JP6796386B2 - Zirconium oxide nanoparticles - Google Patents

Description

The present invention relates to zirconium oxide nanoparticles.

In recent years, metal oxide nanoparticles have been applied in a wide range of fields such as optical materials, pharmaceuticals, ceramics, and electronic materials, and have attracted a great deal of attention. However, the function of single metal oxide nanoparticles is limited, and composite oxide nanoparticles, which may exhibit more specific performance, are attracting attention. In particular, zirconia nanoparticles are expected to be applied to ceramic materials.

For example, Patent Documents 1 to 3 disclose colored stabilized zirconia sintered bodies. In all of Patent Documents 1 to 3, a plurality of types of metal oxides are separately prepared as raw materials, these are mixed by a ball mill or the like, molded, and sintered. However, when multiple kinds of raw materials are prepared separately and mixed, the mixing of different kinds of raw materials is non-uniform, and when a ball mill is used, impurities are mixed from the mill and the particle size is non-uniform. Or become. Ceramics sintered by such a method have problems that transparency is lowered due to grain boundaries and coloration is non-uniform.

Special Table 2010-501465 Japanese Unexamined Patent Publication No. 2012-116745 Japanese Unexamined Patent Publication No. 2013-230981

An object of the present invention is to provide zirconium oxide nanoparticles which are useful as precursors (raw materials) of ceramics having excellent transparency and color uniformity.

The present invention that has achieved the above problems is zirconium oxide nanoparticles coated with carboxylic acid, wherein the zirconium oxide nanoparticles contain yttrium and at least one kind of transition metal other than a rare earth element. Zirconium nanoparticles. The zirconium oxide nanoparticles of the present invention are suitable as precursors for fired zirconium oxide.

The present invention also includes a ceramic material obtained by firing the zirconium oxide nanoparticles. Furthermore, the present invention also includes a method for producing a ceramic material in which the zirconium oxide nanoparticles are fired at 500 ° C. or higher, and a method for producing a ceramic material in which the composition containing the zirconium oxide nanoparticles is fired at 500 ° C. or higher.

According to the present invention, zirconium oxide nanoparticles containing both yttrium and transition metal elements other than rare earth elements and coated with carboxylic acid can be realized, and ceramics fired using such nanoparticles (sintered). Ceramics are also included. The same shall apply hereinafter) is excellent in transparency and color uniformity.

FIG. 1 is a graph showing the absorbance of zirconium oxide ceramics obtained by firing the zirconium oxide nanoparticles of the present invention. FIG. 2 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 a carboxylic acid, they have good dispersibility (including dispersibility in an organic medium such as a solvent or a resin), and are obtained by firing the zirconium oxide nanoparticles of the present invention. The ceramic material to be used has good ceramic properties such as translucency, toughness, and strength. Further, since it contains ittium, the ratio of tetragonal and / or cubic crystals in the crystal structure of the zirconium oxide nanoparticles can be improved, and when the nanoparticles are calcined to obtain a ceramic material, the yttrium is structurally stabilized. It acts as an agent and can suppress changes in the proportion of tetragonal and / or cubic crystals. Further, in the present invention, since the zirconium oxide nanoparticles contain the transition metal, the ceramics obtained by firing the nanoparticles are colored, and the zirconium oxide nanoparticles themselves contain the transition metal, so that the zirconium oxide is zirconium oxide. Compared to the case where and the oxide of the transition metal are prepared separately and mixed and fired, not only the color is uniformly developed, but also the strength of the sintered body is reduced due to the grain boundary with other oxides. It becomes possible to prevent.

The carboxylic acid (hereinafter referred to as the first carboxylic acid) that coats the zirconium oxide nanoparticles of the present invention has 3 or more carbon atoms and 22 or less carbon atoms (preferably 4 or more and 20 or less, more preferably 5 or more and 18 or less). In that case, any of a primary carboxylic acid, a secondary carboxylic acid, and a tertiary carboxylic acid may be used.

Examples of the primary carboxylic acid include a linear primary carboxylic acid and a branched primary carboxylic acid (that is, a carboxylic acid in which carbon atoms other than the 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 the α-position are branched are preferable. The linear carboxylic acid having 4 or more and 20 or less carbon atoms is preferably a linear saturated aliphatic carboxylic acid, and specifically, butyric acid, valeric acid, hexanic acid, heptanic acid, caprylic acid, and nonanoic acid. , Decanoic acid, lauric acid, tetradecanoic acid, stearic acid, oleic acid, ricinoleic acid and the like, preferably caprylic acid, lauric acid, stearic acid, oleic acid, ricinoleic acid and the like. The carboxylic acid in which a carbon atom other than the α-position is branched means a carboxylic acid in which a carboxyl group is bonded to a hydrocarbon group, and the carbon atom other than the α-position of the hydrocarbon group is branched. The carbon number of such a carboxylic acid is preferably 4 to 20, more preferably 5 to 18, for example, isovaleric acid, 3,3-dimethylbutyric acid, 3-methylvaleric acid, isononanoic acid, 4-methylvaleric acid. , 4-Methyl-n-octanoic acid, naphthenic acid and the like.

