WO2017057636A1 - Zirconium oxide nanoparticles - Google Patents

Abstract

The purpose of the present invention is to easily obtain, without using or using a smaller amount of a sulfate aqueous solution such as a MgSO₄ aqueous solution, zirconium oxide particles which include metallic elements such as rare earth oxides (preferably stabilized with a metallic element) and which exhibit good dispersibility with respect to an organic medium. These zirconium oxide nanoparticles are coated with a first carboxylic acid which has three or more carbon atoms and which is at least one type of a primary carboxylic acid and a secondary carboxylic acid. The zirconium oxide nanoparticles include at least one type of metallic element M selected from the group consisting of rare earth elements, Al, Fe, Co, Sn, Zn, In, Bi, Mn, Ni, and Cu.

Description

Zirconium oxide nanoparticles

The present invention relates to zirconium oxide nanoparticles.

In recent years, metal oxide nanoparticles have the potential to develop various functions in optical materials, pharmaceuticals, ceramics, electronic component materials, and the like, and are attracting attention in the field of various functional materials. However, metal oxides alone are often agglomerated due to insufficient dispersibility in an organic medium, causing problems such as a decrease in transparency and a decrease in mechanical strength. In order to impart good dispersibility to an organic medium, a method of chemically bonding an organic group to a metal oxide has been proposed.

For example, Patent Document 1 is coated with two or more coating agents, and at least one of the coating agents is represented by the formula R ¹ —COOH (R ¹ is a hydrocarbon group having 6 or more carbon atoms). Zirconium oxide nanoparticles are disclosed, and it is described that such zirconium oxide nanoparticles can improve dispersibility in a nonpolar solvent or the like. As the coating agent represented by the above formula, neodecanoic acid is disclosed in Examples of Patent Document 1.

Also, the functions of single metal oxide nanoparticles are limited, and composite oxide nanoparticles that may exhibit more specific performance have attracted attention.

In recent years, techniques for stabilizing metal oxide particles with rare earth oxides have been proposed. Neodecanoic acid disclosed in Patent Document 1 is classified as a tertiary carboxylic acid. Non-Patent Document 1 discloses a rare earth oxide (yttrium oxide) using a metal complex of a tertiary carboxylic acid as a starting material. ) Stabilized zirconia microparticles. In Non-Patent Document 1, zirconia particles are generated by hydrothermal synthesis with an aqueous MgSO ₄ solution using a solution obtained by mixing Zr (IV) -carboxylate and Y (III) -carboxylate in a predetermined ratio as a starting material. Is disclosed.

Furthermore, as composite oxide nanoparticles, for example, Patent Document 2 discloses stabilized zirconia fine particles containing yttrium or the like. Patent Document 3 discloses a zirconium oxide dispersion containing aluminum, magnesium, titanium, or yttrium as a stabilizing element.

Also, zirconia nanoparticles are expected to be applied to ceramic materials. For example, Patent Documents 4 to 6 disclose colored stabilized zirconia sintered bodies. In each of Patent Documents 4 to 6, a plurality of types of metal oxides are separately prepared as raw materials, mixed with a ball mill or the like, molded, and sintered. However, when multiple types of raw materials are prepared and mixed separately, mixing of different types of raw materials is uneven, and when a ball mill is used, impurities are mixed from the mill or the particle size is uneven. It becomes. Ceramics sintered by such a method have a problem that transparency is lowered due to grain boundaries and coloration is not uniform.

JP 2008-44835 A JP 2008-184339 A JP 2014-80361 A Special table 2010-501465 gazette JP 2012-116745 A JP 2013-230981 A

"Rare earth oxide stabilized zirconia fine particles starting from metal carboxylate", Abstracts of Annual Meeting of Chemical Engineering Society, Chemical Engineering Society Autumn Meeting, 2001, 34, 16

The present invention includes a metal element such as a rare earth oxide without using a sulfate aqueous solution such as MgSO ₄ aqueous solution disclosed in Non-Patent Document 1 described above or reducing the amount of use thereof (preferably a metal element). The first object is to easily obtain zirconium oxide particles that are stabilized and exhibit good dispersibility in an organic medium.

In addition to the stabilizing elements disclosed in Patent Documents 2 and 3, it is not clear whether composite oxide nanoparticles composited with zirconium oxide can be obtained. It is also not clear whether a particle coated with a coating can be realized.

Therefore, a second object of the present invention is to find an element that can be combined with zirconium oxide nanoparticles and provide composite zirconium oxide nanoparticles coated with a coating agent.

Furthermore, in a preferred embodiment, the third object of the present invention is to provide zirconium oxide nanoparticles useful as a precursor (raw material) for ceramics having excellent transparency and color uniformity.

The present invention is as follows.
(1) Zirconium oxide nanoparticles coated with a first carboxylic acid that is at least one of a primary carboxylic acid and a secondary carboxylic acid and has 3 or more carbon atoms,
The zirconium oxide nanoparticles are at least one selected from the group M consisting of rare earth elements, Al, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu.

(2) The first carboxylic acid is at least one selected from the group consisting of secondary carboxylic acids, carboxylic acids having branched carbon atoms other than the α-position, and linear carboxylic acids having 4 to 20 carbon atoms. The zirconium oxide nanoparticles according to (1), wherein

(3) In the above (1) or (2), the zirconium oxide nanoparticles contain at least one selected from the group consisting of Y, Al, La, Ce and In among the elements belonging to the group M. The zirconium oxide nanoparticles described.

(4) The zirconium oxide nanoparticles contain at least one selected from the group consisting of Fe, Co, Mn, Ni and Cu while containing Y among the elements belonging to the group M (1) ) Or zirconium oxide nanoparticles according to (2).

(5) the zirconium oxide particles, among the elements belonging to the group M, containing at least one element selected from the group M _a consisting rare earth elements and Al, the total content of elements belonging to the group M _a is , zirconium oxide nanoparticles according to the is 0.1 mass% or more at a ratio (1) or (2) to the total content of the elements and zirconium belonging to the group M _a.

(6) the zirconium oxide particles, among the elements belonging to the group M, La, Ce, Fe, Co, Sn, Zn, In, at least one selected Bi, Mn, from a group M _b consisting of Ni and Cu containing seeds, the total content of elements belonging to the group M _b is the 0.1 to 20 mass% in a ratio to the total content of the elements and zirconium belonging to the group of M _b (1) or (2 ) Zirconium oxide nanoparticles as described above.

(7) Said (1) coat | covered with at least 1 sort (s) selected from organic acid other than said 1st carboxylic acid, a silane coupling agent, surfactant, an organic phosphorus compound, and an organic sulfur compound. The zirconium oxide nanoparticles according to any one of (6) to (6).

(8) The zirconium oxide nanoparticles according to any one of (1) to (7), which are precursors of a sintered zirconium oxide.

(9) A dispersion containing the zirconium oxide nanoparticles according to any one of (1) to (8).

(10) A resin composition comprising the zirconium oxide nanoparticles according to any one of (1) to (8).

(11) A molding material containing the zirconium oxide nanoparticles according to any one of (1) to (8).

(12) A ceramic material obtained from the zirconium oxide nanoparticles according to any one of (1) to (8).

(13) A method for producing a ceramic material, wherein the zirconium oxide nanoparticles according to any one of (1) to (8) are fired at 500 ° C. or higher.

(14) A method for producing a ceramic material, comprising firing the composition containing the zirconium oxide nanoparticles according to any one of (1) to (8) above at 500 ° C. or higher.

(15) The method for producing zirconium oxide nanoparticles according to any one of (1) to (8),
A zirconium source material composed of the first carboxylic acid and zirconium or a zirconium-containing compound;
A source material of the element belonging to the group M composed of at least one element belonging to the group M and a compound containing the element belonging to the group M, and the first carboxylic acid,
A method for producing zirconium oxide nanoparticles, characterized by hydrothermal synthesis without using MgSO ₄ .

According to the invention, the zirconium oxide nanoparticles coated with a coating agent are selected from the group M consisting of rare earth elements, Al, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu. Zirconium oxide nanoparticles containing at least one kind can be provided.

According to the present invention, since a specific carboxylic acid is used, zirconium oxide nanoparticles coated with a carboxylic acid and containing a predetermined metal element such as a rare earth element can be used without using MgSO ₄ or the like. It can be obtained easily by reducing the amount used. Such a zirconium oxide nanoparticle exhibits a good dispersibility in an organic medium because a specific carboxylic acid is used, and in a preferred embodiment, a specific metal element (aluminum, yttrium, Since it has a stable crystal structure by containing lanthanum, cerium and indium), when the zirconium oxide nanoparticles are fired, changes in the crystal structure can be suppressed.

Furthermore, according to a preferred embodiment of the present invention, the transition metal element (specifically, at least one selected from the group consisting of Fe, Co, Mn, Ni and Cu) is included together with yttrium, and is coated with a carboxylic acid. Zirconium oxide nanoparticles thus obtained can be realized, and ceramics fired using such nanoparticles (including sintered ceramics; the same shall apply hereinafter) are excellent in transparency and color uniformity.

FIG. 1 is an X-ray diffraction chart of lanthanum-containing zirconia nanoparticles. FIG. 2 is an X-ray diffraction chart of tin-containing zirconia nanoparticles. FIG. 3 is an X-ray diffraction chart of zinc-containing zirconia nanoparticles. FIG. 4 is an X-ray diffraction chart of cerium-containing zirconia nanoparticles. FIG. 5 is an X-ray diffraction chart of indium-containing zirconia nanoparticles. FIG. 6 is an X-ray diffraction chart of bismuth-containing zirconia nanoparticles. FIG. 7 is an X-ray diffraction chart of iron-containing zirconia nanoparticles. FIG. 8 is a graph showing the absorbance of zirconium oxide ceramics obtained by firing the zirconium oxide nanoparticles of the present invention. FIG. 9 is a graph showing the X-ray diffraction patterns of the samples after firing in Examples and Comparative Examples.

Since the zirconium oxide nanoparticles of the present invention are coated with the specific first carboxylic acid, they have good dispersibility in organic media such as solvents and resins. Further, since the specific first carboxylic acid is used, it is required when a metal complex of a tertiary carboxylic acid as described in Non-Patent Document 1 is used as a starting material, and MgSO ₄ that performs a catalytic function. Even without using an aqueous solution, zirconium oxide nanoparticles can be obtained by hydrothermal synthesis.

The first carboxylic acid in the present invention is at least one of a primary carboxylic acid and a secondary carboxylic acid and has 3 or more carbon atoms (excluding formic acid and acetic acid). The carbon number of the first carboxylic acid is preferably 4 or more, more preferably 5 or more. Although the upper limit of carbon number is not specifically limited, For example, it is 22 or less, Preferably it is 20 or less, More preferably, it is 18 or less. The primary carboxylic acid means a carboxylic acid in which the carbon atom adjacent to the carboxyl group is bonded to one carbon atom and two hydrogen atoms, and the secondary carboxylic acid means two carbon atoms adjacent to the carboxyl group. A carboxylic acid bonded to a carbon atom and one hydrogen atom is meant, and a tertiary carboxylic acid means a carboxylic acid in which the carbon atom adjacent to the carboxyl group is bonded to three carbon atoms.

Examples of the primary carboxylic acid include linear primary carboxylic acid and branched primary carboxylic acid (that is, carboxylic acid in which carbon atoms other than α-position are branched), and among them, the number of carbon atoms is 4 or more (more preferably 5 or more, more preferably 8 or more) 20 or less linear carboxylic acid, and carboxylic acid in which carbon atoms other than α-position are branched are preferable.

The first carboxylic acid is preferably a secondary carboxylic acid, a carboxylic acid having a branched carbon atom other than the α-position, or a linear carboxylic acid having 4 to 20 carbon atoms, and is coated with at least one of these. It is preferable. Of these, the secondary carboxylic acid and the carboxylic acid having a branched carbon atom other than the α-position are more preferably coated and more preferably the secondary carboxylic acid.

The secondary carboxylic acid is preferably a secondary carboxylic acid having 4 to 20 carbon atoms, more preferably a secondary carboxylic acid having 5 to 18 carbon atoms, specifically isobutyric acid, 2-methylbutyric acid, 2-ethylbutyric acid. 2-ethylhexanoic acid, 2-methylvaleric acid, 2-methylhexanoic acid, 2-methylheptanoic acid, 2-propylbutyric acid, 2-hexylvaleric acid, 2-propylbutyric acid, 2-hexyldecanoic acid, 2-heptylundecane Acid, 2-methylhexadecanoic acid, 4-methylcyclohexacarboxylic acid and the like. Among these, at least one of 2-ethylhexanoic acid and 2-hexyldecanoic acid is preferable, and 2-ethylhexanoic acid is particularly preferable.

The carboxylic acid having a branched carbon atom other than the α-position means a carboxylic acid having a carboxyl group bonded to a hydrocarbon group and having a branched carbon atom other than the α-position of the hydrocarbon group. Such carboxylic acids preferably have 4 to 20 carbon atoms, more preferably 5 to 18 carbon atoms, such as isovaleric acid, 3,3-dimethylbutyric acid, 3-methylvaleric acid, isononanoic acid, 4-methylvaleric acid. 4-methyl-n-octanoic acid, naphthenic acid and the like.

The carbon number of a linear carboxylic acid having 4 to 20 carbon atoms (preferably a linear saturated aliphatic carboxylic acid) is preferably 5 or more, more preferably 8 or more. Examples of linear carboxylic acids having 4 to 20 carbon atoms include butyric acid, valeric acid, hexanoic acid, heptanoic acid, caprylic acid, nonanoic acid, decanoic acid, lauric acid, tetradecanoic acid, stearic acid, oleic acid, ricinoleic acid, etc. Preferably, caprylic acid, lauric acid, stearic acid, oleic acid, and ricinoleic acid are used.

