Composition

Abstract

To provide a composition which contains a phosphorus-based dispersant, metal oxide particles and a dispersion medium, and has good compatibility between the metal oxide particles and the dispersion medium.SOLUTION: A composition comprises: metal oxide particles having an average primary particle diameter of 50 nm or less; a dispersant containing a phosphoric acid compound; and at least one type of solvent and monomer, wherein the composition may contain phosphoric acid, and the amount of phosphoric acid is 0.60 mass% or less, relative to 100 mass% of the metal oxide particles.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition, and more particularly to a composition containing metal oxide particles.

Background Art

[0002] Nanoparticle-containing compositions such as resin compositions and curable compositions containing various metal oxide nanoparticles can contribute to the high functionality and high performance of various materials such as optical materials, electronic component materials, magnetic recording materials, catalyst materials, ultraviolet absorption materials, and dental materials according to the functions of the nanoparticles. However, since the dispersibility of metal oxide nanoparticles alone in an organic medium is insufficient, they often aggregate, causing problems such as a decrease in transparency.

[0003] Therefore, in Patent Document 1, metal oxide particles having an average primary particle diameter of 50 nm or less are dispersed in a dispersion medium together with an organic acid and a predetermined organic phosphorus compound or a salt thereof. The dispersion obtained in this way is said to have good compatibility.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even when metal oxide particles are dispersed using a predetermined organic phosphorus compound as in Patent Document 1, sufficient compatibility may not be obtained, and particularly when the concentration of the organic phosphorus compound is increased, the tendency of compatibility to decrease becomes remarkable. [[ID=4 0]]

[0006] Therefore, an object of the present invention is to provide a composition containing a phosphorus-based dispersant, metal oxide particles, and a dispersion medium, and having good compatibility between the metal oxide particles and the dispersion medium.

Means for Solving the Problems

[0007] The present invention that achieves the above problems is as follows. [1] A composition comprising metal oxide particles having an average primary particle diameter of 50 nm or less, a dispersant containing a phosphate compound, and at least one of a solvent and a monomer, wherein the composition may contain phosphoric acid, and the amount of the phosphoric acid is 0.60% by mass or less based on 100% by mass of the metal oxide particles. [2] The composition according to [1], wherein the metal oxide particles are coated with the dispersant. [3] The composition according to [1] or [2], wherein the phosphate compound is at least one of a phosphate ester represented by the following formula (p1) or a salt thereof. [Chemical formula] In the above formula (p1), R 1 is a linear or branched alkyl group having 1 to 10 carbon atoms, R 2 is a linear or branched alkylene group having 2 to 4 carbon atoms, n is 1 to 10, and a is 1 to 3. [4] The composition according to [3], wherein the phosphate compound contains a phosphoric acid monoester in which a is 1 in the above formula (p1) and a phosphoric acid diester in which a is 2 in the above formula (p1). [[ID=三十]] [5] The composition according to any one of [1] to [4], wherein the ratio (P / M) of the mass (P) of phosphorus atoms on the surface of the metal oxide particles to the mass (M) of metal atoms of the metal oxide particles is 0.001 to 0.1. [6] A cured product of the composition according to any one of [1] to [5] containing a monomer. [Advantages of the Invention]

[0008] The composition containing the metal oxide particles of the present invention contains a dispersant containing a phosphate compound, and does not contain phosphoric acid in the composition or contains a small amount of phosphoric acid if it is contained, so that a composition having good compatibility between the metal oxide particles and the dispersion medium can be obtained. [Modes for carrying out the invention]

[0009] The present invention relates to a composition comprising metal oxide particles having an average primary particle diameter of 50 nm or less, a dispersant containing a phosphoric acid compound, and at least one of a solvent and a monomer, wherein the composition may contain phosphoric acid, and the amount of phosphoric acid is 0.60% by mass or less per 100% by mass of the metal oxide particles. In this document, a phosphoric acid compound means a compound to which phosphoric acid is bonded with one or more elements, and does not include phosphoric acid itself (H3PO4).

[0010] 1. Metal oxide particles Examples of metal oxide particles include oxide particles of Ti, Al, Zr, In, Zn, Sn, La, Y, Ce, Mg, Ba, Ca, Sb, etc., and from the viewpoint of increasing the refractive index, it is preferable that the particles be at least one oxide particle selected from the group consisting of Ti, Al, Zr, Zn, Sn, and Ce, and more preferably Zr oxide particles, i.e., zirconium oxide (ZrO2) particles. The metal oxide may be an oxide of a single metal, a solid solution of two or more oxides, or a composite oxide. Examples of single metal oxides include aluminum oxide (Al2O3), titanium oxide (TiO2), zirconium oxide (ZrO2), indium oxide (In2O3), zinc oxide (ZnO), tin oxide (SnO2), lanthanum oxide (La2O3), yttrium oxide (Y2O3), cerium oxide (CeO2), magnesium oxide (MgO), barium oxide (BaO), calcium oxide (CaO), and antimony oxide (Sb2O3). Examples of solid solutions of two or more oxides include indium tin oxide (ITO) and tin-antimony oxide (ATO). Examples of complex oxides include barium titanate (BaTiO3), titanite (CaTiO3), and spinel (MgAl2O4).

[0011] The crystallite size of the metal oxide particles is preferably 20 nm or less, more preferably 15 nm or less, and even more preferably 10 nm or less, and is usually 1 nm or more. The smaller the crystallite size, the higher the light transmittance of the composition containing the metal oxide particles. The crystallite size can be determined by X-ray diffraction.

[0012] The crystal structure of the metal oxide particles can be determined by X-ray diffraction, and is preferably cubic, tetragonal, or monoclinic, and multiple crystal structures may be present. However, it is difficult to distinguish between cubic and tetragonal metal oxide particles in X-ray diffraction measurements, and even if cubic particles are present, their proportion is counted as the proportion of tetragonal particles. From the viewpoint of improving the refractive index, it is preferable that 50% or more of the total crystal structure is tetragonal and / or cubic. Furthermore, the ratio of the total tetragonal and cubic crystals to monoclinic crystals ((tetragonal + cubic) / monoclinic) is preferably 1.0 or more, more preferably 1.1 or more, and may also be 5 or less.

[0013] Furthermore, the average primary particle diameter of the metal oxide particles is preferably 50 nm or less, more preferably 30 nm or less, even more preferably 20 nm or less, preferably 1 nm or more, and more preferably 5 nm or more. When the average primary particle diameter of the metal oxide particles is within the above range, it becomes easier to improve the transparency of the metal oxide particle-containing composition. The average primary particle diameter can be determined by observing the metal oxide particles under magnification using a transmission electron microscope (TEM), field emission transmission electron microscope (FE-TEM), field emission scanning electron microscope (FE-SEM), etc., randomly selecting 100 particles, measuring their length in the longitudinal direction, and calculating the arithmetic mean.

[0014] The amount of metal oxide particles is usually 10 to 80% by mass of the composition. In particular, when the dispersion medium is a solvent, the amount of metal oxide particles is preferably 60 to 80% by mass; when the dispersion medium is a monomer, the amount of metal oxide particles is preferably 40 to 60% by mass; and when the dispersion medium contains both a solvent and a monomer, the amount of metal oxide particles is preferably 10 to 30% by mass. If the metal oxide particles are coated with a dispersant or a surface treatment agent, the amount of metal oxide particles as described above also includes the amount of the dispersant and surface treatment agent coating.

[0015] 2. Dispersant The dispersant in the present invention is a phosphorus-based dispersant containing a phosphorus compound, characterized in that it contains no phosphorus or, if present, only a small amount of phosphorus. By using a dispersant with a low phosphorus content, the amount of phosphorus in the composition containing this phosphorus-based dispersant can also be reduced, resulting in good compatibility between metal oxide particles and the dispersion medium. The amount of phosphorus per 100% by mass of the dispersant is preferably less than 2.5% by mass, more preferably 2.0% by mass or less, even more preferably 1.6% by mass or less, and particularly preferably 1.5% by mass or less. The lower limit of the amount of phosphorus is not particularly limited and may be 0% by mass or 0.2% by mass.

