Method for producing zirconium oxide powder, and zirconium oxide powder

Abstract

The present invention provides a method for producing a zirconium oxide powder excellent in dispersibility in an organic solvent or a resin. The present invention is a method for producing a zirconium oxide powder, the production method being characterized by comprising: a first step for preparing a dispersion by mixing feedstocks including zirconium oxide, a phosphate represented by general formula (1) (in formula (1), R1 represents an alkyl group having 1-6 carbon atoms, M represents a hydrogen atom, a metal atom, or an organic base, n is a number from 1 to 8, and k is 1 or 2), and a solvent; and a second step for spray-drying the dispersion obtained in the first step.

Description

Method for producing zirconium oxide powder, and zirconium oxide powder

[0001] The present invention relates to a method for producing zirconium oxide powder and zirconium oxide powder, and more particularly to a method for producing zirconium oxide powder that can be easily dispersed in organic solvents and resins, and zirconium oxide powder.

[0002] Zirconium oxide has high transparency and refractive index, and is therefore primarily used as a material for increasing the refractive index in optical applications (see Patent Documents 1 to 3). When zirconium oxide is used to increase the refractive index of a resin molded body (coating film), it is required that the zirconium oxide has good dispersibility in the resin. In a conventional technique, from the standpoint of compatibility, an organic solvent dispersion of zirconium oxide is prepared, mixed with the resin, and then the organic solvent is removed to disperse the zirconium oxide in the resin (see Patent Document 4).

[0003] JP 2010-132494 A JP 2019-038738 A JP 2022-143972 A International Publication No. 2022 / 181302

[0004] As described above, when zirconium oxide is dispersed in a resin, a method is used in which a zirconium oxide organic solvent dispersion is mixed with the resin and the solvent is removed. However, this method requires a solvent removal step, which is cumbersome. Furthermore, when increasing the zirconium oxide concentration in the resin, a larger amount of dispersion is added to the resin, which requires removing and concentrating a larger amount of solvent, which increases the burden. Furthermore, with regard to the zirconium oxide dispersion itself, various issues arise, such as the need for solvent substitution to prepare a dispersion of the required solvent depending on the type of solvent, the difficulty of adjusting the zirconium oxide concentration through solvent substitution, the discharge of large amounts of organic waste liquid for preparation, and the need to comply with laws and regulations regarding hazardous materials. If the zirconium oxide powder itself had excellent dispersibility in organic solvents and resins, it would be unnecessary to remove the solvent when dispersing it in the resin or to perform solvent substitution when preparing a dispersion in an organic solvent. Therefore, there is a demand for such zirconium oxide powder with excellent dispersibility in organic solvents and resins.

[0005] In view of the above-mentioned current situation, an object of the present invention is to provide a method for producing zirconium oxide powder that has excellent dispersibility in organic solvents and resins.

[0006] The present inventors have investigated methods for producing zirconium oxide powder that has excellent dispersibility in organic solvents and resins, and have found that if a dispersion is prepared by mixing zirconium oxide with a phosphate ester of a predetermined structure and a solvent, and then the resulting dispersion is spray-dried, the resulting zirconium oxide powder has excellent dispersibility in organic solvents and resins, which led to the completion of the present invention.

[0007] That is, the present invention is as follows: [1] A method for manufacturing a compound having zirconium oxide and a compound represented by the following general formula (1):

[0008]

[0009] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. A method for producing a zirconium oxide powder, comprising: a first step of mixing raw materials containing a phosphate ester represented by the formula (I) above and a solvent to prepare a dispersion; and a second step of spray-drying the dispersion obtained in the first step.

[0010] [2] Zirconium oxide and the following general formula (1);

[0011]

[0012] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. A method for producing a resin composition, comprising: a first step of mixing raw materials containing a phosphate ester represented by the formula (I) and a solvent to prepare a dispersion; a second step of spray-drying the dispersion obtained in the first step to obtain zirconium oxide powder; and a third step of mixing a composition material containing the zirconium oxide powder obtained in the second step and a resin.