The amount of the first carboxylic acid is, for example, 5 to 40% by mass with respect to the zirconium oxide nanoparticles coated with the first carboxylic acid (for the lower limit, preferably 8% by mass or more, more preferably 10% by mass). More preferably, it is 13% by mass or more, and the upper limit is preferably 35% by mass or less, more preferably 30% by mass or less, and further preferably 25% by mass or less. When the zirconium oxide nanoparticles of the present invention are further coated with an organic acid other than the first carboxylic acid described later, the total amount of the first carboxylic acid and the organic acid other than the first carboxylic acid is as described above. If it is in the range of

Note that the zirconium oxide nanoparticles of the present invention are coated with the first carboxylic acid means that the first carboxylic acid is chemically bonded to the zirconium oxide nanoparticles or physically bonded. Meaning that it is coated with the first carboxylic acid and / or the carboxylate derived from the first carboxylic acid.

The zirconium oxide nanoparticles of the present invention are at least one selected from the group M consisting of rare earth elements, Al, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu (hereinafter referred to as elements belonging to the group M). Is sometimes coated as the above-mentioned first carboxylic acid, and such zirconium oxide nanoparticles have not been realized yet. The zirconium oxide nanoparticles of the present invention preferably contain at least one of Y, La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu among the metal elements M. In another preferred embodiment, the metal element M preferably contains at least one selected from the group consisting of rare earth elements, Al and In, and in particular, Y (yttrium), Al, La, Ce and In Preferably, it contains at least one selected from the group consisting of the following (sometimes referred to as a crystal structure stabilizing element), more preferably at least one selected from Y, La and Ce. In these embodiments, zirconium oxide is used. The crystal structure in the crystal is stable. That is, the zirconium oxide nanoparticles of the present invention containing a crystal structure stabilizing element can increase the ratio of tetragonal crystals and / or cubic crystals, and can suppress the reduction of tetragonal crystals when the zirconium oxide nanoparticles are fired. The ratio of the later tetragonal crystal can be increased. The rare earth elements include Sc, Y (yttrium), and lanthanoid elements having atomic number 57 (La) to atomic number 71 (Lu).

The proportion of zirconium contained in the zirconium oxide nanoparticles of the present invention is, for example, 70% by mass or more, preferably 73% by mass or more, more preferably, based on the total of all metal elements contained in the zirconium nanoparticles. It is 75% by mass or more, and particularly preferably 80% by mass or more. Moreover, metal elements other than zirconium and the metal element M may be contained as a metal element contained in the zirconium oxide nanoparticles of the present invention. The metal elements other than zirconium and metal element M are usually metal elements from Group 3 of the periodic table, and the total content thereof is not particularly limited, but is, for example, 5% by mass or less with respect to the total of all metal elements. 3 mass% or less is preferable, 2 mass% or less is more preferable, More preferably, it is 1 mass% or less, and 0 mass% may be sufficient.

Preferred combinations of the metal element M contained in the zirconium oxide nanoparticles of the present invention include (a) at least one selected from the group consisting of rare earth elements and Al, (b) La, Ce, Fe, Co, Sn, At least one selected from the group consisting of Zn, In, Bi, Mn, Ni and Cu, (c) Y, and at least one transition selected from the group consisting of Fe, Co, Mn, Ni and Cu Metal, and the like.

(A) At least one selected from the group consisting of rare earth elements and Al The zirconium oxide nanoparticles of the present invention are a group consisting of rare earth elements and Al among the metal elements M (that is, among elements belonging to the group M). It is also preferable to contain at least one selected from M _a (hereinafter sometimes referred to as metal element M _a ). In this case, it is more preferable that at least one of Y (yttrium), La and Ce is an essential component, more preferably yttrium is an essential component, yttrium is an essential component, and among Al and rare earth elements, One or more of Al, La, Yb, Sc, Ce, and Er (more preferably, one or more of Al, Sc, and Er) may be included.

In particular, when the zirconium oxide nanoparticles of the present invention contain _a metal element Ma, the first carboxylic acid is preferably coated with a secondary carboxylic acid, and the zirconium oxide nanoparticles have at least one of Al and Y. It is more preferable that it contains (especially contains yttrium indispensable) and is coated with a secondary carboxylic acid as the first carboxylic acid.

The content of metal element M _a (Al and rare earth element) (the total content when two or more elements are included) is the ratio of zirconium oxide to the total amount of zirconium oxide and metal element M _a (Al and rare earth element). For example, 0.1 to 20% by mass, preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, particularly preferably 4% by mass or more, and most preferably 5% by mass. That's it. In particular, by setting the content to 3% by mass or more, the ratio of tetragonal crystals after firing can be increased as compared with that before firing.

In the case where zirconium oxide nanoparticles of the present invention contains a metal element M _a, the ratio of zirconium contained in the zirconium oxide nanoparticles of the present invention, the total of all metal elements contained in the zirconium nanoparticles, e.g. 80% by mass or more. Moreover, metal elements other than zirconium, Al, and rare earth elements may be contained as metal elements contained in the zirconium oxide nanoparticles of the present invention. Metal elements other than zirconium, Al, and rare earth elements are usually metal elements from Group 3 and later of the periodic table, and the total content thereof is not particularly limited, but is, for example, 3% by mass or less, preferably 2% by mass or less, More preferably, it is 1 mass% or less, and may be 0 mass%.

Also, if the zirconium oxide nanoparticles of the present invention contains a metal element M _a, the amount of the first carboxylic acid, relative to the zirconium oxide nanoparticles coated with a first carboxylic acid, for example, 5 to 25 mass % (Preferably 10% by mass or more, more preferably 13% by mass or more).

(B) At least one selected from the group M _b consisting of La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni, and Cu. , La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni, and Cu, at least one metal element selected from the group M _b (hereinafter sometimes referred to as metal element M _b ) (However, in this case, yttrium is not included. In addition to yttrium, it may not include Al, La and Ce, and may not include Al and rare earth elements.) The total content of the metal element M _b is preferably 0.1 to 20 mass% in a ratio to the total content of the metal element M _b and zirconium, and more preferably 1 to 15 mass%.

More specifically, the La content is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total of La and zirconium.
The Ce content is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total of Ce and zirconium.
The Fe content is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, based on the total of Fe and zirconium.
The Co content is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total of Co and zirconium.
The Sn content is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total of Sn and zirconium.
The content of Zn is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass with respect to the total of Zn and zirconium.
The content of In is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass with respect to the total of In and zirconium.
The content of Bi is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total of Bi and zirconium.
The Mn content is preferably from 0.1 to 15% by mass, more preferably from 0.5 to 10% by mass, based on the total of Mn and zirconium.
The content of Ni is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass with respect to the total of Ni and zirconium.
The Cu content is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, based on the total of Cu and zirconium.

The metal element M _b exists as a complex oxide of zirconium and the metal element M _b in the zirconium oxide nanoparticles. Among these metal elements M _b , lanthanum, cerium and indium in particular have the effect of stabilizing zirconium oxide as yttrium since tetragonal zirconium oxide was mainly detected even after firing as described later.

In the case where zirconium oxide nanoparticles of the present invention comprises a metal element M _b, the proportion of zirconium contained in the zirconium oxide nanoparticles, based on the combined total of all the metal elements contained in the zirconium nanoparticles, for example 70 wt% or more Preferably, it is 73 mass% or more, More preferably, it is 75 mass% or more. Further, as the metal element contained in the zirconium oxide nanoparticles of the present invention, other metals other than the above metal element M _b (La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu) An element may be included (however, yttrium is not included), and such other metal element is usually a metal element from Group 3 of the periodic table. The total amount of other metal elements is, for example, 5% by mass or less, more preferably 2% by mass or less, or 0% by mass with respect to the total of all metal elements contained in the zirconium nanoparticles. .

When the zirconium oxide nanoparticles of the present invention contain _Mb group elements, the amount of the first carboxylic acid is, for example, 5 to 40% by mass with respect to the zirconium oxide nanoparticles coated with the first carboxylic acid ( It is preferably 8 to 35% by mass, more preferably 10 to 30% by mass).

Moreover, translucent, toughness, ceramic properties such as strength for zirconium oxide nanoparticles may comprise a metal element M _b, a ceramic material obtained by firing the zirconium oxide nanoparticles are uniform particle size of the present invention Is good.

(C) At least one transition metal selected from the group consisting of Y and further Fe, Co, Mn, Ni, and Cu. The zirconium oxide nanoparticles of the present invention include Fe, Co together with yttrium in the metal element M. It is also preferable that at least one transition metal selected from the group consisting of Mn, Ni and Cu is included. In this embodiment, the zirconium oxide nanoparticles contain yttrium (for example, contained as yttria), and the crystal structure of the zirconium oxide crystal is stable. That is, the ratio of tetragonal crystals and / or cubic crystals in the zirconium oxide nanoparticles of the present invention can be increased, and reduction of tetragonal crystals and / or cubic crystals when the zirconium oxide nanoparticles are fired can be suppressed. The ratio of tetragonal crystals and / or cubic crystals can be increased. Furthermore, in the present invention, since the zirconium oxide nanoparticles contain a transition metal, the ceramics obtained by firing the nanoparticles are colored, and the zirconium oxide nanoparticles themselves contain a transition metal. Compared with the case where the oxide of the transition metal and the transition metal are separately prepared, mixed, and fired, the color of the sintered body is reduced not only uniformly but also due to grain boundaries with other oxides. It becomes possible to prevent.

The content of yttrium is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass with respect to the total mass of zirconium, yttrium and the above-mentioned transition metal in the zirconium oxide nanoparticles. More preferably, it is 1.5 to 15% by mass. If the amount of yttrium is too small, the stabilization effect may not be sufficiently obtained, and if the amount of yttrium is too large, the original performance of zirconium oxide may not be sufficiently obtained.

The above-mentioned transition metal content (the total content when plural types are included) is 0.05 to 2% by mass in terms of the total mass of zirconium, yttrium and transition metal in the zirconium oxide nanoparticles, More preferred is 0.1 to 1% by mass, and further more preferred is 0.15 to 0.6% by mass. If the amount of the transition metal is too small, the effect of the transition metal may not be sufficiently exhibited, and the coloring and doping effects after firing are not sufficiently exhibited. On the other hand, if the amount of transition metal is too large, the stabilizing effect of yttrium is lowered, and the hardness and toughness after firing are affected.

In addition, when the zirconium oxide nanoparticles of the present invention contain at least one transition metal described above together with yttrium, the proportion of zirconium contained in the zirconium oxide nanoparticles is based on the total of all metal elements contained in the zirconium nanoparticles. For example, it is 65% by mass or more, preferably 68% by mass or more, and more preferably 70% by mass or more. Further, as the metal element contained in the zirconium oxide nanoparticles of the present invention, other metal elements other than yttrium and transition metals may be contained. It is a metal element. The total amount of other metal elements is, for example, 3% by mass or less, more preferably 2% by mass or less, and may be 0% by mass with respect to the total of all metal elements contained in the zirconium nanoparticles. .

When the zirconium oxide nanoparticles of the present invention contain at least one of the transition metals described above together with yttrium, the amount of the first carboxylic acid is, for example, relative to the zirconium oxide nanoparticles coated with the first carboxylic acid, It is 5 to 40% by mass (preferably 8 to 35% by mass, more preferably 10 to 30% by mass).

The zirconium oxide particles of the present invention are obtained by coating the first carboxylic acid obtained after the hydrothermal synthesis reaction with an organic acid other than the first carboxylic acid by subjecting the surface treatment to room temperature or heating. The surface may be modified with a silane coupling agent, a surfactant, an organic phosphorus compound, an organic sulfur compound, or the like. By subjecting the nanoparticles obtained first to surface treatment again, it becomes possible to control the mixing property with other substances, the moldability, etc., and it can be applied to various uses. Preferred organic acids, silane coupling agents, surfactants, organic phosphorus compounds, and organic sulfur compounds are described below.

<Organic acid>
As the organic acid, a carboxylic acid compound having a carboxyl group other than the first carboxylic acid is preferably used. Since the carboxylic acid compound is chemically bonded to the zirconium oxide nanoparticles or forms a carboxylic acid or a salt thereof together with a hydrogen atom or a cationic atom and adheres to the zirconium oxide nanoparticles, the term “coating” in the present invention refers to a carboxylic acid compound. It includes both the state in which the acid compound is chemically bonded to zirconium oxide and the state in which the carboxylic acid compound is physically attached to zirconium oxide.

The carboxylic acid compound having a carboxyl group other than the first carboxylic acid can be freely selected depending on the dispersibility in the solvent and the properties of the material other than the zirconium oxide nanoparticles, but (meth) acrylic acids and esters A carboxylic acid having one or more substituents selected from the group consisting of a group, an ether group, a hydroxyl group, an amino group, an amide group, a thioester group, a thioether group, a carbonate group, a urethane group, and a urea group; Hydrocarbons having one or more (preferably one) carboxylic acid groups such as linear carboxylic acid, branched carboxylic acid, cyclic carboxylic acid, or aromatic carboxylic acid are preferably employed.

Specific examples of such carboxylic acid compounds include (meth) acrylic acids (for example, (meth) acryloyloxy C _1-6 alkyl carboxylic acids such as acrylic acid, methacrylic acid, 3-acryloyloxypropionic acid, etc.); C _3-9 Half esters of aliphatic dicarboxylic acid with (meth) acryloyloxy C _1-6 alkyl alcohol (for example, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, etc.), C _5-10 fatty acid Half esters of cyclic dicarboxylic acids with (meth) acryloyloxy C _1-6 alkyl alcohols (for example, 2-acryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, etc.), C _8-14 aromatic dicarboxylic acids (meth) acryloyloxy C _1-6 half by alkyl alcohol Carboxylic acids having ester groups such as stealth (eg 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid); pivalic acid, 2,2-dimethylbutyric acid, 2,2-dimethylvaleric acid Branched carboxylic acids such as 2,2-diethylbutyric acid and neodecanoic acid; cyclic carboxylic acids such as naphthenic acid and cyclohexanedicarboxylic acid; carboxylic acids containing ether groups (methoxyacetic acid, ethoxyacetic acid, etc.); containing hydroxyl groups Carboxylic acids (such as lactic acid and hydroxypropionic acid), carboxylic acids having an amino group (such as amino acids such as glycine, alanine, and cysteine).