As the secondary carboxylic acid, a secondary carboxylic acid having 4 to 20 carbon atoms is preferable, a secondary carboxylic acid having 5 to 18 carbon atoms is more preferable, and specifically, isobutyric acid, 2-methylbutyric acid, and 2-ethylbutyric acid. , 2-Ethylhexanoic acid, 2-Methylvaleric acid, 2-Methylhexanoic acid, 2-Methylheptanic acid, 2-propylbutyric acid, 2-Hexyl valeric acid, 2-propylbutyric acid, 2-Hexyldecanoic acid, 2-Heptylundecane Acids, 2-methylhexadecanoic acid, 4-methylcyclohexanecarboxylic acid and the like can be mentioned. Among them, one or more of 2-ethylhexanoic acid and 2-hexyldecanoic acid are preferable, and 2-ethylhexanoic acid is particularly preferable.

As the tertiary carboxylic acid, a tertiary carboxylic acid having 5 to 20 carbon atoms is preferable, and specifically, pivalic acid, 2,2-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-dimethylhexanoic acid, and the like. Examples thereof include 2,2-dimethylheptanic acid and neodecanoic acid.

As the first carboxylic acid, one or more of a primary carboxylic acid and a secondary carboxylic acid are preferable, a carboxylic acid in which carbon atoms other than the α-position are branched, a linear carboxylic acid having 4 to 20 carbon atoms, and 2 It is preferably one or more of the primary carboxylic acids. Of these, as the first carboxylic acid, at least one of a carboxylic acid in which a carbon atom other than the α-position is branched and a secondary carboxylic acid is preferable, and a secondary carboxylic acid is more preferable.

The amount of the first carboxylic acid is, for example, 5 to 40% by mass (preferably 8 to 35% by mass, more preferably 10 to 30% by mass) with respect to the zirconium oxide nanoparticles coated with the first carboxylic acid. %). 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 described above. It should be within the range of.

The zirconium oxide nanoparticles of the present invention are coated with the first carboxylic acid in either a state in which the first carboxylic acid is chemically bonded to the zirconium oxide nanoparticles or a state in which the first carboxylic acid is physically bonded. It also means that it is coated with a first carboxylic acid and / or a carboxylate derived from the first carboxylic acid.

The zirconium oxide nanoparticles of the present invention contain yttrium (for example, as yttria) and have a stable crystal structure in the zirconium oxide crystal. That is, the proportion of tetragonal crystals and / or cubic crystals in the zirconium oxide nanoparticles of the present invention can be increased, and the decrease of tetragonal crystals and / or cubic crystals when the zirconium oxide nanoparticles are fired can be suppressed, and after firing. The proportion of tetragonal and / or cubic can be increased.

The content of yttrium is the total mass of transition metals other than zirconium, yttrium, and rare earth elements in zirconium oxide nanoparticles (hereinafter, "transition metal" is used in the present specification to mean a transition metal excluding rare earth elements). It is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and further preferably 1.5 to 15% by mass. The rare earth element means Sc, Y, and a lanthanoid system (La of atomic number 57 to Lu of atomic number 71). If the amount of yttrium is too small, the stabilizing 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 zirconium oxide nanoparticles of the present invention contain at least one of the transition metals together with yttrium. When the nanoparticles contain a transition metal, the ceramic material obtained by firing the nanoparticles is uniformly colored. As the transition metal, at least one of the transition metals of the 4th period and the 5th period of the periodic table is preferable, and more preferably, the transition metal of the 4th period (that is, Ti, V, Cr, Mn, Fe, Co, Ni, At least one of Cu) is preferable, and at least one of Mn, Fe, Co, Ni, and Cu is more preferable.

The content of the transition metal (the total content when a plurality of types are contained) is 0.05 to 2% by mass, more preferably, as a ratio to the total mass of zirconium, yttrium, and the transition metal in the zirconium oxide nanoparticles. Is 0.1 to 1% by mass, more preferably 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 may not be sufficiently exhibited. On the other hand, if the amount of the transition metal is too large, the stabilizing effect of yttrium is lowered, and the hardness and toughness after firing are affected.

The proportion of zirconium contained in the zirconium oxide nanoparticles of the present invention is, for example, 65% by mass or more, preferably 68% by mass or more, based on the total amount of all metal elements contained in the zirconium nanoparticles. It is 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 (excluding rare earths) may be contained, and such other metal elements usually have a periodic period. These are metal elements from Group 3 onwards. The total amount of other metal elements is, for example, 3% by mass or less, more preferably 2% by mass or less, and 0% by mass, based on the total amount of all metal elements contained in the zirconium nanoparticles. ..

The crystal structure of the zirconium oxide nanoparticles of the present invention is cubic, tetragonal, or monoclinic, and the total of tetragonal and cubic crystals is preferably 80% or more of the entire crystal structure. The ratio of tetragonal crystals and / or cubic crystals is preferably 85% or more, more preferably 90% or more in total of tetragonal crystals and cubic crystals. It may be a tetragonal crystal alone or a cubic crystal alone. Further, since the zirconium oxide nanoparticles of the present invention contain yttrium, tetragonal and / or cubic crystals are stable, and the proportion of tetragonal and / or cubic crystals in the ceramic material obtained by firing 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. The amount of change in the total ratio of tetragonal crystals and cubic crystals before and after calcination is preferably 70% or less, more preferably 30% or less, still more preferably 10% or less with respect to the total ratio of tetragonal crystals and cubic crystals before calcination. 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 tubular shape, a flaky shape, a plate shape, and a flaky shape. Considering the dispersibility in a solvent and the like 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. By doing so, the transparency of the composition containing the zirconium oxide nanoparticles can be improved. In addition, the particles can be expected to reduce the firing temperature and improve the transparency of the fired body. The crystallite diameter is more preferably 20 nm or less, still more preferably 15 nm or less. The lower limit of the crystallite diameter is usually about 1 nm.