[0013] [3] The following general formula (1):

[0014]

[0015] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. ３ A zirconium oxide powder characterized by the following:

[0016] The method for producing zirconium oxide powder of the present invention is a useful method for producing zirconium oxide powder that has excellent dispersibility in organic solvents and resins and is suitable as a component for increasing the refractive index of resins.

[0017] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope that does not change the gist of the present invention.

[0018] 1. Method for producing zirconium oxide powder The present invention relates to a method for producing zirconium oxide powder by mixing zirconium oxide with a compound represented by the following general formula (1):

[0019]

[0020] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. This method for producing zirconium oxide powder includes: a first step of mixing raw materials including a phosphate ester represented by the formula (I) and a solvent to prepare a dispersion; and a second step of spray-drying the dispersion obtained in the first step. By producing zirconium oxide powder using this production method, it is possible to obtain zirconium oxide powder that has excellent dispersibility in organic solvents and resins.

[0021] The amount of phosphate ester used in the first step of the method for producing zirconium oxide powder of the present invention is preferably 5 to 40 wt% relative to 100 wt% of zirconium oxide. By using the phosphate ester in such a ratio, the zirconium oxide powder has a higher affinity for resin, and when mixed into a resin, it exhibits superior dispersibility. The amount is more preferably 7 to 35 wt%, and even more preferably 10 to 30 wt%, relative to 100 wt% of zirconium oxide.

[0022] The amount of solvent used in the first step of the method for producing zirconium oxide powder of the present invention is preferably 1 to 3000 wt% relative to 100 wt% of zirconium oxide. Using the solvent in such a ratio increases the affinity of the zirconium oxide powder to resins, resulting in superior dispersibility when mixed into resins. More preferably, the amount is 50 to 2500 wt%, and even more preferably 100 to 2000 wt% relative to 100 wt% of zirconium oxide.

[0023] The solvent used in the first step is not particularly limited, and examples thereof include water; alcohols such as methanol, ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, ethyl carbitol, butyl carbitol, 2-ethyl-1,3-hexanediol, methyl methoxybutanol, α-terpineol, β-terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, and glycerin; acetone, methyl ethyl Ketone solvents such as ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) or diisobutyl ketone (2,6-dimethyl-4-heptanone); ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether Ester-based solvents such as acetate, propylene glycol monomethyl ether acetate, ethyl diglycol acetate, and 1,2-diacetoxyethane; ether-based solvents such as tetrahydrofuran, dimethyl ether, diethyl ether, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis(2-diethoxy)ethane, and 1,2-bis(2-methoxyethoxy)ethane;Examples of suitable solvents include ester ethers such as 2-(2-butoxyethoxy)ethane acetate; ether alcohol solvents such as 2-(2-methoxyethoxy)ethanol; hydrocarbon solvents such as benzene, toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene, and light oil; nitrile solvents such as acetonitrile and propionitrile; nitrogen-containing polar solvents such as dimethylacetamide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone; and silicone oil solvents. Among these, water, methanol, and ethyl alcohol are preferred, and water is more preferred. One or more of these can be used. Note that, since some solvents pose a risk of fire or explosion, production facilities must be fireproof and explosion-proof, and sufficient safety measures must be taken during production.

[0024] The raw material used in the first step may contain other components in addition to zirconium oxide, phosphate ester, and solvent, such as higher fatty acids, higher fatty acid metal salts (metal soaps), anionic surfactants, and coupling agents such as silane coupling agents, titanium coupling agents, and aluminum coupling agents.

[0025] The silane coupling agent is not particularly limited, but may be a compound represented by the following general formula (2): ２ ｍ -Si-X ４－ｍ (2) (In formula (2), R ２ represents a non-reactive group or a group containing a reactive functional group, X represents a hydrolyzable group or a hydroxy group, and m is 1, 2, or 3.

[0026] R in the above general formula (2) ２Examples of the non-reactive group include an alkyl group, a cycloalkyl group, a halogenated alkyl group, a phenyl group, and an alkylphenyl group. Examples of the group containing a reactive functional group include a group containing an amino group, an epoxy group, a vinyl group, a mercapto group, and a (meth)acryloyl group. Therefore, specific examples of so-called non-reactive silane coupling agents having a non-reactive group include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, and dimethylmethoxyhydroxysilane.