[0016] The phosphate compound is preferably a phosphate ester, and may be a monophosphate ester, diphosphate ester, triester phosphate, or a mixture of two or more of these, with a particular preference for the inclusion of monophosphate and diphosphate esters. The phosphate compound is preferably a phosphate ester having an alkylene oxide unit, and is particularly preferably an ester of phosphoric acid with a polyalkylene glycol monoalkyl ether, for example, at least one of a phosphate ester or salt thereof represented by the following formula (p1).

[0017] [ka]

[0018] In the above formula (p1), R 1 R is a linear or branched alkyl group having 1 to 10 carbon atoms. 2 is a linear or branched alkylene group having 2 to 4 carbon atoms, where n is 1 to 10 and a is 1 to 3.

[0019] R 1 It is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and more preferably a linear alkyl group having 1 to 3 carbon atoms. 2 It is more preferable that the group is a linear alkylene group having 2 to 4 carbon atoms. n is preferably 1 to 8, and more preferably 1 to 4.

[0020] The above phosphate compound preferably includes a phosphate monoester in which a is 1 in formula (p1) and a phosphate diester in which a is 2 in formula (p1). In this case, R 1 , R 2 The value of n may be the same for the phosphate monoester and the phosphate diester, or it may be different, but it is preferable that they be the same. When the phosphate compound contains the above-mentioned phosphate monoester and phosphate diester, the amount of phosphate monoester / phosphate diester is preferably 20 / 80 to 80 / 20 by mass ratio, and more preferably 30 / 70 to 70 / 30.

[0021] The amount of phosphoric acid compound in the composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 13.5% by mass or more, and may also be 30% by mass or less, based on 100% by mass of metal oxide particles. Note that if the metal oxide particles are coated with a dispersant or surface treatment agent, the amount of coating is not included in 100% by mass of metal oxide particles when determining the amount of phosphoric acid compound. Furthermore, if the phosphoric acid compound contains multiple types of phosphoric acid compounds, the amount of phosphoric acid compound refers to the total amount.

[0022] As described above, the low-phosphate dispersant used in the present invention can be manufactured in the following manner. Generally, a method for obtaining a dispersant containing a phosphate ester involves reacting an organic hydroxy compound with a phosphorylating agent. Examples of phosphorylating agents include polyphosphate, phosphorus pentoxide, and phosphorus oxychloride. A specific manufacturing method is described in Japanese Patent Publication No. 2007-197417. A dispersant containing a low-phosphate phosphate ester can be obtained by reacting an organic hydroxy compound with low water content with at least one of the phosphorylating agents described above. The water content at that time should preferably be 0.3% or less relative to the organic hydroxy compound. Alternatively, the synthesized phosphate ester can be obtained by purification such as washing with water.

[0023] It is preferable that the metal oxide particles are coated with a dispersant containing a phosphoric acid compound. The ratio of the amount of phosphoric acid (P0) to the amount of phosphoric acid (P1) contained in the coating layer of the metal oxide particles (P0 / P1) is preferably 0.060 or less, more preferably 0.05 or less, and the lower limit may be 0 or 0.003. That is, the composition of the present invention is a composition comprising metal oxide particles having an average primary particle diameter of 50 nm or less, a solvent and at least one monomer, wherein the metal oxide particles are coated with a dispersant containing a phosphoric acid compound, the dispersant may contain phosphoric acid, and it is also preferable that the ratio of the amount of phosphoric acid (P0) to the amount of phosphoric acid (P1) contained in the coating layer of the metal oxide particles (P0 / P1) is 0.060 or less.

[0024] When the phosphoric acid compound includes a monophosphate ester in formula (p1) where a is 1 and a diphosphate ester in formula (p1) where a is 2, it is preferable that the ratio of the amount of diphosphate ester (P12) to the amount of monophosphate ester (P11) contained in the coating layer of metal oxide particles (P12 / P11) is 20 / 80 to 80 / 20, and the ratio of the amount of phosphoric acid (P0) to the amount of monophosphate ester (P11) (P0 / P11) is 0.01 to 0.10. The value of P12 / P11 is more preferably 30 / 70 or higher, and more preferably 70 / 30 or lower. The value of P0 / P11 is more preferably 0.02 or higher, and more preferably 0.09 or lower.

[0025] When metal oxide particles are coated with a dispersant containing a phosphoric acid compound, the phosphoric acid compound is preferably 5% by mass or more, and more preferably 10% by mass or more, relative to 100% by mass of the coated metal oxide particles. As described above, the dispersant used in the present invention has a reduced phosphoric acid content, so even if the amount of phosphoric acid compound in the coating layer exceeds a predetermined level, the compatibility between the metal oxide particles and the dispersion medium does not decrease, and it is also expected that the storage stability of the composition containing the metal oxide particles, dispersion medium and dispersant will be improved. The upper limit of the amount of phosphoric acid compound is not particularly limited, but the amount of phosphoric acid compound may be 25% by mass or less, or 20% by mass or less. The amount of coated metal oxide particles (sometimes called coated metal oxide particles) also includes the amount of dispersant containing a phosphoric acid compound and the surface treatment agent described later. The amount of phosphoric acid compound can be calculated from the weight loss rate when the coated metal oxide particles are heated from room temperature to 800 degrees Celsius and the amount of carboxylic acid in the coated metal oxide particles measured by gas chromatography, as shown in the examples described later.

[0026] Furthermore, whether the amount of phosphorus compound in the coating layer is above a predetermined level can also be evaluated by the ratio (P / M) of the mass of phosphorus atoms on the surface of the metal oxide particles to the mass (M) of the metal atoms in the metal oxide particles, where the value of P / M is preferably 0.001 or higher, more preferably 0.01 or higher, and may also be 0.1 or lower.

[0027] 3. Surface treatment agent The composition of the present invention preferably contains at least one of a carboxylic acid compound, a silane coupling agent, a surfactant, and a titanium coupling agent, and preferably contains at least a carboxylic acid compound, and preferably the metal oxide particles are coated with at least a carboxylic acid compound.

[0028] The amount of surface treatment agent per 100% by mass of coated metal oxide particles is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and may also be 7% by mass or less, or 5% by mass or less. In the coating layer of metal oxide particles, the mass ratio of the surface treatment agent to the phosphoric acid compound is preferably 0.03 or more, more preferably 0.05 or more, preferably 0.5 or less, and more preferably 0.3 or less. When two or more types of surface treatment agents are used, the amount of surface treatment agent refers to the total amount.

[0029] 3-1. Carboxylic Acid Compounds Carboxylic acid compounds are compounds having one or more carboxyl groups (-COOH) or one or more carboxylate groups (-COO-). Compounds having one or more carboxyl groups include linear saturated aliphatic carboxylic acids such as oxalic acid, malonic acid, butyric acid, succinic acid, valeric acid, glutaric acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, palmitic acid, and stearic acid; branched saturated aliphatic carboxylic acids that are primary carboxylic acids such as isovaleric acid, 3,3-dimethylbutyric acid, 3,3-diethylbutyric acid, 3-methylvaleric acid, isononanoic acid, 4-methylvaleric acid, and 4-methyloctanoic acid; and isobutyric acid and 2-methylbutyric acid. Branched-chain saturated aliphatic carboxylic acids, which are secondary carboxylic acids such as 2-ethylbutyric acid, 2-ethylhexanoic acid, 2-methylvaleric acid, 2-methylhexanoic acid, 2-methylheptanoic acid, 2-propylbutyric acid, 2-hexylvaleric acid, 2-hexyldecanoic acid, 2-heptylundecanoic acid, and 2-methylhexadecanoic acid; branched-chain saturated aliphatic carboxylic acids, which are tertiary carboxylic acids such as pivalic acid, 2,2-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-diethylbutyric acid, 2,2-dimethylhexanoic acid, and neodecanoic acid; naphthenic acid, cyclohex Alicyclic hydrocarbon group-containing carboxylic acids such as diadicarboxylic acid; linear unsaturated aliphatic carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, oleic acid, linoleic acid, and linolenic acid; ether-linked carboxylic acids such as methoxyacetic acid, ethoxyacetic acid, 3-ethoxypropionic acid, 2-methoxyethoxyacetic acid, and 2-methoxyethoxyethoxyacetic acid; lactic acid, malic acid, citric acid, hydroxystearic acid, glycolic acid, DL-lactic acid, 2-hydroxyisobutyric acid, dimethylolpropionic acid, hydroxypivalic acid, 3-hydroxypropionic acid, DL-2-hydroxybutyric acid, DL-3-hydroxybutyric acid, 2-hydroxy-2-methylbutyric acid, β-hydroxyisovaleric acid, 2,2-bis(hydroxymethyl)butyric acid, serine, threonine, 4-hydroxycyclohexanecarboxylic acid, (o-,m-,p-)hydroxybenzoic acid, and other hydroxyl group-containing carboxylic acids; glyoxylic acid, pyruvic acid, levulinic acid, 2-oxovaleric acid, asparagine, glutamine, β-methyllevulinic acid, α-methyllevulinic acid, and other carbonyl group-containing carboxylic acids;Examples include aromatic carboxylic acids such as benzoic acid, phthalic acid, and isophthalic acid; (meth)acryloyl group-containing carboxylic acids such as 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, and 2-methacryloyloxyethyl phthalic acid; sulfide bond-containing carboxylic acids such as methionine and phenylthioacetic acid; -NH2 group-containing carboxylic acids such as glycine, alanine, 2-methylalanine, cysteine, serine, threonine, valine, leucine, isoleucine, methionine, and lysine; carbamoyl group-containing carboxylic acids such as asparagine and glutamine; dicarboxylic acids such as aspartic acid and glutamic acid; cyano group-containing carboxylic acids such as cyanoacetic acid; and heterocyclic compounds substituted with carboxyl groups such as proline.