The particle size of the zirconium oxide nanoparticles can be evaluated by the average particle size obtained by processing images obtained by various electron microscopes, and the average particle size (average primary particle size) is preferably 50 nm or less. By doing so, the transparency of the composition containing the zirconium oxide nanoparticles can be improved. The average primary particle size is more preferably 30 nm or less, still more 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 is obtained by enlarging 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), or the like, and randomly. It can be determined by selecting 100 particles, measuring their lengths in the long axis direction, and calculating their arithmetic averages.

The zirconium oxide particles of the present invention are organic acids other than the first carboxylic acid, which are obtained after the hydrothermal synthesis reaction and are coated with the first carboxylic acid and further subjected to surface treatment at room temperature or by heating. , Silane coupling agent, surfactant, organic phosphorus compound and the like may be surface-modified. By subjecting the first obtained nanoparticles to surface treatment again, it becomes possible to control the mixability, moldability, etc. with other substances as a firing precursor, and it can be applied to various uses. become. Preferred organic acids, silane coupling agents, surfactants and organic phosphorus compounds will be 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 chemically bonds to the zirconium oxide nanoparticles or forms a carboxylic acid or a salt thereof together with hydrogen atoms and cationic atoms and adheres to the zirconium oxide nanoparticles, the term "coating" is used in the present invention. It includes both a state in which the acid compound is chemically bonded to zirconium oxide and a 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, having 4 to 20 carbon atoms. Hydrocarbons having one or more (preferably one) carboxylic acid groups such as linear carboxylic acid, branched chain carboxylic acid, cyclic carboxylic acid, and aromatic carboxylic acid are preferably adopted.

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

<Silane coupling agent>
As the silane coupling agent, a compound having a hydrolyzable group-Si-OR ₁ (where R ₁ is a methyl group or an ethyl group) is preferable. Examples of such a silane coupling agent include a silane coupling agent having a functional group, an alkoxysilane, and the like.

Examples of the silane coupling agent having a functional group include the following formula (1):
[X- (CH ₂ ) _m ] _4-n- Si- (OR ₁ ) _n ... (1)
(In the formula, X is a functional group, R ₁ 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, a glycidoxy group and the like. Specific examples of the silane coupling agent include a silane coupling agent in which the functional group X such as vinyltrimethoxysilane and vinyltriethoxysilane is a vinyl group; 3-aminopropyltrimethoxysilane and 3-aminopropyltri. Silane coupling in which the functional group X such as ethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltrimethoxysilane is an amino group Agents; functional groups such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane A silane coupling agent in which the group X is a (meth) acryloxy group; a silane coupling agent in which a functional group X such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane is a mercapto group; 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane A silane coupling agent in which the functional group X of the above is a glycidoxy group; and the like.

Examples of the alkoxysilane include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, and decyltrimethoxy. Alkoxy group-containing alkoxysilane in which an alkyl group such as silane is directly bonded to the silicon atom of alkoxysilane; aromatic rings such as phenyltrimethoxysilane, diphenyldimethoxysilane, and p-styryltrimethoxysilane are directly bonded to the silicon atom of alkoxysilane. Alkoxysilanes containing an aryl group that are bonded; and the like.

As the silane coupling agent, among them, a silane coupling agent in which the functional group X is a (meth) acryloxy group and an alkyl group-containing alkoxysilane are preferable, and 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyl are particularly preferable. These are trimethoxysilane, hexyltrimethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane.

The silane coupling agent may be used alone or in combination of two or more. The amount (coating amount) of the silane coupling agent is preferably 0.1 part 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>
Surfactants can improve the transparency and dispersibility of the composition. Further, it is possible to achieve a low viscosity of the composition. As the surfactant, an ionic surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric ionic surfactant, or a nonionic surfactant is preferably used, and an anionic surfactant is preferably used. Examples of the activator include fatty acid sodium such as sodium oleate, sodium stearate, and sodium laurate, fatty acid potassium, fatty acid ester such as sodium sulfonate, phosphoric acid type such as alkyl phosphate sodium, and alpha olein sulfone. Olefin-based surfactants such as sodium acid, alcohol-based surfactants such as sodium alkylsulfate, alkylbenzene-based surfactants, and the like are examples of cationic surfactants such as alkylmethylammonium chloride, alkyldimethylammonium chloride, alkyltrimethylammonium chloride, and alkyldimethylbenzyl chloride. Ammonium and the like can be used as an amphoteric ionic surfactant, for example, a carboxylic acid type such as an alkylaminocarboxylate, a phosphoric acid ester type such as phosphobetaine, and a nonionic surfactant, for example, polyoxyethylene. Examples thereof include fatty acid-based materials such as laurin fatty acid ester and polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, and fatty acid alkanolamide. The surfactant is preferably added in an amount of 0.1% by mass or more and 5% by mass or less with respect to 100% by mass of all the components of the composition.