[0027] In addition, among the silane coupling agents represented by the general formula (2), R ２is a group containing a reactive functional group, specific examples of so-called reactive silane coupling agents include, for example, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxyethyltriethoxysilane, Examples of the silane coupling agents include glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-(β-glycidoxyethoxy)propyltrimethoxysilane, γ-(meth)acryloyloxymethyltrimethoxysilane, γ-(meth)acryloyloxymethyltriethoxysilane, γ-(meth)acryloyloxyethyltrimethoxysilane, γ-(meth)acryloyloxyethyltriethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. One or more of these silane coupling agents can be used.

[0028] When the raw material used in the first step contains a silane coupling agent, the amount of silane coupling agent used is preferably 0.01 to 20 wt% relative to 100 wt% of zirconium oxide. By using the silane coupling agent in such a ratio, the zirconium oxide powder has a higher affinity for resin, and when mixed into a resin, the zirconium oxide powder has better dispersibility. The amount is more preferably 0.1 to 15 wt%, and even more preferably 0.5 to 10 wt%, relative to 100 wt% of zirconium oxide.

[0029] When a silane coupling agent is used as a raw material in the first step, the order of adding the phosphate ester and the silane coupling agent to the zirconium oxide is not particularly limited, and either may be added first.

[0030] The second step of the method for producing a zirconium oxide powder of the present invention is a step of spray-drying the dispersion obtained in the first step. In this specification, the temperature when spray-drying the dispersion refers to the inlet temperature at which the dispersion is introduced into a spray dryer, and is preferably 110 to 240°C. Drying at such a temperature increases the affinity of the zirconium oxide powder for resins, resulting in superior dispersibility when mixed into a resin. The temperature when spray-drying is more preferably 120 to 230°C, and even more preferably 130 to 200°C.

[0031] The method for producing zirconium oxide powder of the present invention may include other steps in addition to the first and second steps. Examples of other steps include a crushing step and a classification step.

[0032] 2. Method for Producing Resin Composition The present invention also relates to a method for producing a resin composition, which includes performing the first and second steps of the method for producing zirconium oxide powder described above, and then a third step of mixing a composition material containing the zirconium oxide powder obtained in the second step and a resin. Because the zirconium oxide powder obtained by the method for producing zirconium oxide powder described above has high dispersibility in resin, producing a resin composition using this method makes it possible to obtain a resin composition with high light transmittance and a high refractive index.

[0033] The amount of zirconium oxide powder used in the third step is preferably 30 to 1000% by weight, more preferably 40 to 700% by weight, even more preferably 50 to 500% by weight, and particularly preferably 50 to 350% by weight, relative to 100% by weight of the resin used in the third step.

[0034] The resin used in the third step is not particularly limited, and may be a thermoplastic resin or a thermosetting resin, for example, an epoxy resin; a phenolic resin; a polyphenylene sulfide (PPS) resin; a polyester resin; a polyamide or polyimide polymer such as polyamide or polyimide; a polyolefin resin such as polystyrene, polyethylene, or polypropylene; a chlorine-based resin such as polyvinyl chloride or polyvinylidene chloride; a fluororesin; a monofunctional (meth)acrylate such as polymethyl methacrylate, ethylene-ethyl acrylate copolymer (EEA) resin, 2-ethylhexyl (meth)acrylate, or benzyl (meth)acrylate. Examples of suitable (meth)acrylic resins include bifunctional (meth)acrylates such as ethylene glycol di(meth)acrylate and 1,6-hexanediol di(meth)acrylate, and polyfunctional (meth)acrylates such as pentaerythritol (tri / tetra)(meth)acrylate and dipentaerythritol hexa(meth)acrylate; carbonate resins such as polycarbonate; polyurethane; polyacetal; ether resins such as polyphenylene ether and polyetherimide; diene polymers such as acrylonitrile-butadiene-styrene copolymer (ABS) resin; liquid crystal resins (LCP); and silicone resins. Among these, acrylic resins are preferred, and one or more of these can be used.