The addition amount of the carboxylic acid compound is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the zirconium oxide nanoparticles.

<Silane coupling agent>
As the silane coupling agent, a compound having a hydrolyzable group —Si—OR ⁹ (where R ⁹ is a methyl group or an ethyl group) is preferable. As such a silane coupling agent, a silane coupling agent having a functional group, an alkoxysilane, and the like can be exemplified.

As a silane coupling agent having a functional group, the following formula (1):
[X— (CH ₂ ) _m ] _4-n —Si— (OR ⁹ ) _n (1)
(Wherein X is a functional group, R ⁹ is the same as above, m is an integer of 0 to 4, and n is an integer of 1 to 3).

Examples of X include a vinyl group, an amino group, a (meth) acryloxy group, a mercapto group, and a glycidoxy group. Specific examples of the silane coupling agent include, for example, a silane coupling agent having a vinyl functional group X such as vinyltrimethoxysilane and vinyltriethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltri Silane coupling in which the functional group X is an amino group, such as ethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltrimethoxysilane Agent: Functionality such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane Group X is (meta Silane coupling agent which is acryloxy group; Silane coupling agent whose functional group X is mercapto group such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; 2- (3,4-epoxycyclohexyl) ethyl Functional groups X such as trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane And a silane coupling agent which is a glycidoxy group.

Examples of the alkoxysilane include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxy. Alkyl group-containing alkoxysilane in which an alkyl group such as silane is directly bonded to the silicon atom of alkoxysilane; an aromatic ring such as phenyltrimethoxysilane, diphenyldimethoxysilane, p-styryltrimethoxysilane, etc. directly on the silicon atom of alkoxysilane And aryl group-containing alkoxysilanes bonded to each other.

As the silane coupling agent, a silane coupling agent whose functional group X is a (meth) acryloxy group and an alkyl group-containing alkoxysilane are preferable, and 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyl are particularly preferable. Trimethoxysilane, hexyltrimethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane.

The silane coupling agent may be used alone or in combination of two or more. The amount (covering amount) of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the entire zirconium oxide nanoparticles.

<Surfactant>
The surfactant can improve the transparency and dispersibility of the composition. Furthermore, the viscosity of the composition can be reduced. As the surfactant, an anionic surfactant, a cationic surfactant, an ionic surfactant such as an amphoteric surfactant, or a nonionic surfactant is preferably used. Examples of the activator include fatty acid sodium such as sodium oleate, sodium stearate and sodium laurate, fatty acid potassium such as fatty acid potassium and sodium fatty acid ester sulfonate, phosphoric acid such as sodium alkyl phosphate ester, and alpha olein sulfone. Examples of cation surfactants include olefins such as sodium acid, alcohols such as sodium alkyl sulfate, and alkylbenzenes. Examples of the cationic surfactant include alkyl methyl ammonium chloride, alkyl dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, and alkyl dichloride. Examples of the zwitterionic ammonium include zwitterionic surfactants such as carboxylic acid-based surfactants such as alkylaminocarboxylates, and phosphoric ester-based surfactants such as phosphobetaine. Examples include fatty acid series such as oxyethylene laurin fatty acid ester and polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, and fatty acid alkanolamide. The surfactant is preferably added in an amount of 0.1% by mass to 5% by mass with respect to 100% by mass of all components of the composition.

<Organic phosphorus compounds>
As an organic phosphorus compound, for example, the following formula:

(In the above formula, p ¹ and p ² are each preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30, more preferably 4 to 15. Also, p ¹ + p ² is preferably 1 to 100, more preferably 1 to 50, and still more preferably 1 to 30), and phosphoric acid diesters having the same substituents. It is done.

Also, the following formula:

[In the above formula, a is 1 or 2, and A is a substituent group represented by the following formula:

(In the above formula, p ¹ , p ² and p ⁵ are each preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30, and more preferably 4 to 15.) p ¹ + p ² + p ⁵ is preferably 1 to 100, more preferably 1 to 50, and further preferably 1 to 30. r, r ² and r ³ are preferably 1 to 100, more preferably 1 And more preferably 1 to 20. R ⁴ and R ¹⁰ are each a divalent hydrocarbon group having 1 to 18 carbon atoms or a divalent aromatic-containing hydrocarbon group having 6 to 30 carbon atoms. * Represents a binding site with a phosphorus atom.) At least one selected from the group consisting of a phosphoric acid monoester or a phosphoric acid diester represented by the following formula:

[In the above formula, a is 1 or 2, and A is a substituent group represented by the following formula:

(Wherein p ¹ is preferably 1 to 100, more preferably 1 to 50, and still more preferably 1 to 30).] (For example, formula:

(Wherein p ¹ is preferably 1 to 100, more preferably 1 to 50, and still more preferably 1 to 30)) or the following formula:

Examples thereof include various phosphate compounds or phosphate esters.

In the present invention, two or more organic phosphorus compounds having different structures such as phosphoric acid monoesters and phosphoric acid diesters or salts thereof may be used alone or in combination.

Examples of the organophosphorus compound described above include Newcol 1000-FCP (manufactured by Nippon Emulsifier Co., Ltd.), Antox EHD-400 (manufactured by Nippon Emulsifier Co., Ltd.), Phoslex series (manufactured by SC Organic Chemical Co., Ltd.), Kyoeisha Chemical Co., Ltd.), Light Acrylate P-1M (Kyoeisha Chemical Co., Ltd.), TEGO (registered trademark) Dispers 651, 655, 656 (Evonik Co., Ltd.), DISPERBYK-110, 111 (Bicchemy Japan Co., Ltd.), KAYAMERPM-2 Commercially available phosphate esters such as KAYAMERPM-21 (manufactured by Nippon Kayaku Co., Ltd.) can be used as appropriate.

The amount of the organic phosphorus compound is about 0.5 to 10 parts by mass with respect to 100 parts by mass of the zirconium oxide nanoparticle-containing composition of the present invention.

<Organic sulfur compounds>
As the organic sulfur compound, the following formula (2):

[B represents a substituent represented by the following formula (b1) or a substituent containing at least one linking group represented by the following formula (b2) in the substituent represented by the following formula (b1). . In addition, when B has a connecting group represented by the following formula (b2), the following formula (b2) is bonded to a sulfur atom on the oxygen atom side.

Wherein R ⁵ represents a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms, a (meth) acryloyl group, or an aromatic hydrocarbon group having 6 to 100 carbon atoms, and t is 0 or 1. .)

(Wherein, R ^6, R ^7, R ⁸ is a divalent hydrocarbon group or a divalent aromatic-containing hydrocarbon group having 6 to 30 carbon atoms having 1 to 18 carbon atoms, wherein R ^6, The hydrogen atoms constituting R ⁷ and R ⁸ may be substituted with an ether group, p, q and r each represent an integer molar ratio to 1 mol of the (b1) unit, p + q + r = 1 to 200, p = 1 to 200, q = 1 to 200, r = 1 to 200))] is preferably used.

Of R ^{5 in} the formula (b1), examples of the saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms include a methyl group, an ethyl group, a propyl group (such as an n-propyl group and an iso-propyl group), and a butyl group. (N-butyl group, tert-butyl group, sec-butyl group, etc.), pentyl group (n-pentyl group, isopentyl group, neopentyl group, etc.), hexyl group (n-hexyl group, 2-methylpentyl group, 3- Methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, etc.), heptyl group (n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl group, etc.), octyl group (n-octyl group, methyl) Heptyl, dimethylhexyl, 2-ethylhexyl, 3-ethylhexyl, trimethylpentyl, 3-ethyl-2-methylpentyl, 2-ethyl-3-methylpentyl, 2,2,3,3-tetra Methylbutyl group), nonyl group (n-nonyl group, methyloctyl group, dimethylheptyl group, 3-ethylheptyl group, 4-ethylheptyl group, trimethylhexyl group, 3,3-diethylpentyl group, etc.), decyl group Linear or branched alkyl groups such as isodecyl group, undecyl group, dodecyl group, tridecyl group, stearyl group, isostearyl group; vinyl group, propenyl group (allyl group, 1-methylvinyl group, etc.), butenyl group ( 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2-methylallyl group, etc.), And linear or branched alkenyl groups such as nonenyl group (such as 1,1-dimethylallyl group), nonenyl group, decenyl group, octadecenyl group, palmitolyl group, oleyl group, linoyl group, linoleyl group, and the like. The number of carbon atoms of the hydrocarbon group is more preferably 1 to 25, still more preferably 1 to 18, and particularly preferably 1 to 12. Among the above examples, a linear or branched alkyl group having 1 to 10 carbon atoms or a linear or branched alkenyl group having 2 to 4 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group ( n-propyl group, iso-propyl group, etc.), butyl group (n-butyl group, tert-butyl group, sec-butyl group etc.), octyl group (n-octyl group, methylheptyl group, dimethylhexyl group, 2- Ethylhexyl group, 3-ethylhexyl group, etc.), decyl group, vinyl group, propenyl group (allyl group, 1-methylvinyl group etc.), butenyl group (1-methylallyl group, 2-methylallyl group etc.), most preferably Methyl group, ethyl group, octyl group, decyl group, and 1-methylvinyl group.
Further, the hydrogen atom of the saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms may be substituted with an aromatic hydrocarbon group having 6 to 100 carbon atoms described later. Examples of the aromatic hydrocarbon group having 6 to 100 carbon atoms used as a substituent for the saturated or unsaturated hydrocarbon group include a phenyl group and a naphthyl group, and more preferably a phenyl group. Examples of the saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms that is substituted with an aromatic-containing hydrocarbon group having 6 to 100 carbon atoms include the following substituents (* represents an adjacent oxygen atom) Indicates the binding site).

The (meth) acryloyl group according to R ⁵ is a generic name for a methacryloyl group represented by CH ₂ ═C (CH ₃ ) —CO— * and an acryloyl group represented by CH ₂ ═CH—CO— *. .

The aromatic hydrocarbon group having 6 to 100 carbon atoms in R ⁵ preferably has 1 to 5 rings (more preferably 1 to 3 rings), and in the case of 2 or more rings, it may be condensed. In the case of two or more rings, at least one ring is an aromatic ring. When there are two or more aromatic rings, these may be directly bonded by sigma bonds in addition to the case where they are condensed.
Specific examples of such aromatic-containing hydrocarbon groups include a phenyl group, a naphthyl group, a pentarenyl group, an indenyl group, an anthracenyl group, a phenanthryl group, a fluorenyl group, a biphenylyl group, and the like, and a phenyl group or a naphthyl group is preferable, More preferably, it is a phenyl group. In addition, hydrogen atoms of these aromatic-containing hydrocarbon groups (such as aryl groups) are substituted with substituents such as alkyl groups having 1 to 50 carbon atoms, alkenyl groups having 1 to 50 carbon atoms, and aralkyl groups having 7 to 50 carbon atoms. May be.

The alkyl group having 1 to 50 carbon atoms used as a substituent for the aromatic-containing hydrocarbon group is preferably, for example, a linear or branched alkyl group, more preferably an alkyl group having 1 to 25 carbon atoms, More preferred are alkyl groups having 5 to 15 carbon atoms, and particularly preferred are nonyl group, decyl group, isodecyl group, undecyl group and dodecyl group.
The alkenyl group having 1 to 50 carbon atoms used as a substituent for the aromatic-containing hydrocarbon group is preferably, for example, a linear or branched alkenyl group, and more preferably a linear or branched alkenyl group having 2 to 4 carbon atoms. And more preferably a vinyl group, a propenyl group (allyl group, 1-methylvinyl group, etc.), a butenyl group (1-butenyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2 -Methylallyl group).
Examples of the aralkyl group having 7 to 50 carbon atoms used as a substituent of the aromatic-containing hydrocarbon group include a benzyl group, a phenethyl group (for example, a 1-phenethyl group, a 2-phenethyl group), a phenylpropyl group, A phenylbutyl group, a phenylpentyl group, etc. are mentioned. Among them, more preferred are a benzyl group and a phenethyl group, still more preferred is a phenethyl group, and particularly preferred is a 2-phenethyl group.
Examples of the aromatic hydrocarbon group to which an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, and an aralkyl group having 7 to 50 carbon atoms are bonded include the following.

　中でもＲ⁵としては、炭素数１～５０の直鎖又は分岐のアルキル基、炭素数２～５０の直鎖又は分岐のアルケニル基、（メタ）アクリロイル基、もしくは炭素数６～２０の芳香族含有炭化水素基が好ましく、炭素数１～３０の直鎖又は分岐のアルキル基、炭素数２～３０の直鎖又は分岐のアルケニル基、もしくは炭素数６～２０の芳香族含有炭化水素基がより好ましく、炭素数１～２５の直鎖又は分岐のアルキル基、炭素数２～２５の直鎖又は分岐のアルケニル基、もしくは炭素数６～１０の芳香族含有炭化水素基が更に好ましい。特に好ましいＲ⁵は、ビニル基、プロペニル基（アリル基、１－メチルビニル基など）、ブテニル基（１－メチルアリル基、２－メチルアリル基など）、置換されていてもよいフェニル基であり、より好ましくはビニル基、プロペニル基、ブテニル基、下記式で例示される置換基である。

Among them, R ⁵ includes a linear or branched alkyl group having 1 to 50 carbon atoms, a linear or branched alkenyl group having 2 to 50 carbon atoms, a (meth) acryloyl group, or an aromatic group having 6 to 20 carbon atoms. A hydrocarbon group is preferable, and a linear or branched alkyl group having 1 to 30 carbon atoms, a linear or branched alkenyl group having 2 to 30 carbon atoms, or an aromatic-containing hydrocarbon group having 6 to 20 carbon atoms is more preferable. Further, a linear or branched alkyl group having 1 to 25 carbon atoms, a linear or branched alkenyl group having 2 to 25 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms is more preferable. Particularly preferred R ⁵ is a vinyl group, a propenyl group (such as an allyl group or a 1-methylvinyl group), a butenyl group (such as a 1-methylallyl group or a 2-methylallyl group), or an optionally substituted phenyl group. A vinyl group, a propenyl group, a butenyl group, and a substituent exemplified by the following formula are preferred.