<Organophosphorus compound>
Examples of the organic phosphorus compound include the following formula:

(In the above formula, p ¹ and p ² are preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30, and even more preferably 4 to 15, respectively, and p ¹ + p. ² is preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30), and examples thereof include phosphoric acid monoesters represented by these) and phosphoric acid diesters having the same substituents. Be done.

In addition, 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 preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30, and even more preferably 4 to 15, respectively. p ¹ + p ² + p ⁵ is preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30, and r and r ² are preferably 1 to 100, more preferably 1 to 50. Yes, more preferably 1 to 20. R ⁴ is a divalent hydrocarbon group having 1 to 18 carbon atoms, or a divalent aromatic-containing hydrocarbon group having 6 to 30 carbon atoms. * Is a phosphorus atom. A compound such as a phosphoric acid monoester or a phosphoric acid diester represented by [at least one selected from the following formulas:

[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 is preferably ¹ to 100, more preferably 1 to 50, still more preferably 1 to 30), and the compound represented by the compound represented by [for example, the following. formula:

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

Examples thereof include various phosphoric acid compounds or phosphoric acid esters represented by.

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

Examples of the above-mentioned organic phosphorus compounds 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 Chemistry Co., Ltd.), and light acrylate P-1A (manufactured by SC Organic Chemistry Co., Ltd.). Kyoeisha Chemical Co., Ltd.), Light Aacrylate P-1M (Kyoeisha Chemical Co., Ltd.), TEGO (registered trademark) Dispers 651, 655, 656 (Ebonic), DISPERBYK-110, 111 (Big Chemie Japan), KAYAMERPM-2 , KAYAMERPM-21 (manufactured by Nippon Kayaku Co., Ltd.) and other commercially available phosphoric acid esters can be appropriately used.

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.

The zirconium oxide nanoparticles of the present invention are coated with the first carboxylic acid by hydrothermally reacting the zirconium component, the yttrium component, the transition metal component, and the first carboxylic acid component, and the transition with the yttrium. Zirconium oxide nanoparticles containing a metal can be obtained. As the zirconium component, a zirconium raw material composed of a first carboxylic acid and a zirconium or a zirconium-containing compound (preferably a conjugate) can be used, and such a zirconium raw material is the first carboxylic acid. It can be said to be an ingredient. Further, as the yttrium component, an yttrium raw material composed of a first carboxylic acid and an yttrium or an yttrium-containing compound (preferably a conjugate) can be used, and such an yttrium raw material is a first carboxylic acid. It can also be said to be an acid component. Further, as the transition metal component, a transition metal raw material composed of a first carboxylic acid and a transition metal or a transition metal-containing compound (preferably a conjugate) can be used, and such a transition metal raw material can be used. Can be said to be the first carboxylic acid component.

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 a first carboxylic acid, and (iii) a first carboxylic acid and oxidation. At least one selected from zirconium precursors can be mentioned.

Examples of the zirconium oxide precursor include zirconium hydroxides, chlorides, oxychlorides, acetates, oxyacetic acids, oxynitrates, sulfates, carbonates, alkoxides 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 that is water-soluble and highly corrosive, such as chloride such as oxychloride of zirconium and nitrate such as oxynitrate, is suitable as a raw material ( The case of i) will be described in detail. The salt is not only a single compound composed of a stoichiometric ratio of a carboxylic acid and a zirconium oxide precursor, but also a composite salt and a composition in which an unreacted carboxylic acid or a zirconium oxide precursor is present. There may be.

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

The degree of neutralization is preferably 0.1 to 0.8, more preferably 0.2 to 0.7. If it is less than 0.1, the salt may not be sufficiently formed due to the low solubility of the first carboxylic acid compound, and if it exceeds 0.8, a large amount of white precipitate presumed to be a hydroxide of zirconium is formed. It may be produced and the yield of coated zirconium oxide particles may decrease. The alkali metal and alkaline earth metal used to obtain the carboxylate-containing composition may be either, but a metal forming a highly water-soluble carboxylate is preferable, and alkali metals, particularly sodium and potassium, are used. Suitable.

The ratio of the carboxylate-containing composition to the zirconium oxide precursor is preferably 1 mol to 20 mol, more preferably 1.2 to 18 mol, with respect to 1 mol of the zirconium oxide precursor. , 1.5 to 15 mol is more preferred. In order to react the carboxylate-containing composition with the zirconium oxide precursor, it is preferable to mix the aqueous solutions with each other or the aqueous solution with an organic solvent. The reaction temperature is not particularly limited as long as it can hold the aqueous solution, but is preferably room temperature to 100 ° C., more preferably 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 preferable.

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 process as described above. However, due to the limited availability of compounds, zirconium oxide particles coated with the desired organic group may not be obtained.