[0035] The composition material containing zirconium oxide powder and resin used in the third step may contain a solvent. When a solvent is contained, the content of the solvent is preferably 1 to 300 wt % relative to 100 wt % of the composition material. More preferably, it is 10 to 200 wt %, and even more preferably, it is 30 to 100 wt %. The solvent used in the third step may be the same as the solvent used in the first step of the above-mentioned method for producing zirconium oxide powder of the present invention.

[0036] The composition material containing zirconium oxide powder and a resin used in the third step may contain a polymerization initiator. When a polymerization initiator is contained, the content is preferably 0.1 to 10 wt % relative to 100 wt % of the composition material. More preferably, it is 0.5 to 9 wt %, and even more preferably, it is 1 to 8 wt %. As the polymerization initiator, any of known photopolymerization initiators and thermal polymerization initiators can be used.

[0037] The composition material containing zirconium oxide powder and resin used in the third step may contain other components in addition to the zirconium oxide powder, resin, and solvent. Examples of other components include ultraviolet absorbers, antioxidants, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, antifoaming agents, leveling agents, gloss agents, antistatic agents, and conductive agents. The content of the other components can be appropriately optimized depending on the application and desired properties of the zirconium oxide-containing resin composition.

[0038] The method for producing a resin composition of the present invention may include other steps in addition to the above-mentioned steps 1 to 3. Examples of other steps include a resin molding step.

[0039] 3. Zirconium oxide powder and zirconium oxide powder-containing resin composition The zirconium oxide powder produced by the method for producing zirconium oxide powder of the present invention comprises zirconium oxide particles represented by the following general formula (1):

[0040]

[0041] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. This zirconium oxide powder is surface-treated with a phosphate ester represented by the formula (I). This zirconium oxide powder is characterized not only by its excellent dispersibility in organic solvents and resins, but also by its low bulk density. The bulk density is 1.5 g / cm ３ Such zirconium oxide powder, that is, zirconium oxide powder represented by the following general formula (1):

[0042]

[0043] (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. ３ The present invention also provides a zirconium oxide powder characterized by the following:

[0044] In the above general formula (1), R １ Although n may be an alkyl group having 1 to 6 carbon atoms, it is preferably an alkyl group having 1 to 5 carbon atoms. It is more preferably an alkyl group having 1 to 4 carbon atoms. Furthermore, in general formula (1), M, whether identical or different, represents a hydrogen atom, a metal atom, or an organic base, and examples of the organic base include an ammonium group and an organic amine group. Examples of metal atoms include, but are not limited to, metal atoms of Group 1 of the periodic table such as Li, Na, and K, and metal atoms of Group 2 of the periodic table such as Mg and Ca. M is preferably a hydrogen atom. In the above general formula (1), n ​​is a number from 1 to 8, but is preferably a number from 1 to 7. It is more preferably a number from 1 to 6.

[0045] The bulk density of the zirconium oxide powder of the present invention is 1.2 g / cm3 from the viewpoint of ease of powder disintegration during dispersion. ３ It is preferably 1.0 g / cm or less, and more preferably 1.0 g / cm ３ From the viewpoint of powder handling, the density is 0.05 g / cm ３ It is preferably 0.1 g / cm or more. More preferably, it is 0.1 g / cm ３ The bulk density of the zirconium oxide powder of the present invention is measured by the following method. <Method for measuring bulk density> Outer diameter: 18 mm, inner diameter: 15 mm, internal volume: 6.55 cm ３ The sample is poured into a glass container until it overflows, and any sample that rises above the top of the glass container is leveled off using a leveling board. The sample weight is calculated by subtracting the container weight from the measured weight, and the bulk density is calculated using the following formula. ３ ) = sample weight (g) / glass container volume (cm ３ )

[0046] The zirconium oxide powder of the present invention is preferably one obtained by surface-treating zirconium oxide with a phosphate ester represented by the general formula (1) in the proportion described in the method for producing the zirconium oxide powder of the present invention. By surface-treating zirconium oxide with a phosphate ester in such a proportion, the zirconium oxide powder has a higher affinity for resins and exhibits better dispersibility when mixed into resins.