Further, p, q, and r each represent an integer molar ratio with respect to 1 mole of the (b1) unit, and p + q + r is preferably 1 to 100, p = 1 to 50, q = 1 to 50, and r = 1 to 50. . T is preferably 0.

Substituent B has the following formula (a6):

It is particularly preferred from the viewpoint of dispersibility / availability that either or both of the linking groups represented by (wherein p ¹ and p ² are integer molar ratios relative to 1 mol of (b1) unit) are included. p ¹ and p ² are each preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and most preferably 1 to 30. Further, p ¹ + p ² is preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and most preferably 1 to 30.

Examples of such organic sulfur compounds include benzenesulfonic acid, dodecylbenzenesulfonic acid, methylsulfonic acid, ethylsulfonic acid, and various organic sulfur compounds represented by the following formulas.

 

 

(In the formula, p ¹ is the same as above, and R is an optional substituent.)

The crystal structure of the zirconium oxide nanoparticles of the present invention is cubic, tetragonal or monoclinic, and the total of the tetragonal and cubic crystals is preferably 80% or more of the entire crystal structure. The total proportion of tetragonal crystals and cubic crystals is preferably 85% or more, more preferably 90% or more. Tetragonal crystal alone or cubic crystal alone may be used. Further, particularly when the zirconium oxide nanoparticles of the present invention contain Al, rare earth elements, or In, tetragonal crystals and / or cubic crystals are stable, and the tetragonal crystals of the ceramic material obtained by firing are obtained. And / or the proportion of cubic crystals is also high. The ratio of tetragonal crystals and / or cubic crystals of the ceramic material obtained by firing the zirconium oxide nanoparticles of the present invention is, for example, 25% or more, preferably 50% or more, more preferably the total of tetragonal crystals and cubic crystals. Is 90% or more. Moreover, the reduction | decrease of the tetragonal crystal and / or cubic after baking is suppressed. The amount of change in the total ratio of tetragonal crystals and cubic crystals before and after firing is preferably 70% or less, more preferably 30% or less, and even more preferably 10% or less with respect to the total ratio of tetragonal crystals and cubic crystals before firing. Yes, most preferably 5% or less.

Examples of the shape of the zirconium oxide nanoparticles include a spherical shape, a granular shape, an elliptical spherical shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, a needle shape, a columnar shape, a rod shape, a cylindrical shape, a flake shape, a plate shape, and a flake shape. Considering the dispersibility in a solvent and the physical strength after sintering, the shape is preferably spherical, granular, columnar or the like.

The crystallite diameter of the zirconium oxide nanoparticles calculated by X-ray diffraction analysis is preferably 30 nm or less, and more preferably 20 nm or less. By doing in this way, the transparency of the composition containing a zirconium oxide nanoparticle can be improved. Moreover, reduction of the calcination temperature of the said particle | grain, improvement of the transparency of a baked body, etc. can be anticipated collectively. The crystallite diameter is more preferably 20 nm or less, still more preferably 15 nm or less, and particularly preferably 10 nm or less. The lower limit of the crystallite diameter is usually about 1 nm.

The particle diameter of the zirconium oxide nanoparticles can be evaluated by an average particle diameter obtained by processing images obtained by various electron microscopes, and the average particle diameter (average primary particle diameter) is preferably 50 nm or less. By doing in this way, the transparency of the composition containing a zirconium oxide nanoparticle can be improved. The average primary particle diameter is more preferably 30 nm or less, and further preferably 20 nm or less. The lower limit of the average primary particle size is usually about 1 nm (particularly about 5 nm).

The average particle size was randomly increased by expanding the zirconium oxide nanoparticles with a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-SEM), etc. It can be determined by selecting 100 particles, measuring the length in the major axis direction, and calculating the arithmetic average thereof.

Next, the manufacturing method of the zirconium oxide nanoparticle of this invention is demonstrated. The zirconium oxide nanoparticles of the present invention are coated with the first carboxylic acid by hydrothermal reaction of the zirconium component, the metal element M component, and the first carboxylic acid, and the zirconium oxide nanoparticle containing the metal element M is contained. Particles can be obtained. As the zirconium component, a zirconium raw material composed of (preferably combined) a first carboxylic acid and zirconium or a zirconium-containing compound can be used. Such a zirconium raw material is a first carboxylic acid. It can also be said to be an ingredient. Further, as the metal element M component, a raw material material of the metal element M composed of (preferably a combination) of the first carboxylic acid and at least one of the metal element M and the metal element M-containing compound is used. Such a second metal source material can also be said to be a first carboxylic acid component. At this time, the first carboxylic acid contained in the zirconium component and the second metal component may be the same or different, and a plurality of types may be used. In the present invention, since the specific first carboxylic acid is used, zirconium oxide nanoparticles can be obtained by hydrothermal synthesis without using MgSO ₄ as used in Non-Patent Document 1 described above. it can.

Specific examples of the zirconium raw material include (i) a salt of a first carboxylic acid and a zirconium oxide precursor, (ii) a zirconium salt of the first carboxylic acid, and (iii) a first carboxylic acid and an oxidation. Examples thereof include at least one selected from zirconium precursors.

Examples of the zirconium oxide precursor include zirconium hydroxide, chloride, oxychloride, acetate, oxyacetate, oxynitrate, sulfate, carbonate, alkoxide and the like. That is, zirconium alkoxides such as zirconium hydroxide, zirconium chloride, zirconium oxychloride, zirconium acetate, zirconium oxyacetate, zirconium oxynitrate, zirconium sulfate, zirconium carbonate, and tetrabutoxyzirconium.

Hereinafter, as the zirconium oxide precursor, a zirconium oxide precursor such as oxychloride of zirconium and nitrates such as oxynitrate, which is suitable for use as a raw material, a zirconium oxide precursor that is highly water-soluble and corrosive is preferable ( The case of i) will be described in detail. The salt is not only a single compound composed of a stoichiometric ratio of carboxylic acid and zirconium oxide precursor, but also a composite salt or a composition containing an unreacted carboxylic acid or zirconium oxide precursor. There may be.

In the above (i), the salt of the first carboxylic acid and the zirconium oxide precursor was neutralized with an alkali metal and / or alkaline earth metal in a range of 0.1 to 0.8. A salt of the first carboxylic acid and zirconium obtained by reacting the carboxylate-containing composition derived from the first carboxylic acid with the zirconium oxide precursor is preferable.

The neutralization degree is preferably 0.1 to 0.8, more preferably 0.2 to 0.7. If it is less than 0.1, the first carboxylic acid compound has low solubility, so that the salt may not be sufficiently formed. If it exceeds 0.8, a large amount of white precipitate presumed to be a hydroxide of zirconium is formed. In some cases, the yield of the coated zirconium oxide particles decreases. The alkali metal and alkaline earth metal used to obtain the carboxylate-containing composition may be any, but a metal that forms a highly water-soluble carboxylate is preferable, and alkali metals, particularly sodium and potassium are preferred. Is preferred.

The ratio of the carboxylate-containing composition to the zirconium oxide precursor is preferably 1 to 20 moles of carboxyl groups, more preferably 1.2 to 18 moles per mole of zirconium oxide precursor. 1.5 to 15 mol is more preferable.
In order to react the carboxylate-containing composition with the zirconium oxide precursor, it is preferable to mix aqueous solutions or an aqueous solution and an organic solvent. The reaction temperature is not particularly limited as long as the aqueous solution can be maintained, but is preferably from room temperature to 100 ° C, more preferably from 40 ° C to 80 ° C.

The salt obtained by reacting the carboxylate-containing composition with the zirconium oxide precursor may be subjected to a hydrothermal reaction as it is, but insoluble by-products are removed by filtration, liquid separation, or the like. Is preferred.

Next, the case (ii) will be described in detail.
In the embodiment (ii), a zirconium salt of the first carboxylic acid prepared in advance is used. There is an advantage that it can be subjected to a hydrothermal reaction without going through the complicated steps as described above. However, since the compounds that can be easily obtained are limited, the target zirconium oxide particles coated with an organic group may not be obtained.

Examples of the zirconium salt that can be used in the embodiment of (ii) include zirconium octoate, zirconium 2-ethylhexanoate, zirconium stearate, zirconium laurate, zirconium naphthenate, zirconium oleate, zirconium ricinoleate and the like. I can do it. When the purity of the zirconium salt is low, it may be used after purification, but a commercially available product or a salt prepared in advance can be directly subjected to a hydrothermal reaction.

The zirconium oxide precursor that can be used in (iii) is the same as the zirconium oxide precursor described above. In the case of (iii), the zirconium oxide precursor is preferably zirconium carbonate. The ratio of the carboxylic acid to the zirconium oxide precursor is preferably 0.5 mol to 10 mol, more preferably 1 mol to 8 mol, based on 1 mol of the zirconium oxide precursor. Preferably, the amount is 1.2 mol to 5 mol. The carboxylic acid and the zirconium oxide precursor may be subjected to a hydrothermal reaction as they are, or may be reacted in advance before the hydrothermal reaction. In order to make it react before a hydrothermal reaction, it is preferable to make carboxylic acid and a zirconium oxide precursor react in a slurry in an organic solvent. At that time, it is preferable to carry out the reaction while removing water produced during the reaction, also in terms of improving the reaction rate and yield. In order to perform the reaction while extracting water during the reaction, it is preferable to use a solvent having a boiling point higher than that of water as the reaction solvent, and more preferably a solvent used in the hydrothermal reaction described later. Moreover, 70 degreeC or more is preferable and, as for reaction temperature, 80 degreeC or more is more preferable so that water can be extracted. The upper limit of the reaction temperature is 180 ° C. or lower, and more preferably 150 ° C. or lower. If the temperature is too high, side reactions may proceed and decomposition of the carboxylic acid may occur. If water cannot be taken out during the reaction, the reaction can be carried out by lowering the reaction pressure to lower the boiling point of water.

Specifically, as the metal element M raw material, (i) a salt of the first carboxylic acid and a precursor of the metal element M, (ii) a salt of the metal element M of the first carboxylic acid, and (iii) Examples include at least one selected from the first carboxylic acid and the precursor of the metal element M. Preferred embodiments (i) to (iii) are the same as the preferred embodiments (i) to (iii) in the zirconium raw material.

More specifically, when the zirconium oxide nanoparticles of the present invention contain at least one (metal element M _a ) selected from the group consisting of the above-mentioned (a) rare earth elements and Al among the metal elements M, Specifically, as the Al or rare earth element raw material, (i) a salt of a first carboxylic acid and a precursor such as a rare earth oxide, (ii) a salt of a rare earth element of the first carboxylic acid, and ( iii) At least one selected from precursors such as the first carboxylic acid and rare earth oxide.

The zirconium oxide nanoparticles of the present invention are at least one selected from the group consisting of (b) La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu described above among the metal elements M ( When the metal element M _b ) is contained, as a raw material of the metal element M _b , specifically, (i) a salt of the first carboxylic acid and an oxide precursor of the metal element M _b , (ii ) salt of a metal element M _b of the first carboxylic acid, and (iii) an oxide precursor of the first carboxylic acid and the metal element M _b, at least one or more can be mentioned are chosen from.

When the zirconium oxide nanoparticles of the present invention contain Y as described above of the metal element M and at least one transition metal selected from the group consisting of Fe, Co, Mn, Ni and Cu, the yttrium raw material Specifically, (i) a salt of a first carboxylic acid and an yttrium oxide precursor, (ii) an yttrium salt of the first carboxylic acid, and (iii) a first carboxylic acid and an yttrium oxide precursor And at least one selected from the group consisting of

Specifically, as the transition metal source material, (i) a salt of a first carboxylic acid and a transition metal oxide precursor, (ii) a transition metal salt of the first carboxylic acid, and (iii) a first Examples thereof include at least one selected from carboxylic acids and transition metal oxide precursors.

At least one of the above (i) to (iii) for the zirconium component and at least one of the above (i) to (iii) for the metal element M component are preferably mixed in the presence of water. At this time, by performing under heating or under reduced pressure, low boiling point compounds contained in the zirconium oxide precursor such as ammonia and acetic acid can be driven out of the system, and the pressure increase in the hydrothermal reaction in the next step is suppressed. Therefore, it is preferable. In addition, you may perform the said reaction in the solution which added the below-mentioned organic solvent.

Subsequently, the hydrothermal reaction will be described.
Zirconium oxide nanoparticle composition by subjecting at least one of (i) to (iii) for the zirconium component and at least one of (i) to (iii) for the metal element M component to a hydrothermal reaction Is obtained. If the above (i) to (iii) alone are high in viscosity and the hydrothermal reaction does not proceed efficiently, it is preferable to add an organic solvent exhibiting good solubility in the above (i) to (iii) . In order to obtain the zirconium oxide nanoparticles of the present invention, a zirconium salt of the first carboxylic acid and a salt of the metal element M of the first carboxylic acid are used as the zirconium component and the metal element M component, respectively. It is preferable to use the embodiment (ii) for any of the metal element M components. However, when there is at least one component that is difficult to use the aspect (ii) for the zirconium component and the metal element M component, there may of course be a component used in the aspect (i) or (iii) In such a case, (ii) and (i) only, (ii) and (iii) only, (i) only, and (iii) only as aspects of the raw material used as the zirconium component and metal element M component Either is preferable. When both the zirconium component and the metal element M component are used in the form (iii), the zirconium oxide precursor, the oxide precursor of the metal element M and the first carboxylic acid are mixed before the hydrothermal reaction. A raw material containing both zirconium and the metal element M may be synthesized in advance, and by doing so, the number of synthesis steps can be reduced.