Examples of the zirconium salt that can be used in the embodiment (ii) include zirconium octanate, zirconium 2-ethylhexanate, zirconium stearate, zirconium laurate, zirconium naphthenate, zirconium oleate, and zirconium ricinoleate. Can be done. When the purity of the zirconium salt is low, it may be used after being purified, 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) above 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, and more preferably 1 mol to 8 mol, based on 1 mol of the zirconium oxide precursor. It is preferably 1.2 mol to 5 mol, and more preferably 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 react before the hydrothermal reaction, it is preferable to react the carboxylic acid and the zirconium oxide precursor in a slurry in an organic solvent. At that time, it is preferable to carry out the reaction while removing the water generated during the reaction from the viewpoint of improving the reaction rate and the yield. Since the reaction is carried out 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 for the hydrothermal reaction described later. The reaction temperature is preferably 70 ° C. or higher, more preferably 80 ° C. or higher so that water can be extracted. The upper limit of the reaction temperature is 180 ° C. or lower, more preferably 150 ° C. or lower. If the temperature is too high, side reactions may proceed and carboxylic acid decomposition may occur. If the water cannot be taken out during the reaction, the reaction pressure can be lowered to lower the boiling point of the water for the reaction.

Specifically, as the yttrium raw material, (i) a salt of the first carboxylic acid and the yttrium oxide precursor, (ii) the yttrium salt of the first carboxylic acid, and (iii) the first carboxylic acid and oxidation. At least one selected from yttrium precursors can be mentioned. The preferred embodiments of (i) to (iii) are the same as the preferred embodiments of (i) to (iii) in the zirconium raw material.

Specifically, as the transition metal raw material, (i) a salt of the first carboxylic acid and the transition metal oxide precursor, (ii) the transition metal salt of the first carboxylic acid, and (iii) the first. At least one selected from carboxylic acids and transition metal oxide precursors can be mentioned. The preferred embodiments of (i) to (iii) are the same as the preferred embodiments of (i) to (iii) in the zirconium raw material.

Subsequently, the hydrothermal reaction will be described. First, at least one of the above (i) to (iii) for the zirconium component, at least one of the above (i) to (iii) for the yttrium component, and the above (i) to (iii) for the transition metal component. At least one of the above is preferably mixed in the presence of water. At this time, by heating or under reduced pressure, low boiling point compounds contained in the zirconium oxide precursor such as ammonia and acetic acid can be expelled from the system, and the pressure increase in the hydrothermal reaction in the next step can be suppressed. It is suitable because it can be used. When the viscosity is high and the hydrothermal reaction does not proceed efficiently with only the above (i) to (iii), it is preferable to add an organic solvent showing good solubility in the above (i) to (iii). .. In order to obtain the zirconium oxide nanoparticles of the present invention, in particular, as the zirconium component, the yttrium component, and the transition metal component, the zirconium salt of the first carboxylic acid, the yttrium salt of the first carboxylic acid, and the first carboxylic acid, respectively. It is preferable to use the transition metal salt, that is, to use the aspect (ii) for all of the zirconium component, the yttrium component, and the transition metal component. However, if there is at least one component in which it is difficult to use the aspect (ii) for the zirconium component, the yttrium component, and the transition metal component, of course, even if there is a component used in the aspect (i) or (iii). Well, in such a case, as the mode of the raw material used as the zirconium component, the yttrium component, and the transition metal component, only (ii) and (i), (ii) and (iii) only, (i) only, ( It is preferable that only one of iii) is used. When there are two or more components used in the form of (iii), the oxide precursors of two or more components (that is, the zirconium oxide precursor, the yttrium oxide precursor and the transition metal oxide precursor) are used before the hydrothermal reaction. (2 or more types) and the first carboxylic acid may be mixed to synthesize a raw material containing two or more components 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 the solvent that vaporizes during the hydrothermal reaction may not sufficiently proceed, 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 further 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 thereof include diol, 2,3-butanediol, hexanediol, glycerin, methanetrimethylol, toluene, xylene, trimethylbenzene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO), with dodecane, tetradecane and trimethylbenzene being preferred.

When the two layers are separated by adding the organic solvent, a surfactant or the like may be added to bring them into a uniform phase state or a suspended emulsified state, but usually the two layers are subjected to a hydrothermal reaction as they are. Can be done. The composition may contain a sufficient amount of water derived from the raw material, but if the raw material contains no or little water, the water is added before the hydrothermal reaction. There is a need.

