according to the present embodiment includes an aqueous solvent and the zirconium phosphate dispersed in the aqueous solvent.

[0066] The aqueous solvent is not particularly limited as long as it contains water at 50% by mass or more (more preferably 55% by mass or more, and further preferably 60% by mass or more). Solvents other than water that may be contained in the aqueous solvent are not particularly limited, and examples thereof include alcohols having 1 to 4 carbon atoms, ethanol, methanol, butanol, and propanol. Of these, the aqueous solvent is preferably pure water.

[0067] The method for dispersing the zirconium phosphate in the aqueous solvent is not particularly limited, and the zirconium phosphate (powder) may be added to the aqueous solvent and stirred. The stirring conditions are not particularly limited, and the stirring may be performed at room temperature under pressure until no solid content is visible to the naked eye.

[0068] In the slurry, the zirconium phosphate is dispersed in the aqueous solvent at a solid content concentration of preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more.

[0069] It is preferable that the slurry is free of linear scratches at locations of 2.5 μm or more when measured with a grain gauge.

[0070] When zirconium phosphate is dispersed in an aqueous solvent at a solid content concentration of 50% by mass or more, and when the slurry is measured with a particle gauge, the absence of linear marks at locations of 2.5 μm or more means that the slurry does not contain aggregates (coarse particles) of 2.5 μm or more. Therefore, the slurry can provide a slurry in which zirconium phosphate is dispersed almost uniformly in an aqueous solvent at a high concentration. EXAMPLES

[0071] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples as long as it does not exceed the gist of the present invention. The zirconium phosphate and slurry in the examples and comparative examples contain 1.3 to 2.5 mass% of hafnium as an inevitable impurity in terms of oxide relative to zirconium (calculated by the following formula (X)). In addition to hafnium, the zirconium phosphate and slurry in the examples and comparative examples may contain silica and titania as impurities in an amount of 0.1 mass% or less due to manufacturing reasons. <Expression(X)> ([Mass of hafnium oxide] / ([Mass of zirconium oxide]+[Mass of hafnium oxide]))×100(%)

[0072] Furthermore, the maximum and minimum values ​​of the content of each component shown in the following examples should be considered as the preferred minimum and maximum values ​​of the present invention, regardless of the contents of other components. Furthermore, the maximum and minimum values ​​of the measured values ​​shown in the following examples should be considered as the preferred minimum and maximum values ​​of the present invention, regardless of the content (composition) of each component.

[0073] <Preparation of zirconium phosphate> Example 1 Zirconium oxychloride (ZrOCl) in 300 ml of pure water 2 0.1 mol of was dissolved. Next, monosodium phosphate (NaH 2 PO 4) was mixed in 0.15 mol. Next, 0.1 mol of oxalic acid (HOOC-COOH) was added in the form of an aqueous solution. The concentration of the added oxalic acid aqueous solution was 5% by mass. Next, the pH was adjusted to 2.7 using 25% by mass of ammonia water. The operations up to this point were carried out at room temperature (25°C) and under normal pressure.

[0074] Next, the mixture was stirred at 150° C. under pressure (pressure: 0.5 MPa) for 3 hours, and then returned to room temperature (25° C.) and normal pressure.

[0075] Next, the precipitate was thoroughly washed with water to remove excess ions, and then dried at 100° C. In this manner, the zirconium phosphate according to Example 1 was obtained.

[0076] Example 2 Monoammonium phosphate (NH) is used instead of monosodium phosphate. 4 H 2 PO 4 A zirconium phosphate according to Example 2 was obtained in the same manner as in Example 1, except that 2-methyl-2-propanediol was used.

[0077] Example 3 A zirconium phosphate according to Example 3 was obtained in the same manner as in Example 1, except that the amount of oxalic acid added was changed to 0.075 mol, and stirring was carried out at 98° C. under normal pressure for 14 hours.

[0078] Example 4 The zirconium phosphate obtained in Example 1 was heated at 650° C. for 5 hours to obtain the zirconium phosphate according to Example 4.

[0079] Example 5 Zirconium phosphate according to Example 5 was obtained in the same manner as in Example 1, except that a 25% by mass aqueous solution of sodium hydroxide was used instead of the 25% by mass aqueous ammonia.

[0080] Example 6 Zirconium phosphate according to Example 6 was obtained in the same manner as in Example 1, except that the amount of oxalic acid added was changed to 0.12 mol.

[0081] Example 7 0.1 mole of the zirconium phosphate powder obtained in Example 4 was weighed out. Next, lithium nitrate (LiNO 3 ) 0.05 mol was mixed in powder form. Then, it was heated at 500°C for 3 hours to obtain zirconium phosphate according to Example 7.