As the organic solvent, hydrocarbons, ketones, ethers, alcohols and the like can be used. Since there is a possibility that the reaction does not proceed sufficiently with a solvent that is vaporized during a hydrothermal reaction, an organic solvent having a boiling point of 120 ° C. or higher under normal pressure is preferable, 140 ° C. or higher is more preferable, and 150 ° C. or higher is even more preferable. Specifically, decane, dodecane, tetradecane, mesitylene, pseudocumene, mineral oil, octanol, decanol, cyclohexanol, terpineol, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butane Examples include diol, 2,3-butanediol, hexanediol, glycerin, methanetrimethylol, toluene, xylene, trimethylbenzene, dimethylformamide (DMF), dimethylsulfoxide (DMSO) and the like, and dodecane, tetradecane, and trimethylbenzene are preferable.

When separated into two layers by adding the organic solvent, a surfactant or the like may be added to obtain a homogeneous phase state or a suspension emulsified state, but usually the two layers are subjected to a hydrothermal reaction. I can do it. The composition may contain a sufficient amount of water derived from the raw material, but if there is no or little water contained in the raw material, add water before subjecting it to a hydrothermal reaction. There is a need.

The amount of water present in the hydrothermal reaction system is the number of moles of water relative to the number of moles of the zirconium oxide precursor or salted salt containing zirconium (hereinafter referred to as zirconium oxide precursor) present in the system (number of moles of water / The number of moles of the zirconium oxide precursor and the like is preferably 1/1 or more, more preferably 4/1 or more, still more preferably 8/1 or more, preferably 100/1 or less, more preferably 50/1. Or less, more preferably 30/1 or less. If it is less than 1/1, the hydrothermal reaction may take a long time, and the obtained zirconium oxide particles may have a large particle size. On the other hand, if it exceeds 100/1, there is no particular problem except that productivity is lowered because there are few zirconium oxide precursors and the like present in the system.

The preferred range of the number of moles of water / the number of moles of the zirconium oxide precursor, etc. is as follows.
(A) When the metal element M contains at least one selected from the group consisting of rare earth elements and Al, 4/1 to 100/1 is preferable, and 8/1 to 50/1 is more preferable.
(B) Among metal elements M, when containing at least one selected from the group consisting of La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, Ni and Cu, 1/1 to 50/1 is preferable, and 4/1 to 30/1 is more preferable.
(C) In the case where the metal element M contains Y and at least one transition metal selected from the group consisting of Fe, Co, Mn, Ni and Cu, 1/1 to 50/1 is preferable. 4/1 to 30/1 is more preferable.

The hydrothermal reaction is preferably performed at a pressure of 2 MPaG (gauge pressure) or less. Although the reaction proceeds even at 2 MPaG or more, the reaction apparatus becomes expensive, which is not industrially preferable. On the other hand, if the pressure is too low, the reaction progresses slowly, and the particle size of the nanoparticles may increase due to the long-time reaction or the zirconium oxide may have a plurality of crystal systems. It is preferable to carry out under the above pressure, and it is more preferable to carry out at 0.2 MPaG or more. The temperature of the hydrothermal reaction is, for example, 150 to 250 ° C., and it may be maintained in the temperature range for, for example, about 2 to 24 hours.

When the zirconium oxide nanoparticles of the present invention are coated with the first carboxylic acid and an organic acid other than the first carboxylic acid, first, the zirconium oxide nanoparticles coated with the first carboxylic acid are firstly coated. It can be produced by preparing particles and then substituting the first carboxylic acid compound with the organic acid. Specifically, this substitution is performed by stirring a mixture (particularly a mixed solution) containing zirconium oxide nanoparticles coated with the first carboxylic acid and an organic acid. The mass ratio between the organic acid and the zirconium oxide nanoparticles coated with the first carboxylic acid is preferably 5/100 to 200/100.

Since the zirconium oxide nanoparticles of the present invention have good dispersibility in various media, they can be added to various solvents, monomers (monofunctional monomers and / or crosslinkable monomers), oligomers, polymers, etc., or combinations thereof. Is possible. The present invention also includes compositions containing zirconium oxide nanoparticles. The composition includes a dispersion containing zirconium oxide nanoparticles and a resin composition containing zirconium oxide nanoparticles.

Typical solvents include, for example, alcohols such as methanol, ethanol, n-propanol, isopropanol, and ethylene glycol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, and the like Esters such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; modified ethers such as propylene glycol monomethyl ether acetate (preferably ether-modified and / or ester-modified ethers, more preferably ether-modified and / or ester-modified) Alkylene glycols); benzene, toluene, xylene, ethylbenzene, trimethylbenzene, hexa , Cyclohexane, methylcyclohexane, ethylcyclohexane, mineral spirits; halogenated hydrocarbons such as dichloromethane and chloroform; amides such as dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone; water; minerals Examples thereof include oils such as oil, vegetable oil, wax oil, and silicone oil. One of these can be selected and used, or two or more can be selected and mixed for use. From the viewpoint of handleability, a solvent having a boiling point of 40 ° C. or more and 250 ° C. or less at normal pressure is suitable, and ketones, modified ethers and the like are suitable for resist applications described later.

The monofunctional monomer may be a compound having only one polymerizable carbon-carbon double bond, and is a (meth) acrylic acid ester; styrene, p-tert-butylstyrene, α-methylstyrene, m-methylstyrene. , Styrene monomers such as p-methylstyrene, p-chlorostyrene and p-chloromethylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid; hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate Examples include the body. Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). (Meth) acrylic acid alkyl esters such as acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate; (meth) acrylic such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate Acid cycloalkyl ester; Aralkyl (meth) acrylate such as benzyl (meth) acrylate; (Meth) acrylate ester having glycidyl group such as glycidyl (meth) acrylate, etc., but methyl (meth) acrylate is Preferred. These exemplified monofunctional monomers may be used alone, or two or more kinds may be appropriately mixed and used.

The crosslinkable monomer may be a compound containing a plurality of carbon-carbon double bonds copolymerizable with the carbon-carbon double bond of the monomer. Specific examples of the crosslinkable monomer include alkylene glycol poly (ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate) and the like. (Meth) acrylate; neopentyl glycol poly (meth) acrylate such as neopentyl glycol di (meth) acrylate and dineopentyl glycol di (meth) acrylate; trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) Trimethylolpropane poly (meth) acrylates such as acrylates; pentaerythritol tetra (meth) acrylates, dipentaerythritol hexa (meth) acrylates and other Polyfunctional (meth) acrylates such as taerythritol poly (meth) acrylate; polyfunctional styrene monomers such as divinylbenzene; polyfunctional allyl esters such as diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate System monomers and the like.

The composition containing the monomer corresponds to a curable composition. The curable composition constitutes a resin composition after curing, and such a curable composition is also included in the resin composition of the present invention. The composition of the present invention may be a resin composition containing the polymer (resin). In the case of constituting the resin composition of the present invention, the polymer used as the medium is, for example, polyamides such as 6-nylon, 66-nylon and 12-nylon; polyimides; polyurethanes; polyolefins such as polyethylene and polypropylene, PET Polyesters such as PBT, PBT, PEN; Polyvinyl chlorides; Polyvinylidene chlorides; Polyvinyl acetates; Polystyrenes; (Meth) acrylic resin-based polymers; ABS resins; Fluorine resins; Phenol / formalin resins, Cresol / formalin resins Phenolic resins such as: epoxy resins; amino resins such as urea resins, melamine resins, and guanamine resins. Moreover, soft resins and hard resins such as polyvinyl butyral resins, polyurethane resins, ethylene-vinyl acetate copolymer resins, and ethylene- (meth) acrylate copolymer resins are also included. Among the above, polyimides, polyurethanes, polyesters, (meth) acrylic resin polymers, phenol resins, amino resins, and epoxy resins are more preferable. These may be used alone or in combination of two or more.

The concentration of the zirconium oxide nanoparticles of the present invention in the composition can be appropriately set according to the use. However, when the composition is uncured or contains a polymer (resin), the composition is usually used. It is 90 mass% or less with respect to 100 mass% of all the components (the total of what is used among substitution covering type particle | grains, a solvent, a monomer, an oligomer, a polymer, and the polymer precursor mentioned later). If it exceeds 90% by mass, it may be difficult to uniformly disperse and the uncured composition may become cloudy. On the other hand, the lower limit is not particularly limited, but is, for example, 1% by mass or more in consideration of the solvent cost. More preferably, they are 5 mass% or more and 85 mass% or less, More preferably, they are 10 mass% or more and 80 mass% or less.

In addition, the resin composition of the present invention includes not only the composition of the polymer (polymer compound) and the zirconium oxide nanoparticles of the present invention, but also a monomer (polymer precursor) constituting the polymer, for example, Also included are compositions of a mixture of dicarboxylic acid and diamine, unsaturated carboxylic acid such as acrylic acid and methacrylic acid, its ester compound, and the like, and the zirconium oxide nanoparticles of the present invention. The resin composition of the present invention may be one containing both a polymer and a monomer, one containing a polymer and a solvent (coating material), or a molding resin used for a molding material such as an optical film. Also good.

Further, since the zirconium oxide nanoparticles of the present invention are remarkably excellent in dispersibility, the composition has good transparency even in a high concentration composition (dispersion). A composition in which zirconium oxide nanoparticles are dispersed at a high concentration is advantageous, for example, in improving the refractive index, and the refractive index can be adjusted according to various applications. When used as a high-concentration zirconium oxide nanoparticle composition, the amount of zirconium oxide nanoparticles in the composition is preferably 25% by mass or more, more preferably 30% by mass or more, and still more preferably Is 60% by mass or more. Although the upper limit is not particularly limited, the amount of zirconium oxide nanoparticles in the composition is preferably 90% by mass or less.

The resin composition of the present invention (including the cured curable composition) may contain zirconium oxide nanoparticles and other additive components of the resin. Examples of the additive component include a curing agent, a curing accelerator, a colorant, a release agent, a reactive diluent, a plasticizer, a stabilizer, a flame retardant aid, and a crosslinking agent. The nanoparticles of the present invention can be colored by containing an appropriate transition metal, and the color can be changed by changing the type and amount of the transition metal according to the application.

The shape of the resin composition of the present invention (including the cured curable composition) is not particularly limited, and may be a molding material such as a plate, a sheet, a film, or a fiber.

Since the zirconium oxide nanoparticles of the present invention are coated with the specific first carboxylic acid, they have good dispersibility in an organic medium, and are obtained by firing a composition containing the zirconium oxide nanoparticles of the present invention. The ceramic material obtained has good ceramic properties such as translucency, toughness, and strength, and the present invention relates to the zirconium oxide nanoparticles of the present invention (zirconium oxide nanoparticles coated with the first carboxylic acid and containing the metal element M). Also included are ceramic materials obtained from (particles). Moreover, since the zirconium oxide nanoparticle of this invention contains at least 1 sort (s) of Y, Al, La, Ce, and In in a preferable aspect, it has a stable crystal structure. That is, when the zirconium oxide nanoparticles of the present invention in such a preferred embodiment are fired, changes in the crystal structure can be suppressed, and cracking and strength reduction due to the change in the crystal structure can be suppressed.

The ceramic material obtained from the zirconium oxide nanoparticles of the present invention (specifically, the ceramic material obtained by firing) can be obtained by firing the zirconium oxide nanoparticles of the present invention alone. Further, the zirconium oxide nanoparticles of the present invention can be obtained by firing a composition containing additives such as alumina, spinel, YAG, mullite, and an aluminum borate compound. Furthermore, the composition which consists of a zirconium oxide nanoparticle of this invention and a binder can also be obtained by baking. The firing temperature at this time may be about 500 to 1600 ° C. Firing can be performed by a known method. Pressure may be applied to promote sintering during firing. Further, it may be fired in air, an oxygen atmosphere, a mixed atmosphere of oxygen and air, or may be fired in an inert atmosphere such as nitrogen or argon. Each can be appropriately selected according to the use after firing.

The ceramic material obtained from the zirconium oxide nanoparticles of the present invention contains a complex oxide of usually added metal and zirconium, a mixture of each single oxide, or both.

The present application is Japanese Patent Application No. 2015-194172 filed on September 30, 2015, Japanese Patent Application No. 2016-039322 filed on March 1, 2016, March 1, 2016 It claims the benefit of priority based on the Japanese Patent Application No. 2016-039323 filed and the Japanese Patent Application No. 2016-108539 filed on May 31, 2016. Japanese Patent Application No. 2015-194172 filed on September 30, 2015, Japanese Patent Application No. 2016-039322 filed on March 1, 2016, filed on March 1, 2016 The entire contents of Japanese Patent Application No. 2016-039323 and Japanese Patent Application No. 2016-108539 filed on May 31, 2016 are incorporated herein by reference.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and can of course be implemented with appropriate modifications within a range that can be adapted to the above-described gist. Included in the range.

The physical properties and characteristics disclosed in the examples were measured by the following methods.