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

The hydrothermal reaction is preferably carried out at a pressure of 2 MPaG (gauge pressure) or less. Although the reaction proceeds even if it exceeds 2 MPaG, it is not industrially preferable because the reactor becomes expensive. On the other hand, if the pressure is too low, the progress of the reaction will be slowed down, the particle size of the nanoparticles may become large due to the reaction for a long time, and zirconium oxide may have a plurality of crystal systems. It is preferably carried out under the above pressure, and more preferably 0.2 MPaG or more. The temperature of the hydrothermal reaction is, for example, 150 to 250 ° C., and 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 a first carboxylic acid and an organic acid other than the first carboxylic acid, first of all, the zirconium oxide nanoparticles coated with the first carboxylic acid. It can be produced by preparing particles and then substituting the first carboxylic acid compound with the organic acid. Specifically, this substitution is carried out by stirring a mixture (particularly a mixed solution) containing the zirconium oxide nanoparticles coated with the first carboxylic acid and the organic acid. The mass ratio of the organic acid to 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. It is possible. The zirconium oxide nanoparticles of the present invention can also be suitably used as a composition containing the nanoparticles. The composition includes a dispersion liquid 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; ethers 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); hydrocarbons such as benzene, toluene, xylene, ethylbenzene, trimethylbenzene, hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, mineral spirits; halogenated hydrocarbons such as dichloromethane, chloroform; dimethylformamide, N, Amids such as N-dimethylacetamide and N-methylpyrrolidone; water; oils such as mineral oil, vegetable oil, wax oil and silicone oil can be mentioned. One of these can be selected and used, or two or more can be selected and used in combination. From the viewpoint of handleability, a solvent having a boiling point of 40 ° C. or higher and 250 ° C. or lower at normal pressure is preferable, 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. , P-methylstyrene, p-chlorostyrene, p-chloromethylstyrene and other styrene-based monomers; carboxyl group-containing monomers such as (meth) acrylic acid; hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate The body etc. can be mentioned. 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). (Meta) acrylic acid alkyl esters such as acrylates, tert-butyl (meth) acrylates, 2-ethylhexyl (meth) acrylates and lauryl (meth) acrylates; (meth) acrylics such as cyclohexyl (meth) acrylates and isobornyl (meth) acrylates. Acid cycloalkyl ester; (meth) acrylate such as benzyl (meth) acrylate; (meth) acrylic acid ester having a glycidyl group such as glycidyl (meth) acrylate may be mentioned, but methyl (meth) acrylate is particularly preferable. .. 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 such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and dipropylene glycol di (meth) acrylate. (Meta) Acrylate: Neopentyl glycol di (meth) acrylate, dineopentyl glycol di (meth) acrylate and other neopentyl glycol poly (meth) acrylate; trimerol propanetri (meth) acrylate, ditrimethylol propanetetra (meth) Trimethylol propanepoly (meth) acrylate such as acrylate; Polyfunctional (meth) acrylate such as pentaerythritol tetra (meth) acrylate, pentaerythritol hexa (meth) acrylate and the like; polyfunctional (meth) acrylate such as divinylbenzene and the like. Polyfunctional styrene-based monomers; Examples thereof include polyfunctional allyl ester-based monomers such as diallyl phthalate, diallyl isophthalate, triallyl cyanurate, and triallyl isocyanurate.

The composition containing the above-mentioned 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. Further, the composition of the present invention may be a resin composition containing the above polymer (resin). When constituting the resin composition of the present invention, the polymer as a medium is, for example, polyamides such as 6-nylon, 66-nylon, and 12-nylon; polyimides; polyurethanes; polyolefins such as polyethylene and polypropylene; PET. , PBT, PEN and other polyesters; polyvinyl chlorides; polyvinylidene chlorides; polyvinyl acetates; polystyrenes; (meth) acrylic resin-based polymers; ABS resins; fluororesins; phenol-formalin resins, cresol-formalin resins Such as phenol resin; epoxy resin; urea resin, melamine resin, amino resin such as guanamine resin and the like can be mentioned. Further, soft resins such as polyvinyl butyral resin, polyurethane resin, ethylene-vinyl acetate copolymer resin, ethylene- (meth) acrylic acid ester copolymer resin, and hard resin are also mentioned. Among the above, polyimides, polyurethanes, polyesters, (meth) acrylic resin-based 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 depending on the intended use, but when the composition is uncured or contains a polymer (resin), the composition is usually used. It is 90% by mass or less with respect to 100% by mass of all the components (total of all the components used among the substitution-coated particles, the solvent, the monomer, the oligomer, the polymer, and the polymer precursor described later). If it exceeds 90% by mass, it becomes difficult to disperse uniformly, and the uncured composition may become cloudy. On the other hand, the lower limit value is not particularly limited, but is, for example, 1% by mass or more in consideration of the solvent cost. It is more preferably 5% by mass or more and 85% by mass or less, and further preferably 10% by mass or more and 80% by mass or less.

The resin composition of the present invention includes not only the composition of the above-mentioned polymer (polymer compound) and the zirconium oxide nanoparticles of the present invention, but also a monomer (polymer precursor) constituting the above polymer, for example. A composition of a mixture of dicarboxylic acid and diamine, unsaturated carboxylic acid such as acrylic acid and methacrylic acid and an ester compound thereof, and zirconium oxide nanoparticles of the present invention is also included. Further, 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), and a molding resin used as a molding material such as an optical film. Is 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 improving the refractive index, for example, and the refractive index can be adjusted according to various uses. When used as a high-concentration zirconium oxide nanoparticles 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 further 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 curable composition after curing) may contain zirconium oxide nanoparticles and other additive components of the resin. Examples of such additive components include curing agents, curing accelerators, colorants, mold release agents, reactive diluents, plasticizers, stabilizers, flame retardant aids, cross-linking agents and the like. The nanoparticles are colored because the transition metal is added, 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 curable composition after curing) is not particularly limited, and may be used as a molding material such as a plate, a sheet, a film, or a fiber.