[0047] The zirconium oxide powder of the present invention may be surface-treated with a component other than the phosphate ester, as long as it is surface-treated with the phosphate ester represented by the general formula (1). Examples of surface-treatment components other than the phosphate ester include silane coupling agents. Examples of silane coupling agents include those described in the method for producing the zirconium oxide powder of the present invention. Furthermore, when the zirconium oxide powder of the present invention is obtained by surface-treating the zirconium oxide powder with a silane coupling agent in addition to the phosphate ester, the amount of silane coupling agent used is as described in the method for producing the zirconium oxide powder of the present invention.

[0048] The zirconium oxide powder of the present invention and the zirconium oxide used as a raw material therefor preferably have an average particle size of 1 to 15 nm. With such an average particle size, it is possible to obtain a zirconium oxide powder with excellent dispersibility. The average particle size of the zirconium oxide powder is more preferably 1 to 12 nm, and even more preferably 1 to 10 nm. The average particle size of the zirconium oxide powder of the present invention and the zirconium oxide used as a raw material therefor can be measured by dynamic light scattering.

[0049] As described above, the zirconium oxide powder of the present invention has excellent dispersibility in resins, and can therefore be suitably used as a component for increasing the refractive index of resins. A zirconium oxide-containing resin composition containing such zirconium oxide powder of the present invention and a resin also constitutes one aspect of the present invention. Examples of resins contained in the zirconium oxide-containing resin composition of the present invention include those described in the method for producing a zirconium oxide-containing resin composition of the present invention above. The content of the zirconium oxide powder in the zirconium oxide-containing resin composition is the same as the content described in the method for producing a zirconium oxide-containing resin composition of the present invention above.

[0050] The zirconium oxide-containing resin composition may contain a solvent. The solvent contained in the resin composition is not particularly limited, and examples thereof include the same solvents as those used in the first step of the method for producing a zirconium oxide powder of the present invention. The content ratio of the solvent in the zirconium oxide-containing resin composition is the same as the amount of solvent used relative to the composition material containing the zirconium oxide powder and the resin in the third step of the method for producing a resin composition of the present invention.

[0051] The zirconium oxide-containing resin composition may contain a polymerization initiator. The polymerization initiator contained in the resin composition is not particularly limited, and one or more of known photopolymerization initiators and thermal polymerization initiators can be used. The content ratio of the polymerization initiator in the zirconium oxide-containing resin composition is the same as the content of the polymerization initiator relative to the composition material containing the zirconium oxide powder and the resin in the third step of the method for producing a resin composition of the present invention described above.

[0052] The zirconium oxide-containing resin composition may contain other components in addition to the resin, zirconium oxide powder, solvent, and polymerization initiator, which are the same as the other components contained in the composition material containing zirconium oxide powder and resin in the third step of the method for producing a resin composition of the present invention.

[0053] The content of the other components in the zirconium oxide-containing resin composition other than the resin, zirconium oxide powder, and solvent can be appropriately optimized depending on the application and desired properties of the zirconium oxide-containing resin composition.

[0054] Specific examples are given below to explain the present invention in detail, but the present invention is not limited to these examples. In the following, zirconium oxide, which is the raw material before surface treatment with a phosphate ester, will be referred to as "zirconium oxide," and the zirconium oxide after surface treatment will be referred to as "surface-treated zirconia."

[0055] Synthesis Example 1 (Synthesis of Phosphate Ester) After replacing the atmosphere in a 1000 mL four-neck flask with nitrogen, 436 g (2.1 mol) of triethylene glycol monobutyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) was charged, and 100 g (0.7 mol) of phosphoric anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added under a nitrogen atmosphere (molar ratio: phosphoric anhydride:triethylene glycol monobutyl ether=1:3). The mixture was heated and stirred at 85° C. for 6 hours to obtain 537 g of trioxyethylene monobutyl ether phosphate (in formula (1), the number of carbon atoms in R is 4, n=3; hereinafter, referred to as phosphate ester compound 1).