[0030] Compounds having one or more carboxylate groups (-COO-) may be polycarboxylic acid anhydrides and / or hydrolysates of these acid anhydrides. Examples of polycarboxylic acid anhydrides include 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, hexahydrophthalic anhydride, trimellitic anhydride, hexahydro-4,7-methanoisobenzofuran-1,3-dione, 1,2,3,6-tetrahydrophthalic anhydride, and ethylene glycol. Bis-anhydrotrimellitate 1,2,3,4-butanetetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, methylcyclohexene-1,2-dicarboxylic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, ethylenediaminetetraacetic acid dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, tricyclo[6.4.0.02,7] Dodecane-1,8:2,7-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 3-(carboxymethyl)-1,2,4-cyclopentanetricarboxylic acid 1,4:2,3-dianhydride, pyromellitic anhydride, 4,4'-carbonyl diphthalic anhydride, phthalic anhydride, naphthalene-1,4,5, 8-tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride, maleic anhydride, 4,4'-biphthalic anhydride, 3,4'-oxydiphthalic anhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 3,4'-biphthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, acetic anhydride, benzoic anhydride, propionic anhydride, oxalic anhydride, phthalic anhydride, pyromellitic dianhydride, 2 -Octenyl succinic anhydride, hexadecyl succinic anhydride, isooctadecenyl succinic anhydride, octadecyl succinic anhydride, decenyl succinic anhydride, [(3-triethoxysilyl)propyl] succinic anhydride, decyl succinic anhydride, butyl succinic anhydride, n-octyl succinic anhydride, tetradecenyl succinic anhydride, dodecyl succinic anhydride, tetradecyl succinic anhydride, 2-dodecen-1-yl succinic anhydride, 2-hexen-1-yl succinic anhydride, [3-(trimethoxy Examples include silyl)propyl succinic anhydride, phenyl succinic anhydride, hexadecenyl succinic anhydride, 2,2-dimethyl succinic anhydride, octadecenyl succinic anhydride, (2,7-octadien-1-yl) succinic anhydride, isooctadecylsuccinic anhydride, 4-hexen-1,2-dicarboxylic acid anhydride, itaconic acid anhydride, allyl succinic anhydride, (2-methyl-2-propenyl) succinic anhydride, octenyl succinic anhydride, tetrapropenyl succinic anhydride, and succinic anhydride.

[0031] As the carboxylic acid compound, it is preferable that a branched saturated aliphatic carboxylic acid is included, or an acid anhydride of a polyvalent carboxylic acid and / or a hydrolyzate of the acid anhydride is included. It is preferable to include at least a branched saturated aliphatic carboxylic acid, and it is more preferable to include a branched saturated aliphatic carboxylic acid which is at least a secondary carboxylic acid. Here, the secondary carboxylic acid means a carboxylic acid in which the carbon bonded to the carboxyl group is a secondary carbon.

[0032] The amount of the carboxylic acid compound with respect to 100% by mass of the coated metal oxide particles is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and may be 5% by mass or less, or may be 3% by mass or less. In the coating layer of the metal oxide particles, the mass ratio of the carboxylic acid compound to the phosphoric acid compound is preferably 0.01 or more, more preferably 0.05 or more, preferably 0.4 or less, and more preferably 0.3 or less.

[0033] 3-2. Silane coupling agent One kind or two or more kinds of silane coupling agents can be used, and a compound having a functional group -Si-OR 9 (where R 9 is a methyl group or an ethyl group) is preferable. Examples of the silane coupling agent include a silane coupling agent having a functional group and an alkoxysilane.

[0034] Examples of the silane coupling agent having a functional group include the following formula (3): [X-(CH2) m 4-n -Si-(OR 9 ) n …(3) (In the formula, X is a functional group, R 9 is the same as above, m represents an integer of 0 to 4, and n represents an integer of 1 to 3.) The silane coupling agent represented by the formula can be mentioned.

[0035] ​Examples of X include vinyl groups, amino groups, (meth)acryloxy groups, mercapto groups, and glycidoxy groups. Specific examples of silane coupling agents include, for example, silane coupling agents where the functional group X is a vinyl group, such as vinyltrimethoxysilane and vinyltriethoxysilane; silane coupling agents where the functional group X is an amino group, such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-2-(aminoethyl)-3-aminopropylmethyltrimethoxysilane; and 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyldi Examples include silane coupling agents in which the functional group X is a (meth)acryloxy group, such as methoxysilane and 3-methacryloxypropylmethyldiethoxysilane; silane coupling agents in which the functional group X is a mercapto group, such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; and silane coupling agents in which the functional group X is a glycidoxy group, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane.

[0036] Examples of alkoxysilanes include alkyl-containing alkoxysilanes in which alkyl groups such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane are directly bonded to the silicon atom of the alkoxysilane; and aryl-containing alkoxysilanes in which aromatic rings such as phenyltrimethoxysilane, diphenyldimethoxysilane, and p-styryltrimethoxysilane are directly bonded to the silicon atom of the alkoxysilane.

[0037] Preferred silane coupling agents include silane coupling agents in which the functional group X is a (meth)acryloxy group and alkyl group-containing alkoxysilanes, with 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, hexyltrimethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane being more preferred.

[0038] 3-3. Surfactants Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of anionic surfactants include fatty acid-based surfactants such as sodium oleate, sodium stearate, sodium laurate, potassium fatty acid, and sodium fatty acid ester sulfonate; phosphoric acid-based surfactants such as sodium alkyl phosphate; olefin-based surfactants such as sodium alpha-olefin sulfonate; alcohol-based surfactants such as sodium alkyl sulfate; and alkylbenzene-based surfactants. Examples of cationic surfactants include alkylmethylammonium chloride, alkyldimethylammonium chloride, alkyltrimethylammonium chloride, and alkyldimethylbenzylammonium chloride. Examples of amphoteric surfactants include carboxylic acid-based surfactants such as alkylaminocarboxylates and phosphate esters such as phosphobetaine. Examples of nonionic surfactants include fatty acid-based surfactants such as polyoxyethylene lauric acid fatty acid ester and polyoxyethylene sorbitan fatty acid ester; polyoxyethylene alkylphenyl ethers; and fatty acid alkanolamides.

[0039] 3-4. Titanium coupling agent Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl tri(dodecyl)benzenesulfonyl titanate, neopentyl(diallyl)oxy-tri(dioctyl) phosphate titanate, and neopentyl(diallyl)oxy-trineododecanoyl titanate.

[0040] In the present invention, when the metal oxide particles are coated with both the dispersant and the surface treatment agent as described above, the total amount of the dispersant and the surface treatment agent relative to 100% by mass of the coated metal oxide particles is, for example, 8% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, and more preferably 25% by mass or less.