(1) Analysis of crystal structure The crystal structure of zirconium oxide particles was analyzed using an X-ray diffractometer (RINT-TTRIII, manufactured by Rigaku Corporation). The measurement conditions are as follows.
X-ray source: CuKα (0.154 nm)
X-ray output setting: 50 kV, 300 mA
Sampling width: 0.0200 °
Scan speed: 10.0000 ° / min
Measurement range: 5 to 90 °
Measurement temperature: 25 ° C

(2) Determination of the ratio of tetragonal and / or cubic and monoclinic crystals Based on values calculated using an X-ray diffractometer (Rigaku Corporation, RINT-TTRIII), calculation software (Rigaku Corporation, PDXL) ) By the reference intensity ratio method (RIP method) (peak assignment was also in accordance with the specification of the calculation software). Note that it is difficult to distinguish between cubic crystals and tetragonal crystals by X-ray diffraction measurement of the pre-fired coated zirconia nanoparticles, and even when cubic crystals are present, the ratio is counted as the ratio of tetragonal crystals.

(3) Calculation of crystallite size by X-ray diffraction analysis The crystallite size of zirconium oxide particles is based on the half-width of the 30 ° peak analyzed and calculated by an X-ray diffractometer (RINT-TTRIII, manufactured by Rigaku Corporation). The calculation software (Rigaku Corporation, PDXL) was used for calculation.

(4) Measurement of weight (mass) reduction rate Using a TG-DTA (thermogravimetric-suggested thermal analysis) device, the temperature of zirconium oxide particles coated at 10 ° C./min from room temperature to 800 ° C. was increased in an air atmosphere. The weight (mass) reduction rate of the particles was measured. From this weight (mass) reduction rate, the ratio of the first carboxylic acid covering the zirconium oxide particles and the ratio of zirconium oxide can be known.

(5) Measurement of ¹ H-NMR The coated zirconium oxide particles were dispersed in deuterated chloroform to obtain a measurement sample, and measurement was performed using “Unity Plus” (resonance frequency: 400 MHz, integration number: 16 times) manufactured by Varian. . Based on the integration ratio of the following chemical shift (tetramethylsilane standard) peak, the molar ratio of each compound was determined.
i) 2-ethylhexanoic acid (1.0-0.5 ppm: 6H)
ii) 2-ethylhexanoic acid-derived carboxylate (1.0-0.5 ppm: 6H)
iii) 2-acryloyloxyethyl succinic acid (6.7-5.7 ppm: 3H, 4.5-4.0 ppm: 4H)
iv) 3-Methacryloxypropyltrimethoxysilane (6.5-5.5 ppm: 2H, 4.5-4.0 ppm: 2H, 4.0-3.5 ppm: 9H, 1.0-0.5 ppm: 2H) )

(6) X-ray fluorescence analysis Using a fluorescent X-ray analyzer (manufactured by ZSX Primus II Rigaku Corporation), the zirconium content in the coated zirconium oxide particles and the content of the metal element M were measured.

(7) Absorbance measurement Absorbance measurement was performed by measuring diffuse reflection with an integrating sphere using barium sulfate using UV-3100 manufactured by Shimadzu Corporation. The measurement wavelength was 200 to 800 nm in increments of 0.2 nm.

Example 1-1
Production of Coated Yttria Stabilized Zirconium Oxide Nanoparticles 1 (Coated YSZ Particles 1) Coated with 2-Ethylhexanoic Acid and / or 2-ethylhexanoic Acid-Derived Carboxylate 2-Ethylhexanoate Zirconium Mineral Spirit Solution ( 91.6 g, zirconium 2-ethylhexanoate content 44% by mass, manufactured by Daiichi Rare Element Chemical Co., Ltd.) yttrium 2-ethylhexanoate (III) (1.3 g, yttrium content 7.9% by mass, Mitsuru Wako Chemical Co., Ltd.) and pure water (15.7 g) were mixed and charged into a 200 mL hydrothermal synthesis vessel. The vessel was heated to 190 ° C. and kept at that temperature for 16 hours for reaction. The pressure during hydrothermal synthesis was 1.3 MPaG (gauge pressure). The mixed solution after the reaction was taken out, and the precipitate accumulated at the bottom was separated by filtration to recover 15 g of a viscous solid. This viscous solid was taken in a beaker, washed with 75 g of methanol, and then filtered through a Kiriyama funnel. The obtained solid was dried under reduced pressure at room temperature, and methanol was removed to recover 11 g of white yttria-stabilized zirconium oxide nanoparticles 1 (coated YSZ particles 1).

When the crystal structure of the obtained coated YSZ particle 1 was confirmed, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected. From the intensity of the diffraction lines, the ratio of tetragonal crystals to monoclinic crystals was 91/9. The particle diameter (crystallite diameter) was 5 nm. In X-ray diffraction measurement, it is difficult to distinguish between cubic crystals and tetragonal crystals, and even when cubic crystals are present, the ratio is counted as the ratio of tetragonal crystals.

Furthermore, the mass reduction rate of the coated YSZ particles 1 measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 14% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid covering the coated YSZ particle 1 was 14% by mass of the entire coated YSZ particle 1.

Furthermore, the weight abundance ratio of zirconium and yttrium in the coated YSZ particles 1 measured according to “(6) X-ray fluorescence analysis” described above was 99/1.

Example 1-2
Production of Coated Yttria Stabilized Zirconium Oxide Nanoparticles 2 (Coated YSZ Particles 2) Coated with 2-Ethylhexanoic Acid and / or 2-ethylhexanoic Acid-Derived Carboxylate 2-Ethylhexanoate Zirconium Mineral Spirit Solution ( 86.7 g, zirconium 2-ethylhexanoate content 44% by mass, manufactured by Daiichi Rare Element Chemical Co., Ltd.) and 2-ethylhexanoate yttrium (III) (4.8 g, yttrium content 7.9% by mass, Mitsuru Wako Chemical Co., Ltd.) and pure water (15.0 g) were mixed and charged into a 200 mL hydrothermal synthesis vessel. The vessel was heated to 190 ° C. and kept at that temperature for 16 hours for reaction. The pressure during hydrothermal synthesis was 1.3 MPaG (gauge pressure). The mixed solution after the reaction was taken out, and the precipitate accumulated at the bottom was separated by filtration to recover 15 g of a viscous solid. This viscous solid was taken in a beaker, washed with 75 g of methanol, and then filtered through a Kiriyama funnel. The obtained solid was dried under reduced pressure at room temperature, and methanol was removed to recover 11 g of white yttria-stabilized zirconium oxide nanoparticles 2 (coated YSZ particles 2).

When the crystal structure of the obtained coated YSZ particles 2 was confirmed, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected. From the intensity of the diffraction lines, the ratio of tetragonal crystals to monoclinic crystals was 94/6. The particle diameter (crystallite diameter) was 4 nm.

Furthermore, the mass reduction rate of the coated YSZ particles 2 measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 14% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid covering the coated YSZ particle 2 was 14% by mass of the entire coated YSZ particle 2.

Furthermore, the weight abundance ratio of zirconium and yttrium in the coated YSZ particles 2 measured according to “(6) X-ray fluorescence analysis” described above was 95/4.

Example 1-3
Production of Coated Yttria Stabilized Zirconium Oxide Nanoparticles 3 (Coated YSZ Particles 3) Coated with 2-Ethylhexanoic Acid and / or 2-ethylhexanoic Acid-Derived Carboxylate 2-Ethylhexanoate Zirconium Mineral Spirit Solution ( 80.4 g, zirconium 2-ethylhexanoate content 44% by mass, manufactured by Daiichi Rare Element Chemical Co., Ltd.) and 2-ethylhexanoate yttrium (III) (11.7 g, yttrium content 7.9% by mass, Mitsuru Wako Chemical Co., Ltd.) and pure water (13.8 g) were mixed and charged into a 200 mL hydrothermal synthesis vessel. The vessel was heated to 190 ° C. and kept at that temperature for 16 hours for reaction. The pressure during hydrothermal synthesis was 1.3 MPaG (gauge pressure). The mixed solution after the reaction was taken out, and the precipitate accumulated at the bottom was separated by filtration to recover 13 g of a viscous solid. This viscous solid was taken in a beaker, washed with 65 g of methanol, and then filtered through a Kiriyama funnel. The obtained solid was dried under reduced pressure at room temperature, and methanol was removed to recover 10 g of white yttria-stabilized zirconium oxide nanoparticles 3 (coated YSZ particles 3).

When the crystal structure of the obtained coated YSZ particles 3 was confirmed, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected, and the ratio of tetragonal crystals to monoclinic crystals was 100/0 from the intensity of the diffraction lines. The particle diameter (crystallite diameter) was 4 nm.

Furthermore, the mass reduction rate of the coated YSZ particles 3 measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 15% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid covering the coated YSZ particles was 15% by mass of the entire coated YSZ particles 3.

Furthermore, the weight abundance ratio of zirconium and yttrium in the coated YSZ particles 3 measured according to “(6) X-ray fluorescence analysis” described above was 91/9.

Example 1-4
Preparation of Coated Yttria Stabilized Zirconium Oxide Nanoparticles 4 (Coated YSZ Particles 4) Coated with 2-Ethylhexanoic Acid and / or 2-Ethylhexanoic Acid-Derived Carboxylate 2-Ethylhexanoate Zirconium Mineral Spirit Solution ( 83.0 g, zirconium 2-ethylhexanoate content 44% by mass, manufactured by Daiichi Rare Element Chemical Co., Ltd.) yttrium 2-ethylhexanoate (III) (6.3 g, yttrium content 7.9% by mass, Mitsuru Wako Chemical Co., Ltd.) and pure water (15.8 g) were mixed and charged into a 200 mL hydrothermal synthesis vessel. The vessel was heated to 190 ° C. and kept at that temperature for 8 hours to be reacted. The pressure during hydrothermal synthesis was 1.4 MPaG (gauge pressure). The mixed solution after the reaction was taken out, and the precipitate accumulated at the bottom was separated by filtration to recover 13 g of a viscous solid. This viscous solid was taken in a beaker, washed with 70 g of methanol, and then filtered through a Kiriyama funnel. The obtained solid was dried under reduced pressure at room temperature, and methanol was removed to recover 10 g of white yttria-stabilized zirconium oxide nanoparticles 4 (coated YSZ particles 4).

When the crystal structure of the obtained coated YSZ particles 4 was confirmed, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected. From the intensity of the diffraction lines, the ratio of tetragonal crystals to monoclinic crystals was 97/3. The particle diameter (crystallite diameter) was 5 nm.

Furthermore, the mass reduction rate of the coated YSZ particles 4 measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 17% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid covering the coated YSZ particles 4 was 17% by mass of the entire coated YSZ particles 4.

Furthermore, the weight abundance ratio of zirconium and yttrium in the coated YSZ particles 4 measured according to “(6) X-ray fluorescence analysis” described above was 95/5.

Comparative Example 1-1
Preparation of coated zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate (coated ZrO ₂ particles) Zirconium 2-ethylhexanoate mineral spirit solution (90.4 g, Pure water (15.5 g) was mixed with a zirconium 2-ethylhexanoate content of 44% by mass, manufactured by Daiichi Rare Element Chemical Co., Ltd., and charged into a 200 mL hydrothermal synthesis vessel. The vessel was heated to 190 ° C. and kept at that temperature for 16 hours for reaction. The pressure during hydrothermal synthesis was 1.3 MPaG (gauge pressure). The mixed solution after the reaction was taken out, and the precipitate accumulated at the bottom was separated by filtration to collect 15 g of a wet cake. This viscous solid was taken in a beaker, washed with 75 g of methanol, and then filtered through a Kiriyama funnel. The obtained solid was dried under reduced pressure at room temperature, and methanol was removed to recover 11 g of white zirconium oxide nanoparticles (coated ZrO ₂ particles).

When the crystal structure of the obtained coated ZrO ₂ particles was confirmed, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected. From the intensity of the diffraction lines, the ratio of tetragonal crystals to monoclinic crystals was 74/26. The particle diameter (crystallite diameter) was 5 nm.

Furthermore, the mass reduction rate of the coated ZrO ₂ particles measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 14% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the coated zirconium oxide particles accounted for 14% by mass of the entire coated zirconium oxide particles.

Example 1-5
Production of yttria-stabilized zirconium oxide nanoparticles 5 (coated YSZ particles 5) coated with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate and 2-acryloyloxyethyl succinic acid Example 1 -2 The coated YSZ particles 2 (10 g) and 2-acryloyloxyethyl succinic acid (1.5 g) obtained in -2 are uniformly dispersed in propylene glycol monomethyl ether acetate (12 g, hereinafter referred to as “PGMEA”). Until mixed. Subsequently, n-hexane (36 g) was added to agglomerate the dispersed particles to make the solution cloudy, and the aggregated particles were separated from the cloudy liquid by filtration. Thereafter, the separated aggregated particles are added into n-hexane (36 g), and after stirring for 10 minutes, the aggregated particles are separated by filtration, and the obtained particles are vacuum-dried at room temperature, whereby 2-ethylhexanoic acid and Yttria-stabilized zirconium oxide nanoparticles 5 (coated YSZ particles 5) surface-treated with carboxylate derived from 2-ethylhexanoic acid and 2-acryloyloxyethyl succinic acid were obtained.
The obtained coated YSZ particles 5 were dispersed in deuterated chloroform, used as measurement data, and analyzed by ¹ H-NMR. As a result, it was found that the molar ratio of 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate to 2-acryloyloxyethylsuccinic acid was 29:71.

Furthermore, the mass reduction rate of the coated YSZ particles 5 measured according to the above-mentioned “(4) Measurement of weight (mass) reduction rate” was 18% by mass. Therefore, 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate and 2-acryloyloxyethyl succinic acid covering the coated zirconium oxide particles are 18% by mass of the entire coated zirconium oxide particles. I found out.

Example 1-6
Production of inorganic oxide fine particle-containing solution 1 By mixing the coated YSZ particles 5 (7 g) obtained in Example 1-5 and methyl ethyl ketone (3 g) and stirring until uniform, the inorganic oxide fine particle-containing solution 1 was obtained.