[0056] Synthesis Example 2 (Synthesis of phosphate ester) Tetraoxyethylene monomethyl ether phosphate (in formula (1), the number of carbon atoms in R is 1, and n = 4; hereinafter, referred to as phosphate ester compound 2) was obtained in the same manner as in Synthesis Example 1, except that triethylene glycol monobutyl ether was changed to tetraethylene glycol monomethyl ether.

[0057] Example 1 (Powder) A mixture of 3 g of the phosphoric acid ester compound 1 synthesized in the above Synthesis Example (20 wt % relative to 100 wt % of the zirconium oxide particles) and 150 g of pure water was added dropwise to a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide measured by dynamic light scattering method 3 nm) and 97 g of pure water, to obtain a slurry containing zirconium oxide particles and phosphoric acid ester compound 1. The obtained slurry was dried using a spray dryer (ADL-311 manufactured by Yamato Scientific Co., Ltd.) under conditions of an inlet temperature of 180°C and a liquid delivery flow rate of 6 ml / min, to obtain Powder A containing zirconia particles surface-treated with phosphoric acid ester compound 1 (surface-treated zirconia particles). The bulk density of Powder A was 0.89 g / cm ３ The results were as follows. (Resin Composition) 0.43 g of propylene glycol monomethyl ether (hereinafter also referred to as PGME) was added to 0.84 g of powder A, and then 0.16 g of pentaerythritol (tri / tetra)acrylate (manufactured by Daicel Allnex Corporation, hereinafter also referred to as PETRA) was added to prepare a surface-treated zirconia particle-containing resin composition A. (Cured Product) A photopolymerization initiator (Irgacure 184, manufactured by BASF Japan) was added in a proportion of 5 wt% relative to the resin concentration of 100 wt% of the surface-treated zirconia particle-containing resin composition A, and then the resulting mixture was applied to the surface of a glass plate as a substrate using an applicator. Thereafter, the mixture was air-dried overnight to volatilize the solvent, and the surface-treated zirconia particle-containing resin composition A was cured by irradiating it with light from a UV lamp, thereby obtaining a surface-treated zirconia particle-containing cured resin film A.

[0058] Example 2 (Powder) A mixture of 3 g of phosphate ester compound 1 synthesized in the above Synthesis Example (20 wt % relative to 100 wt % of the zirconium oxide particles) and 150 g of pure water was added dropwise to a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-GW (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide measured by dynamic light scattering method 8 nm) and 97 g of pure water to obtain a slurry containing zirconium oxide particles and phosphate ester compound 1. The obtained slurry was dried using a spray dryer (ADL-311 manufactured by Yamato Scientific Co., Ltd.) under conditions of an inlet temperature of 180°C and a liquid delivery flow rate of 6 mL / min to obtain powder B containing zirconia particles surface-treated with phosphate ester compound 1 (surface-treated zirconia particles). (Resin composition) 0.43g of MeOH was added to 0.72g of powder B, and then 0.28g of pentaerythritol (tri / tetra) acrylate (manufactured by Daicel Allnex Corporation, PETRA) was added to prepare a surface-treated zirconia particle-containing resin composition B. (Cured product) A photopolymerization initiator (manufactured by BASF Japan, Irgacure 184) was added at a ratio of 5% by weight relative to the resin concentration of 100% by weight of the surface-treated zirconia particle-containing resin composition B, and then the surface of the glass plate as the substrate was coated with an applicator. Thereafter, the solvent was evaporated overnight by air drying, and the zirconium element-containing composition was cured by irradiating with light from a UV lamp, to obtain a surface-treated zirconia particle-containing cured resin film B.

[0059] Examples 3 and 4 Powders C and D containing zirconia particles surface-treated with phosphate ester compound 1 (surface-treated zirconia particles), surface-treated zirconia particle-containing resin compositions C and D, and surface-treated zirconia particle-containing cured resin films C and D were obtained in the same manner as in Example 2, except that the amount of dispersant added was changed as shown in Table 1. The bulk density of Powder C was 0.93 g / cm ３ The bulk density of powder D was 0.89 g / cm ３ It was.