[0041] 4. Solvent Because the composition of the present invention contains a dispersant comprising the above-mentioned phosphoric acid compound, the metal oxide particles have good compatibility with the solvent, and the metal oxide particles can be well dispersed in the composition containing the solvent. Examples of solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 1-methoxy-2-propanol, and ethylene glycol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate and propyl acetate; ethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether; modified ethers such as propylene glycol monomethyl ether acetate (especially ether-modified and / or ester-modified alkylene glycols); hydrocarbons such as benzene, toluene, xylene, ethylbenzene, hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, and mineral spirits; halogenated hydrocarbons such as dichloromethane and chloroform; amides such as dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; water; and oils such as mineral oil, vegetable oil, wax oil, and silicone oil. These may be used individually or in combination of two or more. From a handling standpoint, solvents with a boiling point of approximately 40°C to 250°C at atmospheric pressure (1013 hPa) are preferred. The solvent is preferably at least one of alcohols, esters, ketones, and modified ethers.

[0042] 5. Monomer Furthermore, since the composition of the present invention contains a dispersant containing the above-mentioned phosphoric acid compound, the compatibility between the metal oxide particles and the monomer is also good, and the metal oxide particles can be well dispersed in the composition containing the monomer. Examples of monomers include monofunctional monomers having one polymerizable double bond or crosslinkable monomers having two or more polymerizable double bonds. Monomers can be used individually or in combination of two or more.

[0043] Examples of monofunctional monomers include (meth)acrylic acid esters; styrene monomers such as styrene, ptert-butylstyrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-chlorostyrene, and p-chloromethylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid; and hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxy-2-hydroxypropyl (meth)acrylate, and 3-phenoxy-2-hydroxypropyl (meth)acrylate. Among these, monofunctional (meth)acrylic acid esters are preferred.

[0044] Monofunctional (meth)acrylic acid esters include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; and cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. Steryl esters; aryl esters of (meth)acrylate such as 2,4-dibromo-6-sec-butylphenyl(meth)acrylate, 2,4-dibromo-6-isopropylphenyl(meth)acrylate, phenyl(meth)acrylate, 2,4,6-tribromophenyl(meth)acrylate, pentabromophenyl(meth)acrylate; aralkyl esters of (meth)acrylate such as benzyl(meth)acrylate and pentabromobenzyl(meth)acrylate; phenoxyethyl(meth)acrylate (meth)acrylic acids having aryloxy units, such as phenoxy-2-methylethyl (meth)acrylate, 2,4,6-tribromophenoxyethyl (meth)acrylate, 2,4-dibromophenoxyethyl (meth)acrylate, 2-bromophenoxyethyl (meth)acrylate, 1-naphthyloxyethyl (meth)acrylate, 2-naphthyloxyethyl (meth)acrylate, phenoxy-2-methylethyl (meth)acrylate, and phenoxyethoxyethyl (meth)acrylate. Examples include esters; (meth)acrylic acid esters having an arylthiooxy group, such as phenylthioethyl (meth)acrylate, 1-naphthylthioethyl (meth)acrylate, and 2-naphthylthioethyl (meth)acrylate; alkylene glycol mono(meth)acrylates, such as methoxypolyethylene glycol (meth)acrylate and phenoxypolyethylene glycol (meth)acrylate; and (meth)acrylic acid esters having a glycidyl group, such as glycidyl (meth)acrylate. R contained in the above compound y1 -O-(R y2 -O-) n - Unit (R y1R represents a methyl group and a phenyl group. y2 represents an ethylene group. n represents an integer. ) is R y1 -(O) ty -L y - Unit (ty represents an integer of 0 or 1, L y ) may be substituted with R y1 -O-(CH2CH2-O-) ny -The unit (ny represents an integer between 1 and 30) is preferable. Examples of crosslinkable monomers include crosslinkable (meth)acrylic acid esters; polyfunctional styrene monomers such as divinylbenzene; polyfunctional allyl ester monomers such as diallyl phthalate, diallyl isophthalate, triallyl cyanurate, and triallyl isocyanurate; 2-(2-vinyloxyethoxy)ethyl (meth)acrylate; and urethane acrylate oligomers (for example, the Shiko® series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), the CN series (manufactured by Sartomer Co., Ltd.), the Unidick® series (manufactured by DIC Corporation), the Kayarad® UX series (manufactured by Nippon Kayaku Co., Ltd.), etc.), among which crosslinkable (meth)acrylic acid esters are preferred.

[0045] Examples of crosslinkable (meth)acrylic acid esters include alkylene glycol poly(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, etc.; neopentyl glycol poly(meth)acrylates such as neopentyl glycol di(meth)acrylate, dineopentyl glycol di(meth)acrylate, etc.; trimethylolpropane tri(meth)acrylate, ethoxylated (3) trimethylolpropane Examples include trimethylolpropane poly(meth)acrylates such as methyl(meth)acrylate, propoxylated(3)trimethylolpropane tri(meth)acrylate, and ditrimethylolpropanetetra(meth)acrylate; glyceryl poly(meth)acrylates such as glyceryl tri(meth)acrylate and ethoxylated glyceryl tri(meth)acrylate; pentaerythritol poly(meth)acrylates such as pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; and alkyl esters of α-allyloxymethylacrylate such as α-allyloxymethylacrylate. R contained in the above compound z1 -O-(R z2 -O-) n - Unit (R z1 R represents a (meth)acryloyl group. z2 represents an ethylene group or a propylene group. n represents an integer. ) is R z1 -(O) tz -L z - Unit (tz represents an integer of 0 or 1, Lz ) may be substituted with R z1 -O-(CH2CH2-O-) nz -The unit (nz represents an integer between 1 and 30) is preferable.

[0046] [ka]

[0047] (In formulas (a1) to (a3), R 2 ~R 4 R represents a saturated or unsaturated hydrocarbon group having 1 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms. 2 ~R 4 The hydrogen atoms constituting it may be substituted with ether groups. p1, q1, and r1 each represent integers between 1 and 200, and the sum of p1, q1, and r1 is between 1 and 200.

[0048] Furthermore, examples of monomers include compounds that contain two or more aromatic rings or one or more crosslinking rings in one molecule, and have one or more polymerizable double bonds (hereinafter, these may be collectively referred to as "specific cyclic compounds").

[0049] The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocycle, and is preferably an aromatic hydrocarbon ring such as a benzene ring or a naphthalene ring. Compounds containing two or more aromatic rings and one or more polymerizable double bonds in one molecule include: biphenylmethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, ethoxylated phenylphenol (meth)acrylate (total oxyethylene units are preferably 1 to 30, more preferably 2 to 20), ethoxylated cumylphenol (meth)acrylate (total oxyethylene units are preferably 1 to 30, more preferably 2 to 20), 2-(1-naphthyloxy)ethyl (meth)acrylate, 2-(2-naphthyloxy)ethyl (meth)acrylate, naphthyloxypolyethylene glycol (meth)acrylate, N-vinylcarbazole, and other compounds containing one polymerizable double bond and two or more aromatic rings in one molecule; divinylnaphthalene, propoxylated ethoxylated bisphenol Examples include compounds containing two polymerizable double bonds and two or more aromatic rings in one molecule, such as A di(meth)acrylate (total oxyethylene units preferably 2 to 30, more preferably 5 to 20; total oxypropylene units preferably 2 to 30, more preferably 5 to 20), ethoxylated bisphenol A di(meth)acrylate (total oxyethylene units preferably 2 to 40, more preferably 3 to 30), ethoxylated bisphenol F di(meth)acrylate (total oxyethylene units preferably 2 to 40, more preferably 3 to 30), propoxylated bisphenol A di(meth)acrylate (total oxypropylene units preferably 2 to 40, more preferably 3 to 30), 9,9-bis[4-(2-(meth)acryloxyethoxy)phenyl]fluorene, diallyl diphenate, and diallyl naphthalenedicarboxylic acid ester. R contained in the above compound x1 -O-(R x2 -O-) n - Unit (R x1 is phenylphenyl R represents a group, cumylphenyl group, naphthyl group, or (meth)acryloyl group. x2represents an ethylene group or a propylene group. n represents an integer. If n is 2 or greater, R x2 They may be the same or different. ) is R x1 -(O) tx -L x - Unit (tx represents an integer of 0 or 1, L x ) may be substituted with R x1 -O-(CH2CH2-O-) nx - Preferably, the unit is nx (where nx represents an integer between 1 and 30).