Example 1-7
Production of inorganic oxide fine particle-containing solution 2 Coated YSZ particles 5 (7 g) obtained in Example 1-5, methyl ethyl ketone (3 g) and phosphate ester KAYAMERPM-21 (manufactured by Nippon Kayaku Co., Ltd., 0.1 g) The inorganic oxide fine particle containing solution 2 was obtained by mix | blending and stirring until it became uniform.

Example 1-8
Production of Yttria Stabilized Zirconium Oxide Nanoparticles 6 (Coated YSZ Particles 6) Coated with 2-Ethylhexanoic Acid and / or 2-Ethylhexanoic Acid-Derived Carboxylate and 3-Methacryloxypropyltrimethoxysilane Example 1 The coated yttria-stabilized zirconium oxide nanoparticles 2 (10 g) obtained in -2 were dispersed in methyl isobutyl ketone (40 g) to prepare a cloudy slurry. To the solution, 3-methacryloxypropyltrimethoxysilane (1.0 g, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503) and water (0.9 g) are added as a surface treatment agent, and the mixture is heated to reflux at 80 ° C. for 1 hour. A transparent dispersion solution was obtained. Subsequently, n-hexane was added to agglomerate the dispersed particles to make the solution cloudy. Aggregated particles are separated from the white turbid solution by filtration, dried by heating at room temperature, and yttria stabilized with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate and 3-methacryloxypropyltrimethoxysilane. Zirconium oxide nanoparticles 6 (coated YSZ particles 6) were prepared.

The mass reduction rate of the coated YSZ particles 5 when the temperature was raised to 800 ° C. at a rate of 10 ° C./min in an air atmosphere by TG-DTA (thermogravimetric-suggested thermal analysis) of the obtained coated YSZ particles 5 When measured, the reduction rate was 15% by mass. This confirmed that the organic content of the coated YSZ particles 6 was 15% by mass.

The obtained coated YSZ particles 6 were dispersed in deuterated chloroform and used as measurement data, and analyzed by ¹ H-NMR. As a result, it was found that the molar ratio of 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate to 3-methacryloxypropyltrimethoxysilane was 59:41.

Example 1-9
Production of inorganic oxide fine particle-containing solution 3 By mixing the coated YSZ particles 6 (7 g) obtained in Example 1-8 and methyl ethyl ketone (3 g) and stirring until uniform, the inorganic oxide fine particle-containing solution 3 was obtained.

Example 1-10
Production of inorganic oxide fine particle-containing solution 4 The coated YSZ particles 6 (7 g) obtained in Example 1-8, methyl ethyl ketone (3 g), and phosphoric ester Phoslex A-208 (1 g, manufactured by SC Organic Chemical Co., Ltd.) were blended. By stirring until uniform, an inorganic oxide fine particle-containing solution 4 was obtained.

Example 1-11
Preparation of benzyl acrylate dispersion of coated YSZ particles 6 Benzyl acrylate (7 g, manufactured by Hitachi Chemical Co., Ltd.) was added to the inorganic oxide particle-containing solution 4 (10 g) obtained in Example 1-10 and stirred until uniform. 14 g of benzyl acrylate dispersion of coated YSZ particles 6 was obtained by removing methyl ethyl ketone at 50 ° C./depressurized condition while stirring was continued.

Example 1-12
Production of Inorganic Oxide Fine Particle-Containing Composition 0.02 g of Irgacure 184 was added to 1 g of the benzyl acrylate dispersion of the coated YSZ particles 6 and stirred until uniform to obtain an inorganic oxide fine particle-containing composition.

Example 1-13
Production of Transparent Cured Film Containing Inorganic Oxide Fine Particles The inorganic oxide-containing composition obtained in Example 1-12 is placed on a glass substrate, a 100 μm film is applied with an applicator, and UV-cured to perform inorganic oxidation. A transparent cured film containing product fine particles was obtained.

Example 1-14
Change in crystal system before and after calcination of coated YSZ particles 1 The coated YSZ particles 1 (1 g, tetragonal / monoclinic = 91/9) obtained in Example 1-1 were weighed in a combustion boat, and 1000 Firing was carried out at 3 ° C. for 3 hours. When the crystal structure of the ash content of the recovered coated YSZ particles 1 was confirmed, it was tetragonal / monoclinic = 28/72.

Example 1-15
Crystalline system change before and after calcination of coated YSZ particles 2 The coated YSZ particles 2 (1 g, tetragonal / monoclinic crystal = 94/6) obtained in Example 1-2 were weighed into a combustion boat, and 1000 Firing was carried out at 3 ° C. for 3 hours. When the crystal structure of the ash content of the recovered coated YSZ particles 2 was confirmed, it was tetragonal / monoclinic crystal = 98/2, and it was confirmed that the crystal system was hardly changed.

Example 1-16
Change in crystal system before and after firing of coated YSZ particles 3 The coated YSZ particles 3 (1 g, tetragonal / monoclinic crystal = 100/0) obtained in Example 1-3 were weighed into a combustion boat, and 1000 Firing was carried out at 3 ° C. for 3 hours. When the crystal structure of the ash content of the recovered coated YSZ particles 3 was confirmed, it was tetragonal / monoclinic crystal = 100/0, and it was confirmed that the crystal system was not changed at all.

Comparative Example 1-2
Coating type ZrO ₂ grains the crystal system changes Comparative Example 1-1 obtained in coated form ZrO ₂ particles fired before and after (1 g, tetragonal / monoclinic = 74/26) was weighed into combustion boats, 1000 Firing was carried out at 3 ° C. for 3 hours. When the crystal structure of the ash content of the recovered coated ZrO ₂ particles was confirmed, it was tetragonal / monoclinic crystal = 12/88, and it was confirmed that the crystal system was greatly changed.

Example 2-1
Preparation of lanthanum-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Zirconium 2-ethylhexanoate mineral spirit solution (83 g, zirconium content 12 mass%, first rare Elemental Chemical Industry Co., Ltd.) was mixed with 2-ethylhexanoic acid lanthanum (III) (19 g, lanthanum content 7 mass%, Wako Pure Chemical Industries, Ltd.) and pure water (16 g), and a 200 mL hydrothermal synthesis vessel Was charged. The vessel was heated to 190 ° C. and kept at that temperature for 8 hours to be reacted. The pressure during hydrothermal synthesis was 1.4 MPaG (gauge pressure). 14 g of white lanthanum-containing zirconium oxide nanoparticles were recovered by taking out the mixed solution after the reaction and removing the solvent.

When the crystal structure of the lanthanum-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals or cubic crystals were detected, and the above “(3) X-ray diffraction analysis” The crystallite diameter measured according to “Calculation of crystallite diameter by” was 3 nm.

The mass reduction rate of the coated lanthanum-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 24% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the lanthanum-containing zirconium oxide nanoparticles was 24% by mass of the total coated lanthanum-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium to lanthanum in the lanthanum-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 89:10.

Example 2-2
Preparation of tin-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that tin (II) hexanoate (4.9 g, tin content 29 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of white tin-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the tin-containing zirconia nanoparticles was measured according to “(1) Analysis of crystal structure” described above, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and the above “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 3 nm.

The mass reduction rate of the coated tin-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the tin-containing zirconium oxide nanoparticles was 25% by mass of the total coated tin-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium and tin in the tin-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 87:13.

Example 2-3-1
Preparation of zinc-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that zinc hexanoate (II) (6.6 g, zinc content 15% by mass, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of white zinc-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the zinc-containing zirconia nanoparticles was measured according to “(1) Analysis of crystal structure” described above, diffraction lines belonging to tetragonal and monoclinic crystals were detected, and the above “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

The mass reduction rate of the coated zinc-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 26% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the zinc-containing zirconium oxide nanoparticles was 26% by mass of the total coated zinc-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium and zinc in the zinc-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 90: 9.

Example 2-3-2
The synthesis was performed in the same manner as in Example 2-3-1, except that 0.66 g of zinc 2-ethylhexanoate (II) in Example 2-3-1 was used. After the reaction, 13 g of white zinc-containing zirconium oxide nanoparticles were recovered.

Furthermore, the weight ratio of zirconium to zinc in the zinc-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 98: 1.

Example 2-3-3
The synthesis was performed in the same manner as in Example 2-3-1, except that 1.3 g of zinc 2-ethylhexanoate (II) in Example 2-3-1 was used. After the reaction, 14 g of white zinc-containing zirconium oxide nanoparticles were recovered.

Furthermore, the weight ratio of zirconium to zinc in the zinc-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 97: 2.

Example 2-3-4
The synthesis was performed in the same manner as in Example 2-3-1, except that 2.6 g of zinc 2-ethylhexanoate (II) in Example 2-3-1 was used. After the reaction, 14 g of white zinc-containing zirconium oxide nanoparticles were recovered.

Furthermore, the weight ratio of zirconium and zinc in the zinc-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 95: 4.

Example 2-4
Preparation of cerium-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, The compound was synthesized in the same manner as in Example 2-1, except that cerium (III) hexanoate ALFA AESAR (14 g, cerium content 12 mass%, registered trademark, manufactured by Johnson Matthey) was used. After the reaction, 15 g of yellow-brown cerium-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the cerium-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

The mass reduction rate of the coated cerium-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 26% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the cerium-containing zirconium oxide nanoparticles was 26% by mass of the total coated cerium-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium to cerium in the cerium-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 88:12.

Example 2-5
Preparation of indium-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that indium (III) hexanoate (28 g, indium content: 5 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of white indium-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the indium-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystal and monoclinic crystal were detected, and the above “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 5 nm.

The mass reduction rate of the coated indium-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 27% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the indium-containing zirconium oxide nanoparticles was 27% by mass of the total coated indium-containing zirconium oxide nanoparticles. .

Furthermore, the weight abundance ratio of zirconium and indium in the indium-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 86:14.

Example 2-6
Preparation of bismuth-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that bismuth (III) hexanoate (10 g, bismuth content 25% by mass, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of white bismuth-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the bismuth-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 5 nm.

Further, the mass reduction rate of the coated bismuth-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the bismuth-containing zirconium oxide nanoparticles was 25% by mass of the total coated bismuth-containing zirconium oxide nanoparticles. .

Furthermore, the weight abundance ratio of zirconium and bismuth in the bismuth-containing zirconium oxide particles measured according to “(6) X-ray fluorescence analysis” was 80:20.

Example 2-7
Preparation of iron-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that iron (III) hexanoate (3.0 g, iron content 6 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of reddish brown iron-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the iron-containing zirconia nanoparticles was measured according to “(1) Analysis of crystal structure” described above, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 5 nm.

Further, the mass reduction rate of the coated iron-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 23% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the iron-containing zirconium oxide nanoparticles was 23% by mass of the total coated iron-containing zirconium oxide nanoparticles. .

Furthermore, the weight abundance ratio of zirconium and iron in the iron-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 96: 3.

Example 2-8-1
Preparation of cobalt-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that cobalt (II) hexanoate (1.8 g, cobalt content 11 mass%, manufactured by Sigma-Aldrich) was used. After the reaction, 14 g of purple cobalt-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the cobalt-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated cobalt-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the cobalt-containing zirconium oxide nanoparticles was 25% by mass of the total coated cobalt-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium to cobalt in the cobalt-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 96: 3.

Example 2-8-2
Preparation of cobalt-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that cobalt (II) hexanoate (6.4 g, cobalt content 11 mass%, manufactured by Sigma-Aldrich) was used. After the reaction, 15 g of purple cobalt-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the cobalt-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated cobalt-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the cobalt-containing zirconium oxide nanoparticles was 25% by mass of the total coated cobalt-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium to cobalt in the cobalt-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 89:10.

Example 2-9
Preparation of manganese-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, Synthesis was performed in the same manner as in Example 2-1, except that manganese (II) hexanoate (2.4 g, manganese content 8 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) was used. After the reaction, 14 g of purple manganese-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the manganese-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated manganese-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Accordingly, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the manganese-containing zirconium oxide nanoparticles was 25% by mass of the total coated manganese-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium and manganese in the manganese-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 96: 3.

Example 2-10
Preparation of nickel-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid Instead of lanthanum (III) 2-ethylhexanoate in Example 2-1, The synthesis was performed in the same manner as in Example 2-1, except that nickel (II) hexanoate (2.0 g, nickel content 10% by mass, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used. After the reaction, 14 g of light red nickel-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the nickel-containing zirconia nanoparticles was measured according to the above-mentioned “(1) Analysis of crystal structure”, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated nickel-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the nickel-containing zirconium oxide nanoparticles was 25% by mass of the total coated nickel-containing zirconium oxide nanoparticles. .

Furthermore, the weight ratio of zirconium to nickel in the nickel-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 96: 3.

Example 2-11-1
Preparation of copper-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid and neodecanoic acid and / or carboxylate derived from neodecanoic acid 2-ethyl of Example 2-1 Synthesis was performed in the same manner as in Example 2-1, except that copper (II) neodecanoate (4.5 g, copper content 5 mass%, manufactured by Nippon Chemical Industry Co., Ltd.) was used instead of lanthanum hexanoate (III). . After the reaction, 14 g of dark green copper-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the copper-containing zirconia nanoparticles was measured according to “(1) Analysis of crystal structure” described above, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated copper-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 27% by mass. Therefore, 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate coating copper-containing zirconium oxide nanoparticles and neodecanoic acid and / or neodecanoic acid-derived carboxylate are coated with copper-containing zirconium oxide. It was found to be 27% by mass of the total nanoparticles.

Furthermore, the weight ratio of zirconium and copper in the copper-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 96: 3.

Example 2-11-2
Preparation of copper-containing zirconia nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid and neodecanoic acid and / or carboxylate derived from neodecanoic acid 2-ethyl of Example 2-1 The synthesis was performed in the same manner as in Example 2-1, except that copper (II) neodecanoate (15 g, copper content 5 mass%, manufactured by Nippon Chemical Industry Co., Ltd.) was used instead of lanthanum hexanoate (III). After the reaction, 16 g of dark green copper-containing zirconium oxide nanoparticles were recovered.