The zirconium oxide nanoparticles of the present invention have an optical film (or sheet) such as an antireflection film, a hard coat film, a brightness improving film, a prism film, a lenticular sheet, and a microlens sheet, and an optical refractive index because of their good dispersibility. Adjuster, optical adhesive, optical waveguide, lens, catalyst, CMP polishing composition, electrode, capacitor, inkjet recording method, piezoelectric element, light extraction improver such as LED / OLED / organic EL, antibacterial agent, dentistry It is suitably used for adhesives for optical lenses, condensing structures used for solar cell panels, and color filters. In addition, due to its good dispersibility, the zirconium oxide nanoparticles of the present invention can be uniformly colored when fired to give a natural color tone, so that ceramics such as ceramic glazes, artificial jewels, and dental materials can be used. It can also be suitably used for material applications.

Since the zirconium oxide nanoparticles of the present invention contain yttrium, they have a stable crystal structure. That is, when the zirconium oxide nanoparticles of the present invention are fired, changes in the crystal structure can be suppressed, and cracks and a decrease in strength due to changes in the crystal structure can be suppressed. Further, since the zirconium oxide nanoparticles of the present invention are coated with a specific first carboxylic acid, the dispersibility is good, and the ceramic material obtained by firing the zirconium oxide nanoparticles of the present invention is translucent. It has good ceramic properties such as properties, toughness, and strength.

The ceramic material obtained from the zirconium oxide nanoparticles of the present invention can be obtained by firing the zirconium oxide nanoparticles of the present invention alone. Further, the zirconium oxide nanoparticles of the present invention can also be obtained by firing a composition containing additives such as alumina, spinel, YAG, mullite, and aluminum borate compound. Further, the composition composed of the zirconium oxide nanoparticles of the present invention and the binder can be obtained by firing. 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 during firing to promote sintering. Further, it may be fired in air, an oxygen atmosphere, or 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 intended use after firing.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by the following examples, and it is of course possible to carry out the present invention with appropriate modifications within a range that can be adapted to the above-mentioned purpose, and all of them are technical of the present invention. Included in the range.

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

(1) Analysis of Crystal Structure The crystal structure of the zirconium oxide particles was analyzed using an X-ray diffractometer (RINT-TTRIII, manufactured by Rigaku Co., Ltd.). The measurement conditions are as follows.
X-ray source: CuKα (0.154 nm)
X-ray output setting: 50kV, 300mA
Sampling width: 0.0200 ° YSZ
Scan speed: 10.000 ° / min
Measuring range: 10-75 °
Measurement temperature: 25 ° C

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

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

(4) Fluorescent X-ray analysis Using a fluorescent X-ray analyzer (manufactured by ZSX PrimusII Rigaku), the zirconium content, yttrium content, and transition metal content in the coated zirconium oxide particles were measured.

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

Example 1
Production of Iron-Contained Yttria Stabilized Zirconia Particles Coated with Carboxylate Derived from 2-Ethylhexanoic Acid and / or 2-Ethylhexanoic Acid 2-Zirconium Hexanoate Mineral Spirit Solution (83.0 g, Zirconium Content 12% by Mass , Daiichi Rare Element Chemical Industry Co., Ltd.), yttrium 2-ethylhexanate (III) (3.66 g, yttrium content 17% by mass, manufactured by Nippon Chemical Industry Co., Ltd.) and iron 2-ethylhexanate (II) ( 0.35 g, iron content 6% by 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 held at that temperature for 8 hours for reaction. 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 solution was obtained. The solution was depressurized, the organic solvent was removed, and the mixture was dried at 180 ° C. to recover 18 g of pale yellow coated iron-containing yttria-stabilized zirconia nanoparticles. The 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 the above-mentioned "(1) Analysis of crystal structure", the ratio of tetragonal crystals / monoclinic crystals was 97/3. In X-ray diffraction measurement, it is difficult to distinguish between cubic and tetragonal crystals, and even if 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 "(2) 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 the above-mentioned "(3) Measurement of weight (mass) reduction rate" was 25% by mass. Therefore, it was found that the carboxylate derived from 2-ethylhexanoic acid and / or 2-ethylhexanoic acid that coats the coated iron-containing YSZ nanoparticles was 25% by mass of the total amount of the coated iron-containing YSZ nanoparticles.

The weight abundance ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to the above "(4) Fluorescent X-ray analysis" was 94: 5.7: 0.2.

Further, the obtained sample obtained by calcining the coated iron-containing YSZ nanoparticles at 1000 ° C. for 3 hours was yellow as is clear from the result of the absorbance measurement shown in FIG. 1, and was uniformly colored. Further, when the crystal structure was measured according to the above "(1) Analysis of crystal structure", the pattern of FIG. 2 (a) was obtained, which was the same as the tetragonal YSZ (FIG. 2 (b)) shown in the comparative example described later. A pattern was obtained and the proportion of tetragonal crystals was 100%. Note that FIG. 2C is an X-ray diffraction pattern of tetragonal zirconium oxide.

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

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray analysis" was 94: 5.8: 0.1. The obtained sample obtained by calcining the coated iron-containing YSZ nanoparticles at 1000 ° C. for 3 hours had a lighter yellow color than that of Example 1 and was uniformly colored. The crystal structure had a tetragonal proportion of 100%.

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

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray 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 had a deeper yellow color than that of Example 1 described above and had a uniform color. The crystal structure had a tetragonal proportion of 100%.

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

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray analysis" was 94: 5.7: 0.8. The sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles at 1000 ° C. for 3 hours was brown and uniformly colored.