[0050] Examples of the aforementioned crosslinking rings include saturated or unsaturated crosslinking rings, with saturated crosslinking rings being preferred. Examples of compounds containing one or more crosslinking rings and one or more polymerizable double bonds in one molecule include compounds containing one polymerizable double bond and one crosslinking ring in one molecule, such as isobornyl (meth)acrylate; compounds containing two polymerizable double bonds and one crosslinking ring in one molecule, such as tricyclodecanedimethyl di(meth)acrylate; and compounds containing one polymerizable double bond and one crosslinking ring in one molecule are preferred.

[0051] The content of the specific cyclic compound is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and particularly preferably 99 parts by mass or more, out of 100 parts by mass of the total of the solvent and monomer, with an upper limit of 100 parts by mass.

[0052] Of the above monomers, monofunctional (meth)acrylic acid esters or crosslinkable (meth)acrylic acid esters (both collectively referred to as (meth)acrylic acid esters) are particularly preferred.

[0053] The composition of the present invention may further contain a polymer (resin). Hereinafter, a composition containing a polymer (resin) may be referred to as a resin composition. The resin composition may contain a polymer (resin) and the monomers described above. One or more types of polymers (resins) can be used, and examples include polyamides such as 6-nylon, 66-nylon, and 12-nylon; polyimides; polyurethanes; polyolefins such as polyethylene and polypropylene; polyesters such as PET, PBT, and PEN; polyvinyl chlorides; polyvinylidene chlorides; polyvinyl acetates; polystyrenes; (meth)acrylic resin polymers; ABS resins; fluororesins; phenol-formaldehyde resins; phenolic resins such as cresol-formaldehyde resins; epoxy resins; urea resins; melamine resins; amino resins such as guanamine resins; polyvinyl butyral resins; polyurethane resins; ethylene-vinyl acetate copolymer resins; ethylene-(meth)acrylic acid ester copolymer resins, and other soft and hard resins. Among those listed above, polyimides, polyurethanes, polyesters, (meth)acrylic resin polymers, phenolic resins, amino resins, and epoxy resins are more preferred.

[0054] 6. Composition The composition of the present invention comprises the above-mentioned metal oxide particles, a dispersant, and at least one of a solvent and a monomer. As described above, the amount of phosphoric acid in the dispersant is reduced, and as a result, the amount of phosphoric acid is also reduced in the composition of the present invention containing the dispersant. The amount of phosphoric acid is 0.60% by mass or less, preferably 0.5% by mass or less, more preferably 0.3% by mass or less, even more preferably 0.2% by mass or less, and even more preferably 0.1% by mass or less, with a lower limit of 0% by mass or 0.01% by mass, based on 100% by mass of the metal oxide particles. Note that if the metal oxide particles are coated with a dispersant or a surface treatment agent, the amount of coating is not included in 100% by mass of the metal oxide particles when determining the amount of phosphoric acid.

[0055] The composition of the present invention exhibits good compatibility between metal oxide particles and dispersion medium, and the total light transmittance is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more, with no particular upper limit, but for example 70%. The haze is preferably 50% or less, more preferably 40% or less, and even more preferably 35% or less.

[0056] The composition of the present invention may contain other additives such as curing agents, curing accelerators, colorants, internal release agents, coupling agents, reactive diluents, plasticizers, stabilizers, flame retardant aids, crosslinking agents, low shrinkage agents, polymerization inhibitors, antioxidants, ultraviolet absorbers, defoaming agents, leveling agents, thixotropes, and thickeners, to the extent that they do not impair the effects of the present invention. The content of these additives is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 0 to 3 parts by mass, per 100 parts by mass of the total composition.

[0057] The composition of the present invention can be prepared by mixing metal oxide particles, a dispersant, a solvent, and at least one monomer. For example, it can be prepared by coating metal oxide particles with the dispersant, preferably coating the metal oxide particles with a surface treatment agent, then further coating the metal oxide particles with the dispersant, and finally mixing the coated metal oxide particles with the solvent and at least one monomer.

[0058] The amount of dispersant used when preparing the composition of the present invention is preferably 10 parts by mass or more, more preferably 13 parts by mass or more, even more preferably 15 parts by mass or more, and even more preferably 18 parts by mass or more, per 100 parts by mass of metal oxide particles. The dispersant used in the present invention has a reduced amount of phosphoric acid, and even when an amount greater than the predetermined range described above is used, the compatibility between the metal oxide particles and the dispersion medium does not decrease, and it is also expected that the storage stability of the composition containing the metal oxide particles, dispersion medium and dispersant will be improved. There is no particular upper limit to the amount of dispersant used, but the amount used may be 30 parts by mass or less per 100 parts by mass of metal oxide particles. When using a dispersant with metal oxide particles coated with a surface treatment agent, the amount of metal oxide particles includes the amount of coating with the surface treatment agent.

[0059] Metal oxide particles coated with the above-mentioned dispersant may be produced by contacting uncoated metal oxide particles with the dispersant, or by contacting metal oxide nanoparticles coated with a carboxylic acid compound obtained by hydrothermal synthesis with the dispersant. In the above-mentioned production method via hydrothermal synthesis, for example, in the presence of water, one of the following can be subjected to a hydrothermal reaction to produce metal oxide particles a coated with a carboxylic acid compound (hydrothermal step): (i) a mixture of a compound capable of generating a metal oxide by hydrothermal reaction (hereinafter sometimes referred to as "metal oxide particle precursor" or simply "precursor") and a carboxylic acid compound, (ii) a salt of the precursor and the carboxylic acid compound, or (iii) a salt of a metal and the carboxylic acid compound. Further contact of particles a with the dispersant can produce metal oxide particles b coated with the dispersant and the carboxylic acid compound.

[0060] The metal oxide particle precursor in (i) above is preferably a compound that generates a metal oxide by a hydrothermal reaction, and specifically includes various metals and hydroxides, chlorides, oxychlorides, oxyacetates, oxynitrates, sulfates, acetates, organic acid salts, alkoxides, etc. The metal in the metal oxide particle precursor in embodiments (i) and (ii), and the metal in embodiment (iii), mean the metal that constitutes the metal oxide particles of the present invention. When subjecting any of (i) to (iii) above to a hydrothermal reaction, it is preferable to add an organic solvent such as a hydrocarbon, ketone, ether, or alcohol that shows good solubility to them.

[0061] The hydrothermal reaction is preferably carried out at a pressure of, for example, 0.1 MPaG to 2 MPaG (meaning gauge pressure). Within this pressure range, the reaction proceeds easily, and the particle size and crystal system of the metal oxide particles can be easily controlled. The temperature of the hydrothermal reaction is preferably 200°C or lower, more preferably 190°C or lower, considering the saturated vapor pressure of water. From the viewpoint of suppressing the reaction time, it is preferably 100°C or higher, more preferably 120°C or higher. The reaction time can be adjusted from the relationship between the reaction temperature, pressure, and yield, and is usually 0.1 to 50 hours, preferably 1 to 20 hours.

[0062] When contacting the metal oxide particles coated with the carboxylic acid compound obtained in the hydrothermal reaction with the dispersant, for example, the dispersant can be added to a solution obtained by mixing the metal oxide particles coated with the carboxylic acid compound with a solvent, and the mixture can be heated at 50-100°C for 1-10 hours.

[0063] 7.Cured product Among the compositions of the present invention, compositions containing monomers can be cured. The shape of the resulting cured product is not particularly limited and can be plate-like, sheet-like, film-like, or fibrous. In particular, the thickness of the cured product when it is plate-like, sheet-like, or film-like, and the diameter when it is fibrous, is preferably 1 μm to 1 mm, more preferably 5 to 500 μm. The refractive index of the cured product can be, for example, 1.750 or higher, more preferably 1.755 or higher, and even more preferably 1.760 or higher, with no particular upper limit, but for example 1.790. The haze of the cured product is preferably 50% or less, more preferably 1% or less, with no particular lower limit, but for example 0.1%. The refractive index and haze values ​​mentioned above are preferably for when the thickness or fiber diameter of the cured product is 1 μm to 1 mm (preferably 5 to 500 μm).