[0082] Example 8 Silver nitrate (AgNO) instead of lithium nitrate 3 A zirconium phosphate according to Example 8 was obtained in the same manner as in Example 7, except that 2,4-dichlorophenyl phosphate (C10), ...

[0083] Comparative Example 1 Add oxalic acid dihydrate (COOH) to 300 ml of pure water. 2 2H 2 O) 0.1 mole and zirconium oxychloride octahydrate (ZrOCl 2 8H 2 0.195 moles of phosphoric acid (H 3 PO 4 0.3 mol of ammonium hydroxide was added. Next, the pH was adjusted to 2.7 using 25% by mass of aqueous ammonia. The operations up to this point were carried out at room temperature (25° C.) and under normal pressure.

[0084] Next, the mixture was stirred at 150° C. under pressure (pressure: 0.5 MPa) for 3 hours, and then returned to room temperature (25° C.) and normal pressure.

[0085] Next, the precipitate was thoroughly washed with water to remove excess ions, and then dried at 100° C. In this manner, zirconium phosphate according to Comparative Example 1 was obtained.

[0086] Comparative Example 2 Add oxalic acid dihydrate (COOH) to 300 ml of pure water. 2 2H 2 O)) and 0.1 mole of zirconium oxychloride octahydrate (ZrOCl 2 8H 2 0.195 moles of phosphoric acid (H 3 PO4 0.3 mol of sodium hydroxide was then added. The pH was then adjusted to 2.7 using a 25% by mass aqueous solution of sodium hydroxide. The operations up to this point were carried out at room temperature (25° C.) and under normal pressure.

[0087] Next, the mixture was stirred at 98° C. under normal pressure for 14 hours, and then cooled to room temperature (25° C.).

[0088] Next, the precipitate was thoroughly washed with water to remove excess ions, and then dried at 100° C. In this manner, zirconium phosphate according to Comparative Example 2 was obtained.

[0089] Comparative Example 3 Zirconium phosphate according to Comparative Example 3 was obtained in the same manner as in Comparative Example 1, except that stirring was performed at 98°C under normal pressure for 24 hours instead of at 150°C under pressure (pressure: 0.5 MPa) for 3 hours.

[0090] Comparative Example 4 A zirconium phosphate according to Comparative Example 4 was obtained in the same manner as in Example 1, except that the amount of oxalic acid added was changed to 0.15 mol.

[0091] The zirconium phosphates obtained in the Examples and Comparative Examples were all in powder form. In the analyses described below, the zirconium phosphates obtained in the Examples and Comparative Examples were dried at 110° C. for 3 hours to obtain powders.

[0092] [Identification of crystalline phases] For the zirconium phosphate of the examples and comparative examples, an X-ray diffraction spectrum was obtained using an X-ray diffractometer ("RINT2500" manufactured by Rigaku Corporation). The measurement conditions were as follows. <Measurement conditions> Measurement equipment: X-ray diffraction equipment (Rigaku, RINT2500) Source: CuKα source Tube voltage: 50kV Tube current: 300mA Scanning speed: 2θ=5~60°: 4° / min.

[0093] Thereafter, the crystal phases were identified from the X-ray diffraction spectrum. The ratio of each crystal phase contained in the zirconium phosphate was calculated using the following formula. The results are shown in Table 1. For Example 5, the X-ray diffraction spectrum is shown in FIG. 1. Rhombohedral phase ratio (%)=Ir(116) / (Ir(116)+Im(001)+Ic(111))×100 Cubic phase rate (%)=(100%-rhombohedral phase rate (%))×((Ic(111)) / (Im(001)+Ic(111))×100 Monoclinic fraction (%) = (100% - rhombohedral fraction (%)) × (Im(001)) / (Im(001) + Ic(111)) × 100 The rhombohedral phase of zirconium phosphate was distinguished from the cubic phase and monoclinic phase at 2θ=5 to 35° in the XRD spectrum, and the cubic phase was distinguished from the monoclinic phase at 2θ=5 to 15° in the XRD spectrum. Here, Ir(116) is the diffraction intensity of (116) in the rhombohedral phase, Ic(111) is the diffraction intensity of (111) in the cubic phase, and Im(001) is the diffraction intensity of (001) in the monoclinic phase.