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

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and iron in the coated iron-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray analysis" was 94: 5.6: 1.5. The sample obtained by calcining the obtained coated iron-containing YSZ nanoparticles at 1000 ° C. for 3 hours was brown and uniformly colored.

Example 6
Example 1 and Example 1 except that 0.2 g of cobalt 2-ethylhexanoate (II) (manufactured by Aldrich, 65% mineral spirit solution) was used instead of iron (II) 2-ethylhexanoate in Example 1. Similarly, 18 g of brown coated cobalt-containing YSZ nanoparticles were recovered.

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and cobalt in the coated cobalt-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray analysis" was 94: 5.7: 0.2. The absorbance measurement results of the obtained coated cobalt-containing YSZ nanoparticles calcined at 1000 ° C. for 3 hours were as shown in FIG. 1, and the color of the sample was gray and uniformly colored. The crystal structure had a tetragonal proportion of 100%.

Example 7
Examples except that 0.3 g of manganese 2-ethylhexanoate (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name: Nikkaoctix manganese 8%) was used instead of iron (II) 2-ethylhexanoate in Example 1. In the same manner as in 1, 18 g of purple coated manganese-containing YSZ nanoparticles were recovered.

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and manganese in the coated manganese-containing YSZ nanoparticles measured according to "(4) X-ray fluorescence analysis" was 94: 5.7: 0.2. The absorbance measurement results of the obtained coated manganese-containing YSZ nanoparticles calcined at 1000 ° C. for 3 hours were as shown in FIG. 1, and the color of the sample was gray and uniformly colored. The crystal structure had a tetragonal proportion of 100%.

Example 8
Examples except that 0.2 g of nickel 2-ethylhexanoate (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name: Nikkaoctix Nickel 10%) was used instead of iron (II) 2-ethylhexanoate in Example 1. In the same manner as in 1, 18 g of pale yellow coated nickel-containing YSZ nanoparticles were recovered.

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and nickel in the coated nickel-containing YSZ nanoparticles measured according to "(4) X-ray fluorescence analysis" was 94: 5.8: 0.2. The absorbance measurement results of the obtained sample obtained by calcining the coated nickel-containing YSZ nanoparticles at 1000 ° C. for 3 hours were as shown in FIG. 1, and the color of the sample was pale yellow and uniformly colored. The crystal structure had a tetragonal proportion of 100%.

Example 9
Same as in Example 1 except that 0.5 g of copper neodecanoate (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name: copper neodecanoate 5%) was used instead of iron (II) 2-ethylhexanoate in Example 1. Then, 18 g of green coated copper-containing YSZ nanoparticles were recovered.

The ratio of tetragonal crystals to monoclinic crystals measured according to "(1) Analysis of crystal structure" is 97/3, and the crystallite diameter measured according to "(2) Calculation of crystallite size by X-ray diffraction analysis" is 5 nm. there were. The weight abundance ratio of zirconium, yttrium, and copper in the coated copper-containing YSZ nanoparticles measured according to "(4) Fluorescent X-ray analysis" was 94: 5.7: 0.2. The absorbance measurement results of the obtained coated cobalt-containing YSZ nanoparticles calcined at 1000 ° C. for 3 hours were as shown in FIG. 1, and the color of the sample was green and uniformly colored. The crystal structure had a tetragonal proportion of 100%.

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

The mass reduction rate of the coated YSZ nanoparticles measured according to the above-mentioned "(3) Measurement of weight (mass) reduction rate" was 25% by mass. Therefore, it was found that the carboxylate derived from 2-ethylhexanoic acid and / or 2-ethylhexanoic acid that coats the coated YSZ nanoparticles was 25% by mass of the total amount of the coated YSZ nanoparticles.

When the crystal structure of the coated YSZ nanoparticles was measured according to the above-mentioned "(1) Analysis of crystal structure", the ratio of tetragonal / monoclinic crystals was 97/3.

The weight abundance ratio of zirconium and yttrium in the coated iron-containing YSZ nanoparticles measured according to the above "(4) Fluorescent X-ray analysis" was 94: 5.8.

Further, the obtained coated YSZ nanoparticles fired at 1000 ° C. had a white color, and the crystal structure thereof was measured according to the above "(1) Analysis of crystal structure". As a result, the ratio of tetragonal crystals was 100. %Met.

Claims (6)

Zirconium oxide nanoparticles coated with carboxylic acid
The zirconium oxide nanoparticles are zirconium oxide nanoparticles containing yttrium and at least one of a transition metal other than a rare earth element. Claim that the average primary particle diameter is 50 nm or less, and the content of the transition metal is 0.05 to 2% by mass as a ratio to the total mass of zirconium, yttrium, and the transition metal in the zirconium oxide nanoparticles. The zirconium oxide nanoparticles according to 1 . The zirconium oxide nanoparticles according to claim 1 or 2, which is a precursor of a fired zirconium oxide product. A ceramic material obtained by firing the zirconium oxide nanoparticles according to any one of claims 1 to 3. A method for producing a ceramic material, wherein the zirconium oxide nanoparticles according to any one of claims 1 to 3 are fired at 500 ° C. or higher. A method for producing a ceramic material, wherein the composition containing the zirconium oxide nanoparticles according to any one of claims 1 to 3 is fired at 500 ° C. or higher.

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