[0064] 8.Applications The metal oxide particles of the present invention have good dispersibility in solvents or monomers, making them suitable for various applications, such as articles molded or cured using dispersions. Applications requiring high dispersibility include, for example, resist applications, optical applications, coating applications, and adhesive applications. They are suitably used in optical lenses, adhesives for optical films, adhesives for optical films, resin compositions for nanoimprints, microlens arrays, anti-reflective layers used in transparent electrodes, anti-reflective films and anti-reflective agents, surface coatings for optical lenses, organic EL light extraction layers, various hard coating materials, planarization films for TFTs, overcoats for color filters, various protective films such as anti-reflective films, and optical materials such as optical filters, insulating films for touch sensors, insulating films for TFTs, photospacers for color filters, and protective films for touch panels. In particular, the coated metal oxide nanoparticles of the present invention have outstanding dispersibility, high refractive index, high hardness, and high stability, making them preferable for use in optical lenses, surface coatings for optical lenses, various hard coating materials, insulating films for touch sensors, insulating films for TFTs, and protective films for touch panels.

[0065] Furthermore, in addition to optical applications, the metal oxide particles of the present invention can be applied to semiconductor gate insulating films and capacitor insulating films for memory such as DRAM, taking advantage of their high dielectric constant. As a method for obtaining such high dielectric constant insulating films, a method is known in which organometallic precursors are deposited by vapor phase growth methods such as CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition), followed by oxidation treatment. Obtaining a metal oxide with the desired high dielectric constant requires high-temperature treatment of 600°C or higher, but this can lead to phenomena that cause operational instability of the semiconductor layer, including pinning. The coated metal oxide nanoparticles of the present invention do not require high-temperature treatment, already possess a high dielectric constant at the time of production, and can be laminated to accommodate semiconductor miniaturization. At the same time, because high-temperature treatment is not required, they can also be applied to semiconductor manufacturing on plastic substrates. Other applications of the zirconium oxide nanoparticles of the present invention include dental materials such as dentures, pencil leads for mechanical pencils, and pencil leads for wooden shafts. [Examples]

[0066] The present invention will be described in more detail below with reference to examples. The present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit described below, and all such modifications are included within the technical scope of the present invention.

[0067] The physical properties and characteristics disclosed in the examples and comparative examples were measured by the following methods.

[0068] (1) Analysis of the crystal structure The crystal structure of zirconium oxide particles was analyzed using an X-ray diffractometer (Rigaku Corporation, RINT-TTRIII). The measurement conditions were as follows: X-ray source: CuKα (0.154nm) X-ray output settings: 50kV, 300mA Sampling width: 0.0200° Scan speed: 10.0000° / min Measurement range: 10~75° Measurement temperature: 25℃

[0069] (2) Determination of the proportion of tetragonal and monoclinic crystals Based on values ​​calculated using an X-ray diffractometer (Rigaku Corporation, RINT-TTRIII), the values ​​were quantified using the reference intensity ratio method (RIP method) with calculation software (Rigaku Corporation, PDXL) (peak assignment was also done according to the specifications of the calculation software). In this measurement, it is difficult to distinguish between tetragonal and cubic crystals, and even if cubic crystals are present, their proportion is counted as the proportion of tetragonal crystals.

[0070] (3) Calculation of crystallite size by X-ray diffraction analysis The crystallite size of the zirconium oxide particles was calculated using calculation software (PDXL, Rigaku Corporation) based on the full width at half maximum of the 30° peak, which was analyzed and calculated using an X-ray diffractometer (RINT-TTRIII, Rigaku Corporation).

[0071] (4) Measurement of average primary particle size using an electron microscope The average primary particle diameter of coated zirconium oxide particles was measured by observation using an ultra-high-resolution field emission scanning electron microscope (Hitachi High-Technologies Corporation, S-4800). Coated zirconium oxide particles were observed at a magnification of 150,000x, and the length along the long axis of each particle was measured for any 100 particles. The average value of these measurements was defined as the average primary particle diameter.

[0072] (5) Measurement of organic content Using a TG-DTA (thermogravimetric-indicative thermal analysis) apparatus, coated zirconium oxide particles were heated from room temperature to 800°C at a rate of 10°C / min in an air atmosphere, and the weight (mass) loss rate of the particles was measured. This weight (mass) loss rate was defined as the organic content of the coated zirconium oxide particles.

[0073] (6) Carboxylic acid content A mixture of coated zirconium oxide particles and acetic acid was measured using gas chromatography, and the carboxylic acid content in the coated zirconium oxide particles was quantified using an internal standard method. The column used was Agilent J&W GC Column - DB-FFAP from Agilent Technologies, Inc.

[0074] (7) X-ray fluorescence analysis The mass ratio of Zr and P in coated zirconium oxide particles was measured using an X-ray fluorescence analyzer (ZSX Primus II, Rigaku Corporation). The P / M ratio was calculated from the obtained mass ratio using the following formula. P / M = (mass ratio of P) / (mass ratio of Zr)

[0075] (8) Dispersant coverage A dispersant containing a phosphate compound and coated zirconium oxide particles were dispersed in biacetic acid to prepare the samples for measurement, and measured using a Variann "VNMRS" (resonance frequency: 600 MHz, number of integrations: 128). If both i) and ii) below were satisfied, it was determined that all the phosphate compounds in the particles were coated on the particle surface, and the dispersant coating rate was set to 100%. i) The peak of the dispersant containing phosphate compounds is only present outside the range of -0.1 to 0.1 ppm. ii) Peaks for coated zirconium oxide particles are present only within the range of -0.1 to 0.1 ppm. In this measurement, coated zirconium oxide particles refer to zirconium oxide particles coated with both a surface treatment agent and a dispersant containing a phosphate compound.

[0076] (9) Evaluation of variance 20 mL of zirconium oxide particle dispersion was poured into a 30 mm outer diameter test tube and left upright in a 25°C atmosphere for 24 hours. If necessary, the solution was heated until the minimum fluidity required to pour the sample into the test tube was achieved. After standing, the bottom of the test tube was observed and evaluated as ○ if no precipitate was present and × if a precipitate was present.

[0077] (10) Measurement of total light transmittance The total light transmittance of the inorganic particle dispersion was measured using a turbidimeter (NDH7000, manufactured by Nippon Denshoku Industries Co., Ltd.). A quartz cell with a path length of 1 cm was used.

[0078] (11) Measurement of haze The haze of the zirconium oxide particle dispersion was measured using a turbidimeter (NDH7000, manufactured by Nippon Denshoku Industries Co., Ltd.). A quartz cell with a path length of 1 cm was used.

[0079] (12) Transparency assessment A PET film with a thickness of 100 microns (product name: Cosmoshine AS4300, manufactured by Toyobo Co., Ltd.) was coated with the composition described later using a bar coater #20, dried at 80°C for 5 minutes, and then subjected to a high-pressure mercury lamp treatment of 1000 mJ / cm². 2 The material was cured by irradiation with ultraviolet light to obtain a cured product (dry film thickness: 5 microns). The haze in the thickness direction of the prepared cured product was measured using a turbidimeter (NDH7000, manufactured by Nippon Denshoku Industries Co., Ltd.) and evaluated as follows. 〇: 1% or less, △: 1%~50%, ×: over 50%

[0080] Manufacturing Example 1: Production of coated zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid (coated ZrO2 particles 1) 782 g of zirconium 2-ethylhexanoate mineral spirit solution (44% by mass zirconium 2-ethylhexanoate, manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was mixed with pure water (268 g). The resulting mixture was placed in an autoclave equipped with a stirrer, and the atmosphere inside the autoclave was replaced with nitrogen gas. The mixture was then heated to 180°C and held at this temperature for 16 hours (autoclave pressure of 0.94 MPa) to react and produce zirconium oxide particles. Subsequently, the mixture was removed after the reaction, the precipitate accumulated at the bottom was filtered off and washed with acetone, and then dried. When the dried precipitate (100 g) was dispersed in toluene (800 mL), a cloudy solution was obtained. Next, as a purification step, the solution was filtered again using quantitative filter paper (Advantec Toyo Co., Ltd., No. 5C) to remove coarse particles from the precipitate. Furthermore, white zirconium oxide nanoparticles (coated ZrO2 particles 1) were recovered by concentrating the filtrate under reduced pressure to remove toluene. Upon examining the crystal structure of the obtained coated ZrO2 particles 1, diffraction lines attributed to tetragonal and monoclinic crystals were detected. Based on the intensity of the diffraction lines, the ratio of tetragonal to monoclinic crystals was 54 / 46, and the particle size (crystallite size) was 5 nm. The average particle size (average primary particle size based on the number of particles) of coated ZrO2 particles 1, as measured by electron microscopy, was 12 nm. Furthermore, analysis of the obtained coated ZrO2 particles 1 by infrared absorption spectroscopy revealed absorption originating from CH and absorption originating from COOH. These absorptions are thought to be due to 2-ethylhexanoic acid and / or carboxylates derived from 2-ethylhexanoic acid coating the coated ZrO2 particles 1. Furthermore, the organic content of coated ZrO2 particles 1, measured according to "(5) Measurement of Organic Content" described above, was 12% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coating coated ZrO2 particles 1 constituted 12% by mass of the entire coated ZrO2 particles 1.