[0094] [Particle size D 10 , particle diameter D 50 , and particle diameter D 90 Measurement of 0.15 g of zirconium phosphate (powder) of each of the Examples and Comparative Examples and 40 ml of 0.2% aqueous sodium hexametaphosphate solution were placed in a 50 ml beaker and dispersed for 5 minutes using a tabletop ultrasonic cleaner "W-113" (manufactured by Honda Electronics Co., Ltd.), and then placed in an apparatus (laser diffraction particle size distribution measuring apparatus ("LA-950" manufactured by Shimadzu Corporation)) to measure the particle diameter D 10 , particle diameter D 50 (median diameter) and particle diameter D 90 The results are shown in Table 1.

[0095] [Table 1]

[0096] [Analysis of zirconium phosphate composition] The compositions (in terms of oxide) of the zirconium phosphates produced in the examples and comparative examples were analyzed using an ICP-AES ("ULTIMA-2" manufactured by HORIBA).

[0097] As a result, it was found that the compositions of the zirconium phosphates prepared in the examples and comparative examples were as follows. Example 1: (NH 4 )Zr 2 (NH 4 PO 4 ) 1.5 (PO 4 ) 2 2H 2 O Example 2: (NH 4 )Zr 2 (NH 4 PO 4 ) 1.5 (PO 4 ) 2 2H 2 O Example 3: (NH 4 )Zr 2 (NH 4 PO 4 ) 0.6 (PO 4 ) 2.6 2H 2 O Example 4: HZr 2 (HPO 4 ) 1.5 (PO 4 ) 2 0.1H 2 O Example 5: NaZr 2 (NaPO 4 ) 0.6 (PO 4 ) 2.6 1.2H 2 O Example 6: (NH 4 )Zr 2 (NH 4 PO 4 ) 1.8 (PO 4 ) 1.8 2H 2 O Example 7: LiZr2 (HPO 4 ) 1.5 (PO 4 ) 2 0.1H 2 O Example 8: AgZr 2 (HPO 4 ) 1.5 (PO 4 ) 2 0.1H 2 O Comparative example 1: (NH 4 ) 0.85 Zr 2 (PO 4 ) 2.95 2H 2 O Comparative Example 2: Na 0.85 Zr 2 (PO 4 ) 2.95 2H 2 O Comparative example 3: (NH 4 ) 0.85 Zr 2 (PO 4 ) 2.95 2H 2 O Comparative example 4: Zr(PO 4 )(NH 4 HPO 4 )·2H 2 O

[0098] The results of the weight analysis of the zirconium phosphates of Example 5 and Comparative Example 2 are shown in Table 2.

[0099] [Table 2]

[0100] In the above-mentioned Examples 1 to 6, the cases where M1 and M2 are the same have been described. However, as described above, in the present invention, they may be the same or different from each other. As a method for making M1 and M2 different, for example, the (NH 4 )Zr 2 (NH 4PO 4 ) 1.5 (PO 4 ) 2 2H 2 NH equivalent to M1 of O 4 For example, M2 is exchanged with H by ion exchange. Since M2 is usually present within the crystal lattice, it remains untouched during ion exchange, and only M1 is exchanged. Another method for making M1 and M2 different is to mix lithium nitrate or silver nitrate with the zirconium phosphate powder obtained in Example 4 and bake the mixture to exchange H corresponding to M1 for Li or Ag, as in Examples 7 and 8 described above. Furthermore, in Examples 7 and 8, a method was described in which the zirconium phosphate powder obtained in Example 4 was mixed with lithium nitrate or silver nitrate and fired to exchange H corresponding to M1 for Li or Ag. However, the present invention is not limited to this example. The zirconium phosphate powder obtained in Example 4 can be mixed with a metal salt such as an alkali metal other than Li and Ag, that is, a nitrate of Na, K, Rb, Cs, or Fr, and fired to exchange H corresponding to M1 for Na, K, Rb, Cs, or Fr.

[0101] [Dispersibility evaluation] The zirconium phosphates prepared in the examples and comparative examples were dispersed in pure water. The results were as follows. Whether or not the dispersion was successful was judged by visual observation. Example 1: Dispersible in pure water at a solid content concentration of 70% by mass Example 2: Dispersible in pure water at a solid content of 70% by mass Example 3: Dispersible in pure water at a solid content concentration of 55% by mass Example 4: Dispersible in pure water at a solid content concentration of 60% by mass Example 5: Dispersible in pure water at a solid content of 70% by mass Example 6: Dispersible in pure water at a solid content concentration of 60% by mass Example 7: Dispersible in pure water at a solid content concentration of 50% by mass Example 8: Dispersible in pure water at a solid content concentration of 50% by mass Comparative Example 1: At a solid content concentration of 60% by mass, the fluidity was lost and the material was not dispersed in pure water. At a solid content concentration of 50% by mass, the material was dispersible in pure water. Comparative Example 2: Dispersible in pure water at a solid content of 60% by mass Comparative Example 3: At a solid content concentration of 60% by mass, the fluidity was lost and the material was not dispersed in pure water, but at a solid content concentration of 50% by mass, the material was dispersible in pure water. In addition, in Comparative Example 4, the particle diameter D 10 Since the value was 4.72 μm and particles exceeding 2.5 μm were present, dispersibility evaluation and aggregation evaluation were not performed.