When the crystal structure of the copper-containing zirconia nanoparticles was measured according to “(1) Analysis of crystal structure” described above, diffraction lines attributed to tetragonal crystals and monoclinic crystals were detected, and “(3) X-ray diffraction” was detected. The crystallite diameter measured according to “Calculation of crystallite diameter by analysis” was 4 nm.

Further, the mass reduction rate of the coated copper-containing zirconium oxide nanoparticles measured according to the above “(4) Measurement of weight (mass) reduction rate” was 28% by mass. Therefore, 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate coating copper-containing zirconium oxide nanoparticles and neodecanoic acid and / or neodecanoic acid-derived carboxylate are coated with copper-containing zirconium oxide. It was found to be 28% by mass of the total nanoparticles.

Furthermore, the weight ratio of zirconium and copper in the copper-containing zirconium oxide particles measured according to the above “(6) X-ray fluorescence analysis” was 90: 9.

1 to 7 show X-ray diffraction charts obtained by analyzing the zirconia nanoparticles containing each metal element M in accordance with the above “(1) Analysis of crystal structure”. For the lanthanum-containing zirconia nanoparticles of Example 2-1, the cerium-containing zirconia nanoparticles of Example 2-4, and the indium-containing zirconia nanoparticles of Example 2-5, these particles were calcined at 1000 ° C. for 2 hours. The crystal structure of the ceramic material obtained in this way was also analyzed.

Any metal element M was found to exist as a complex oxide of zirconium and metal element M in the state of nanoparticles. Further, it was found that lanthanum, cerium and indium exist as complex oxides of these elements and zirconium even after firing, and have the effect of stabilizing tetragonal zirconium oxide even after firing.

Example 3-1
Preparation of iron-containing yttria-stabilized zirconia particles coated with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate Zirconium 2-ethylhexanoate mineral spirit solution (83.0 g, zirconium content 12 mass% 1st Rare Element Chemical Industry Co., Ltd.), 2-ethylhexanoate yttrium (III) (3.66 g, yttrium content 17% by mass, manufactured by Nippon Chemical Industry Co., Ltd.) and iron 2-ethylhexanoate (II) ( 0.35 g, iron content 6 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) and pure water (15.8 g) were mixed and charged into a 200 mL hydrothermal synthesis container. The vessel was heated to 190 ° C. and kept at that temperature for 8 hours to be reacted. The pressure during hydrothermal synthesis was 1.4 MPaG (gauge pressure). When the mixed solution after the reaction was taken out and separated to remove the aqueous phase, a nanoparticle dispersion was obtained. The solution was decompressed to remove the organic solvent and dried at 180 ° C. to recover 18 g of light yellow coated iron-containing yttria-stabilized zirconia nanoparticles. Yttria-stabilized zirconia means zirconia whose crystal structure is stabilized by yttria, and is hereinafter referred to as YSZ.

When the crystal structure of the coated iron-containing YSZ nanoparticles was measured according to “(1) Analysis of crystal structure” described above, the ratio of tetragonal / monoclinic crystal was 97/3. In X-ray diffraction measurement, it is difficult to distinguish between cubic crystals and tetragonal crystals, and even when cubic crystals are present, the ratio is counted as the ratio of tetragonal crystals.

The crystallite diameter of the coated iron-containing YSZ particles measured according to the above-mentioned “(3) Calculation of crystallite diameter by X-ray diffraction analysis” was 5 nm.

The mass reduction rate of the coated iron-containing YSZ nanoparticles measured according to “(4) Measurement of weight (mass) reduction rate” described above was 25% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the coated iron-containing YSZ nanoparticles was 25% by mass of the entire coated iron-containing YSZ nanoparticles.

Further, the weight ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to the above “(6) X-ray fluorescence analysis” was 94: 5.7: 0.2.

Furthermore, the sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles for 3 hours at 1000 ° C. had a yellow color and was uniformly colored as apparent from the results of the absorbance measurement shown in FIG. Further, when the crystal structure was measured according to the above “(1) Analysis of crystal structure”, the pattern shown in FIG. A pattern was obtained and the tetragonal proportion was 100%. FIG. 9C shows an X-ray diffraction pattern of tetragonal zirconium oxide.

Example 3-2
18 g of light yellow coated iron-containing YSZ nanoparticles were recovered in the same manner as in Example 3-1, except that 0.18 g of iron (II) 2-ethylhexanoate of Example 3-1 was used.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.8: 0.1. A sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles for 3 hours at 1000 ° C. was lighter yellow than the above Example 3-1, and was uniformly colored. The crystal structure was 100% tetragonal.

Example 3-3
18 g of light yellow coated iron-containing YSZ nanoparticles were recovered in the same manner as in Example 3-1, except that 0.7 g of iron (II) 2-ethylhexanoate of Example 3-1 was used.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.7: 0.4. The sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles at 1000 ° C. for 3 hours was darker yellow than Example 3-1 and colored uniformly. The crystal structure was 100% tetragonal.

Example 3-4
19 g of yellow coated iron-containing YSZ nanoparticles were recovered in the same manner as in Example 3-1, except that 1.4 g of iron (II) 2-ethylhexanoate of Example 3-1 was used.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.7: 0.8. The sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles for 3 hours at 1000 ° C. was brown and uniformly colored.

Example 3-5
19 g of brown coated iron-containing YSZ nanoparticles were recovered in the same manner as in Example 3-1, except that 2.8 g of iron (II) 2-ethylhexanoate of Example 3-1 was used.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.6: 1.5. The sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles for 3 hours at 1000 ° C. was brown and uniformly colored.

Example 3-6
Example 2 was used except that 0.2 g of cobalt (II) 2-ethylhexanoate (Aldrich, 65% mineral spirit solution) was used instead of iron (II) 2-ethylhexanoate of Example 3-1. In the same manner as in 3-1, 18 g of brown coated cobalt-containing YSZ nanoparticles were recovered.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and cobalt in the coated cobalt-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.7: 0.2. The absorbance measurement results of the sample obtained by calcining the obtained coated cobalt-containing YSZ nanoparticles for 3 hours at 1000 ° C. are as shown in FIG. 8, and the color of the sample was gray and uniformly colored. The crystal structure was 100% tetragonal.

Example 3-7
Aside from using 0.3 g of manganese 2-ethylhexanoate (manufactured by Nippon Chemical Industry Co., Ltd., trade name Nikka Octix Manganese 8%) instead of iron (II) 2-ethylhexanoate of Example 3-1, In the same manner as in Example 3-1, 18 g of purple coated manganese-containing YSZ nanoparticles were recovered.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and manganese in the coated manganese-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.7: 0.2. The absorbance measurement result of the sample obtained by calcining the obtained coated manganese-containing YSZ nanoparticles for 3 hours at 1000 ° C. is as shown in FIG. 8, and the color of the sample was gray and uniformly colored. The crystal structure was 100% tetragonal.

Example 3-8
Aside from using 0.2 g of nickel 2-ethylhexanoate (manufactured by Nippon Chemical Industry Co., Ltd., trade name Nikka Octix Nickel 10%) instead of iron (II) 2-ethylhexanoate of Example 3-1, In the same manner as in Example 3-1, 18 g of pale yellow coated nickel-containing YSZ nanoparticles were recovered.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and nickel in the coated nickel-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.8: 0.2. The absorbance measurement result of the sample obtained by calcining the obtained coated nickel-containing YSZ nanoparticles for 3 hours at 1000 ° C. is as shown in FIG. 8, and the color of the sample was light yellow and uniformly colored. The crystal structure was 100% tetragonal.

Example 3-9
Example 3 was used except that 0.5 g of copper neodecanoate (made by Nippon Kagaku Sangyo Co., Ltd., trade name: copper neodecanoate 5%) was used in place of iron (II) 2-ethylhexanoate in Example 3-1. In the same manner as in Example 1, 18 g of green coated copper-containing YSZ nanoparticles were recovered.

The ratio of tetragonal and monoclinic crystals measured according to “(1) Analysis of crystal structure” is 97/3, and the crystallite diameter measured according to “(3) Calculation of crystallite size by X-ray diffraction analysis” is 5 nm. there were. The weight ratio of zirconium, yttrium, and copper in the coated copper-containing YSZ nanoparticles measured according to “(6) X-ray fluorescence analysis” was 94: 5.7: 0.2. The absorbance measurement results of the sample obtained by calcining the obtained coated cobalt-containing YSZ nanoparticles for 3 hours at 1000 ° C. are as shown in FIG. 8, and the color of the sample was green and uniformly colored. The crystal structure was 100% tetragonal.

Comparative Example 3-1
Production of YSZ Particles Coated with 2-Ethylhexanoic Acid and / or Carboxylate Derived from 2-Ethylhexanoic Acid Example 3 was used except that iron (II) 2-ethylhexanoate was not used. In the same manner as in Example 1, 18 g of white coated YSZ nanoparticles were recovered.

The mass reduction rate of the coated YSZ nanoparticles measured according to “(4) Measurement of weight (mass) reduction rate” was 25% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating the coated YSZ nanoparticles was 25% by mass of the entire coated YSZ nanoparticles.

When the crystal structure of the coated YSZ nanoparticles was measured according to “(1) Analysis of crystal structure” described above, the ratio of tetragonal / monoclinic crystal was 97/3.

Further, the weight ratio of zirconium and yttrium in the coated iron-containing YSZ nanoparticles measured according to the above “(6) X-ray fluorescence analysis” was 94: 5.8.

Further, the sample obtained by firing the obtained coated YSZ nanoparticles at 1000 ° C. has a white color. When the crystal structure is measured according to the above “(1) Analysis of crystal structure”, the ratio of tetragonal crystals is 100. %Met.

Zirconium oxide nanoparticles of the present invention have good dispersibility, such as antireflection films, hard coat films, brightness enhancement films, prism films, lenticular sheets, microlens sheets, and other optical films (or sheets), and optical refractive indices. Conditioner, optical adhesive, optical waveguide, lens, catalyst, CMP polishing composition, electrode, capacitor, ink jet recording method, piezoelectric element, LED / OLED / organic EL light extraction improver, antibacterial agent, dental In addition to good dispersibility, in addition to good dispersibility, the preferred embodiment suppresses changes in the crystal structure before and after firing. It can also be suitably used for ceramic materials such as denture materials. In addition, from the viewpoint of good dispersibility, the zirconium oxide nanoparticles of the present invention are calcined in an embodiment containing Y in particular and at least one selected from the group consisting of Fe, Co, Mn, Ni and Cu. In this case, since it is possible to produce a uniform color and produce a natural color tone, it can be suitably used for ceramic material applications such as ceramic glaze, artificial gems, and dental materials.

Claims (15)

Zirconium oxide nanoparticles coated with a first carboxylic acid that is at least one of a primary carboxylic acid and a secondary carboxylic acid and has 3 or more carbon atoms,
The zirconium oxide nanoparticles contain at least one selected from the group M consisting of rare earth elements, Al, Fe, Co, Sn, Zn, In, Bi, Mn, Ni, and Cu. Nanoparticles. The first carboxylic acid is at least one selected from the group consisting of secondary carboxylic acids, carboxylic acids having branched carbon atoms other than the α-position, and linear carboxylic acids having 4 to 20 carbon atoms. Item 2. The zirconium oxide nanoparticles according to Item 1. The zirconium oxide nanoparticles according to claim 1 or 2, wherein the zirconium oxide nanoparticles contain at least one selected from the group consisting of Y, Al, La, Ce, and In among the elements belonging to the group M. . The zirconium oxide nanoparticles contain Y among elements belonging to the group M, and at least one selected from the group consisting of Fe, Co, Mn, Ni, and Cu. The zirconium oxide nanoparticles described. The zirconium oxide particles, among the elements belonging to the group M, containing at least one element selected from the group M _a consisting rare earth elements and Al, the total content of elements belonging to the group M _a is the group zirconium oxide nanoparticles according to claim 1 or 2 in a ratio to the total content of the elements and zirconium belonging to the M _a is 0.1 mass% or more. Containing the zirconium oxide particles, among the elements belonging to the group M, where La, Ce, Fe, Co, Sn, Zn, In, Bi, Mn, at least one member selected from the group M _b consisting of Ni and Cu and, the total content of elements belonging to the group M _b is, zirconium oxide according to claim 1 or 2 is 0.1 to 20 mass% in a ratio to the total content of the elements and zirconium belonging to the group M _b Nanoparticles. Any of the first carboxylic acid is coated with at least one selected from the group consisting of an organic acid other than the first carboxylic acid, a silane coupling agent, a surfactant, an organic phosphorus compound, and an organic sulfur compound. Zirconium oxide nanoparticles according to the above. The zirconium oxide nanoparticle according to any one of claims 1 to 7, which is a precursor of a sintered zirconium oxide. A dispersion containing the zirconium oxide nanoparticles according to any one of claims 1 to 8. A resin composition comprising the zirconium oxide nanoparticles according to any one of claims 1 to 8. A molding material comprising the zirconium oxide nanoparticles according to any one of claims 1 to 8. A ceramic material obtained from the zirconium oxide nanoparticles according to any one of claims 1 to 8. A method for producing a ceramic material, comprising firing the zirconium oxide nanoparticles according to any one of claims 1 to 8 at 500 ° C or higher. A method for producing a ceramic material, comprising firing the composition containing the zirconium oxide nanoparticles according to any one of claims 1 to 8 at 500 ° C or higher. A method for producing zirconium oxide nanoparticles according to any one of claims 1 to 8,
A zirconium source material composed of the first carboxylic acid and zirconium or a zirconium-containing compound;
A source material of the element belonging to the group M composed of at least one element belonging to the group M and a compound containing the element belonging to the group M, and the first carboxylic acid,
A method for producing zirconium oxide nanoparticles, characterized by hydrothermal synthesis without using MgSO ₄ .

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