[0081] Manufacturing Example 2: Production of zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and polyethylene glycol monomethyl ether phosphate (coated ZrO2 particles 2A) The coated ZrO2 particles 1 (40g) obtained in the above Production Example 1 were mixed with toluene (40g) and uniformly stirred to obtain a transparent dispersion solution. 8.8g of dispersant A, having the composition shown in formula (p1) and Table 1, was added to this solution and mixed at 80°C for 3 hours to obtain a zirconium oxide dispersion. Next, n-hexane was added to agglomerate the dispersed particles and obtain a turbid liquid. After separating the agglomerated particles from the turbid liquid using filter paper, the mixture was heated and dried at room temperature to prepare zirconium oxide nanoparticles (coated ZrO2 particles 2A) coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid and polyethylene glycol monomethyl ether phosphate. The organic content of coated ZrO2 particles 2A, measured according to "(5) Measurement of Organic Content," was 13% by mass. The 2-ethylhexanoic acid content of coated ZrO2 particles 2A, measured according to "(6) Carboxylic Acid Content," was 1% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate ester (including phosphoric acid) constituted 1% by mass and 12% by mass, respectively, of the total coated ZrO2 particles 2A (100% by mass). The P / M ratio (where M is Zr), measured according to "(7) X-ray Fluorescence Analysis," was 3.9 / 94 = 0.041. The dispersant coating rate of coated ZrO2 particles 2A, measured according to "(8) Dispersant Coating Rate," was 100%.

[0082] Manufacturing Example 3 Coated ZrO2 particles 2B were prepared in the same manner as in Production Example 2, except that dispersant B was used instead of dispersant A. The organic content of coated ZrO2 particles 2B, measured according to "(5) Measurement of Organic Content," was 13% by mass. The 2-ethylhexanoic acid content of coated ZrO2 particles 2B, measured according to "(6) Carboxylic Acid Content," was 1% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate ester (including phosphoric acid) constituted 1% by mass and 12% by mass, respectively, of the total coated ZrO2 particles 2B (100% by mass). The P / M ratio (where M is Zr), measured according to "(7) X-ray Fluorescence Analysis," was 3.7 / 94 = 0.039. The dispersant coating rate of coated ZrO2 particles 2B, measured according to "(8) Dispersant Coating Rate," was 100%.

[0083] Manufacturing Example 4 Coated ZrO2 particles 2C were prepared in the same manner as in Production Example 2, except that dispersant C was used instead of dispersant A. The organic content of coated ZrO2 particles 2C, measured according to "(5) Measurement of Organic Content," was 21% by mass. Furthermore, the 2-ethylhexanoic acid content of coated ZrO2 particles 2C, measured according to "(6) Carboxylic Acid Content," was 2% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate (including phosphoric acid) constituted 2% by mass and 19% by mass, respectively, of the total coated ZrO2 particles 2C (100% by mass). The P / M ratio (where M is Zr) measured according to "(7) X-ray fluorescence analysis" was 2.6 / 95 = 0.027. The dispersant coating rate of coated ZrO2 particles 2C measured according to "(8) Dispersant coating rate" was 100%.

[0084] Manufacturing Example 5 Coated ZrO2 particles 2D were prepared in the same manner as in Production Example 2, except that dispersant D was used instead of dispersant A. The organic content of coated ZrO2 particles 2D, measured according to "(5) Measurement of Organic Content," was 23% by mass. The 2-ethylhexanoic acid content of coated ZrO2 particles 2D, measured according to "(6) Carboxylic Acid Content," was 2% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate (including phosphoric acid) constituted 2% by mass and 21% by mass, respectively, of the total ZrO2 particles 2D (100% by mass). The P / M ratio (where M is Zr), measured according to "(7) X-ray Fluorescence Analysis," was 2.3 / 96 = 0.024. The dispersant coating rate of coated ZrO2 particles 2D, measured according to "(8) Dispersant Coating Rate," was 100%.

[0085] Manufacturing Example 6 Coated ZrO2 particles 2E were prepared in the same manner as in Production Example 2, except that dispersant E was used instead of dispersant A. The organic content of coated ZrO2 particles 2E, measured according to "(5) Measurement of Organic Content," was 13% by mass. The 2-ethylhexanoic acid content of coated ZrO2 particles 2E, measured according to "(6) Carboxylic Acid Content," was 1% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate ester (including phosphoric acid) constituted 1% by mass and 12% by mass, respectively, of the total coated ZrO2 particles 2E (100% by mass). The P / M ratio (M is Zr), measured according to "(7) X-ray Fluorescence Analysis," was 4.6 / 93 = 0.049. The dispersant coating rate of coated ZrO2 particles 2E, measured according to "(8) Dispersant Coating Rate," was 100%.

[0086] Manufacturing example 7 Coated ZrO2 particles 2F were prepared in the same manner as in Production Example 2, except that dispersant F was used instead of dispersant A. The organic content of coated ZrO2 particles 2F, measured according to "(5) Measurement of Organic Content," was 13% by mass. The 2-ethylhexanoic acid content of coated ZrO2 particles 2F, measured according to "(6) Carboxylic Acid Content," was 1% by mass. As a result, it was found that 2-ethylhexanoic acid and ethylene glycol monomethyl ether phosphate ester (including phosphoric acid) constituted 1% by mass and 12% by mass, respectively, of the total coated ZrO2 particles 2F (100% by mass). The P / M ratio (where M is Zr), measured according to "(7) X-ray Fluorescence Analysis," was 3.3 / 95 = 0.035. The dispersant coating rate of coated ZrO2 particles 2F, measured according to "(8) Dispersant Coating Rate," was 100%.

[0087] Manufacturing Example 8: Production of zirconium oxide nanoparticles coated with 2-ethylhexanoic acid, ethylene glycol monomethyl ether phosphate, acid anhydride, and its hydrolysate (coated ZrO2 particles 2G) The coated ZrO2 particles 1 (40 g) obtained in Production Example 1 above were mixed with toluene (40 g) and uniformly stirred to obtain a transparent dispersion solution. Dispersant A (ethylene glycol monomethyl ether phosphate, 7.0 g) and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid anhydride (1.1 g) were added to this solution as surface treatment agents, and the mixture was heated at 80°C for 3 hours to obtain a zirconium oxide dispersion. Next, n-hexane was added to agglomerate the dispersed particles and obtain a turbid liquid. After separating the agglomerated particles from the turbid liquid using filter paper, the mixture was heated and dried at room temperature to prepare zirconium oxide nanoparticles (coated ZrO2 particles 2G) coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid, ethylene glycol monomethyl ether phosphate ester, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid anhydride and its hydrolysate. The organic content of 2G of coated ZrO2 particles, measured according to "(5) Measurement of Organic Content," was 13% by mass. The 2-ethylhexanoic acid content of 2G of coated ZrO2 particles, measured according to "(6) Carboxylic Acid Content," was 1% by mass. As a result, it was found that, relative to the total (100% by mass) of 2G of coated ZrO2 particles, 2-ethylhexanoic acid was 1% by mass, and ethylene glycol monomethyl ether phosphate ester (including phosphoric acid content), acid anhydrides, and their hydrolysates accounted for 12% by mass. The P / M (M is Zr) measured according to "(7) X-ray Fluorescence Analysis" was 3.1 / 94 = 0.033. The dispersant coating rate of 2G of coated ZrO2 particles, measured according to "(8) Dispersant Coating Rate," was 100%.