[0102] [Agglomeration evaluation] For Example 1, Example 2, and Example 5, a slurry was prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 70 mass %. Next, the size of the particles (powder or powder aggregates) of the prepared slurry was evaluated using a grain gauge (manufactured by Hosen Co., Ltd., product name: grind meter / large / 2 grooves / 0-25 μm) in accordance with JIS-K5600-2-5. As a result, no linear marks were present at locations with a particle size of 2.5 μm or more. This result means that the slurry does not contain aggregates with a particle size exceeding 2.5 μm.

[0103] For Examples 4 and 6, slurries were prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 60% by mass. As with the above, the size of the particles (powder or powder aggregates) of the prepared slurries was evaluated using a particle gauge in accordance with JIS-K5600-2-5. As a result, no linear marks were present in areas of 2.5 μm or more.

[0104] For Examples 7 and 8, slurries were prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 50% by mass. As with the above, the size of the particles (powder or powder aggregates) of the prepared slurries was evaluated using a particle gauge in accordance with JIS-K5600-2-5. As a result, no linear marks were present in areas of 2.5 μm or more.

[0105] For Example 3, a slurry was prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 55% by mass. As with the above, the size of the particles (powder or powder aggregates) of the prepared slurry was evaluated using a particle gauge in accordance with JIS-K5600-2-5. As a result, no linear marks were present in areas of 2.5 μm or more. Furthermore, the fact that no linear scratches were present at locations above 2.5 μm in slurries with solid content concentrations of 70, 60, and 55% by mass naturally means that if a similar evaluation were performed with a slurry with a solid content concentration of 50% by mass, no linear scratches would be present at locations below 2.5 μm.

[0106] For Comparative Examples 1 and 3, slurries were prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 50% by mass. As described above, the size of the particles (powder or powder aggregates) of the prepared slurries was evaluated using a particle gauge in accordance with JIS-K5600-2-5. As a result, linear scratches were observed at locations exceeding 2.5 μm. This result means that the slurry contains aggregates with a particle size exceeding 2.5 μm.

[0107] For Comparative Example 2, a slurry was prepared by dispersing zirconium phosphate in pure water at a solid content concentration of 50% by mass. As with the above, the size of the particles (powder or powder aggregates) of the prepared slurry was evaluated using a particle gauge in accordance with JIS-K5600-2-5. As a result, linear scratches were observed in areas exceeding 2.5 μm.

Claims

1. Represented by the following formula [1]: Particle diameter D ９０ and particle diameter D １０ The difference between the thickness and the thickness of zirconium phosphate is 1 μm or less. M1Zr ２ (M2PO ４ ) ａ (P.O. ４ ) ｂ ・nH ２ O [1] In formula [1], M1 and M2 are monovalent cations and may be the same or different, a and b are numbers that satisfy 0.3<a≦1.8, 3.1≦(a+b)≦3.6, and 2a+3b=9 (excluding the case where (a+b) is less than 3.32), and n is a number that satisfies 0≦n≦2.

2. The crystal structure includes rhombohedral crystals.

2. The zirconium phosphate according to claim 1, wherein the proportion of rhombohedral crystals is greater than 90% based on the entire zirconium phosphate.

3. Particle diameter D ９０ 3. The zirconium phosphate according to claim 1, wherein the average particle size is 1.5 μm or less.

4. Particle diameter D ９０ and particle diameter D １０ The zirconium phosphate according to any one of claims 1 to 3, characterized in that the difference between the above and the above is 0.05 µm or more.

5. The zirconium phosphate according to any one of claims 1 to 4, characterized in that when dispersed in pure water at a solid content concentration of 50 mass% and measured with a particle gauge, no linear scratches are present at locations of 2.5 μm or more.

6. A slurry comprising the zirconium phosphate according to any one of claims 1 to 5 dispersed in an aqueous solvent.

7. The zirconium phosphate is dispersed in the aqueous solvent at a solid content concentration of 50% by mass or more, 7. The slurry according to claim 6, wherein the slurry is free of linear marks at locations of 2.5 μm or more when measured with a grain gauge.

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