[0088] The dispersants A to F used in the above-described manufacturing example are compositions containing polyethylene glycol monomethyl ether phosphate ester represented by the following formula (p1), where R 1 , R 2 The values ​​of n, the proportion of monoesters with a=1, the proportion of diesters with a=2, and the phosphoric acid content are shown in Table 1 below. Note that the proportions of monoesters and diesters are molar ratios when their total is set to 100%, and the phosphoric acid content is the value when the total of monoesters, diesters, and phosphoric acid is set to 100% by mass.

[0089] [ka]

[0090] [Table 1]

[0091] Example 1-1 By mixing coated ZrO2 particles 2A (20 g) obtained in Production Example 2 with methanol (8.5 g) and uniformly stirring, a methanol dispersion with a zirconium oxide particle content of 70% was obtained.

[0092] Examples 1-2 Coated ZrO2 particles 2B (20 g) obtained in Production Example 3 and propylene glycol monomethyl ether (hereinafter referred to as PGM) (8.5 g) were mixed and uniformly stirred to obtain a PGM dispersion with a zirconium oxide particle content of 70%.

[0093] Examples 1-3 Coated ZrO2 particles 2C (20 g) obtained in Production Example 4 and methyl ethyl ketone (hereinafter referred to as MEK) (8.5 g) were mixed and uniformly stirred to obtain a MEK dispersion with a zirconium oxide particle content of 70%.

[0094] Examples 1-4 Coated ZrO2 particles 2D (20 g) obtained in Production Example 5 and propylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA) (8.5 g) were mixed and uniformly stirred to obtain a PGMEA dispersion with a zirconium oxide particle content of 70%.

[0095] Examples 1-5 2G (20g) of coated ZrO2 particles obtained in Production Example 8 and 5.0g of m-phenoxybenzyl acrylate (hereafter, PBZA) were mixed and uniformly stirred to obtain a PBZA dispersion with a zirconium oxide particle content of 80%.

[0096] Comparative Example 1-1 By mixing coated ZrO2 particles 2E (20 g) obtained in Production Example 6 with methanol (8.5 g) and uniformly stirring, a methanol dispersion with a zirconium oxide particle content of 70% was obtained.

[0097] Comparative Example 1-2 By blending the coated ZrO2 particles 2F (20 g) and PGM (8.5 g) obtained in Production Example 7 and uniformly stirring, a PGM dispersion with a zirconium oxide particle content of 70% was obtained.

[0098] Table 2 shows the results of measurements taken for Examples 1-1 to 1-5 above, according to the above-mentioned "(5) Measurement of organic content", "(7) X-ray fluorescence analysis", "(9) Evaluation of dispersibility", "(10) Measurement of total light transmittance", and "(11) Measurement of haze".

[0099] [Table 2]

[0100] Table 2 shows that in Examples 1-1 to 1-5, which used dispersants A to D with low phosphoric acid content, good dispersibility, total light transmittance, and haze were achieved because the phosphoric acid content in the composition was reduced. The amount of phosphoric acid per 100% by mass of metal oxide particles was calculated based on the amount of phosphoric acid in the dispersant used: Example 1-1: 0.10% by mass, Example 1-2: 0.08% by mass, Example 1-3: 0.25% by mass, Example 1-4: 0.23% by mass, Example 1-5: 0.10% by mass, Comparative Example 1-1: 0.62% by mass, and Comparative Example 1-2: 0.75% by mass.

[0101] Examples 2-1 to 2-4 In a brownish glass bottle, 5.0 g of the dispersions obtained in Examples 1-1 to 1-4, 3.5 g of the monomers listed in Table 3 below, 9.0 g of MEK, and 0.1 g of Irgacure 184 (photoradical polymerization initiator, manufactured by BASF) were charged and stirred until homogeneous to obtain a zirconium oxide particle-containing composition. The results of the transparency evaluation (12) of the obtained zirconium oxide particle-containing composition are shown in Table 3 below. The monomers used are as follows. 3PO-TMPTA: Propoxylated (3) Trimethylolpropane Triacrylate (Product Name: SR492, manufactured by Sartomer) DPHA: Dipentaerythritol hexaacrylate (Trade name: KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.) PETA: Pentaerythritol triacrylate (Product name: SR444 NS, manufactured by Sartomer)

[0102] [Table 3]

[0103] Furthermore, Table 3 shows that the cured products obtained from the monomer compositions prepared using Examples 1-1 to 1-4 exhibit good transparency and good compatibility between the metal oxide particles and the monomers.

[0104] Examples 3-1 to 3-2 In Examples 1-1 and 1-2, 5.0 g of the dispersion was placed in a brownish glass bottle with 0.87 g of PETA and 0.03 g of Irgacure 184 (photoradical polymerization initiator, manufactured by BASF), and the mixture was stirred until homogeneous to obtain a zirconium oxide particle-containing composition. The obtained dispersion was then subjected to a rotary evaporator to remove the dispersion medium (organic solvent) under reduced pressure to obtain a zirconium oxide particle monomer dispersion. The obtained dispersion was coated onto a 100 micron thick PET film (product name: Cosmoshine AS4300, manufactured by Toyobo Co., Ltd.) using applicator #01, and heated with a high-pressure mercury lamp at 1000 mJ / cm². 2 The material was cured by irradiation with ultraviolet light to obtain a cured product (dry film thickness: 100 microns). The prepared cured product was cut to a size of 35 mm in length and 8 mm in width. A small amount of intermediate solution (sulfur-iodide methylene solution) was dropped into the measuring section of an ATAGO DR-M4 multi-wavelength Abbe refractometer (measurement temperature 20°C, interference filter wavelength 589 (D) nm), and the cut cured product was placed on top with the coated side down to prevent air bubbles from entering, and the refractive index was measured.

[0105] Example 3-3 For the dispersions obtained in Examples 1-5, 5.0 g of the solution was placed in a brownish glass bottle with 0.03 g of Irgacure 184 (photoradical polymerization initiator, manufactured by BASF), and the mixture was stirred until homogeneous to obtain a zirconium oxide particle monomer dispersion. The obtained dispersion was coated onto a 100 micron thick PET film (product name: Cosmoshine AS4300, manufactured by Toyobo Co., Ltd.) using applicator #01, and heated with a high-pressure mercury lamp at 1000 mJ / cm². 2The material was cured by irradiation with ultraviolet light to obtain a cured product (dry film thickness: 100 microns). The prepared cured product was cut to a size of 35 mm in length and 8 mm in width. A small amount of intermediate solution (sulfur-iodide methylene solution) was dropped into the measuring section of an ATAGO DR-M4 multi-wavelength Abbe refractometer (measurement temperature 20°C, interference filter wavelength 589 (D) nm), and the cut cured product was placed on top with the coated side down to prevent air bubbles from entering, and the refractive index was measured.

[0106] The results are shown in Table 4 below.

[0107] [Table 4]

[0108] Furthermore, as can be seen from Table 4, in the monomer compositions prepared using Examples 1-1 to 1-2 and 1-5, the compatibility between zirconium oxide particles and monomers is good, allowing for a sufficiently high content of zirconium oxide particles, and as a result, the refractive index of the cured monomer composition can be increased.

Claims

1. Metal oxide particles with an average primary particle diameter of 50 nm or less, A dispersant containing a phosphate compound, A composition comprising (meth)acrylic acid ester, The composition may contain phosphoric acid, and the amount of phosphoric acid is 0.60% by mass or less with respect to 100% by mass of metal oxide particles. The composition is characterized in that the phosphate compound is at least one of a phosphate ester or a salt thereof represented by the following formula (p1). 【Chemistry 1】 In the above formula (p1), R 1 R is a linear or branched alkyl group having 1 to 5 carbon atoms. 2 is a linear or branched alkylene group having 2 to 4 carbon atoms, where n is 1 to 10 and a is 1 to 3.

2. The composition according to claim 1, wherein the metal oxide particles are coated with the dispersant.

3. The composition according to claim 1, wherein the phosphate compound comprises a phosphate monoester in which a is 1 in the above formula (p1) and a phosphate diester in which a is 2 in the above formula (p1).

4. The composition according to any one of claims 1 to 3, wherein the ratio (P / M) of the mass of phosphorus atoms on the surface of the metal oxide particles to the mass of metal atoms (M) of the metal oxide particles is 0.001 to 0.

1.

5. The composition according to any one of claims 1 to 4, wherein the amount of the phosphoric acid compound is 5% by mass or more with respect to 100% by mass of the metal oxide particles.

6. A cured product of the composition according to any one of claims 1 to 5.

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