[0060] Example 5 (Powder) A mixture of 33.3 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide measured by dynamic light scattering method 3 nm) and 114.7 g of pure water was mixed with 1.0 g (10 wt % relative to 100 wt % of zirconium oxide particles) of phosphate ester compound 1 synthesized in the above Synthesis Example and 50.0 g of pure water, and 1.0 g (10 wt % relative to 100 wt % of zirconium oxide particles) of silane coupling agent (manufactured by Shin-Etsu Silicones Co., Ltd., KBM-503) was added dropwise to obtain a slurry containing zirconium oxide particles, phosphate ester, and silane coupling agent. This was dried using a spray dryer (ADL-311 manufactured by Yamato Scientific Co., Ltd.) under conditions of an inlet temperature of 180°C and a liquid flow rate of 6 ml / min, to obtain Powder E containing phosphate ester compound 1 and zirconia particles surface-treated with a silane coupling agent (surface-treated zirconia particles). The bulk density of Powder E was 0.92 g / cm ３ The result was as follows. (Resin composition) 0.43 g of MEK was added to 0.84 g of powder E, and then 0.16 g of pentaerythritol (tri / tetra)acrylate (PETRA, manufactured by Daicel Allnex Corporation) was added to prepare a surface-treated zirconia particle-containing resin composition E. (Cured product) A photopolymerization initiator (Irgacure 184, manufactured by BASF Japan) was added in a proportion of 5 wt% relative to the resin concentration of 100 wt% of the surface-treated zirconia particle-containing resin composition E, and then the resultant was applied to the surface of a glass plate as a substrate using an applicator. Thereafter, the solvent was volatilized by air drying overnight, and the surface-treated zirconia particle-containing resin composition was cured by irradiating it with light from a UV lamp, thereby obtaining a surface-treated zirconia particle-containing cured resin film E.

[0061] Example 6 (Powder) A mixture of 3 g of the phosphoric acid ester compound 2 synthesized in the above Synthesis Example (20 wt % relative to 100 wt % of the zirconium oxide particles) and 150 g of pure water was added dropwise to a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide measured by dynamic light scattering method 3 nm) and 97 g of pure water, to obtain a slurry containing zirconia particles surface-treated with the phosphoric acid ester compound 2 (surface-treated zirconia particles). The obtained slurry was dried using a spray dryer (ADL-311 manufactured by Yamato Scientific Co., Ltd.) under conditions of an inlet temperature of 180°C and a liquid delivery flow rate of 6 ml / min, to obtain Powder F containing zirconia particles surface-treated with the phosphoric acid ester compound 2 (surface-treated zirconia particles). The bulk density of Powder F was 0.92 g / cm ３ The result was as follows. (Resin composition) 0.43 g of PGME was added to 0.84 g of powder F, and then 0.16 g of pentaerythritol (tri / tetra)acrylate (PETRA, manufactured by Daicel Allnex Corporation) was added to prepare a surface-treated zirconia particle-containing resin composition F. (Cured product) A photopolymerization initiator (Irgacure 184, manufactured by BASF Japan) was added at a ratio of 5 wt% relative to the resin concentration of 100 wt% of the surface-treated zirconia particle-containing resin composition F, and then the resultant was applied to the surface of a glass plate as a substrate using an applicator. Thereafter, the solvent was volatilized by air drying overnight, and the zirconium element-containing resin composition was cured by irradiating it with light from a UV lamp, thereby obtaining a surface-treated zirconia particle-containing cured resin film F.

[0062] Comparative Example 1: To a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt%, average particle size of zirconium oxide measured by dynamic light scattering 3 nm) and 97 g of pure water, a mixture of 3 g of polyoxyethylene lauryl ether phosphate ester (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Plysurf A219B) (20 wt% relative to 100 wt% of zirconium oxide particles) and 150 g of pure water was added dropwise to obtain a slurry containing zirconium oxide particles and phosphate ester. This slurry was dried using a spray dryer (manufactured by Yamato Scientific Co., Ltd., ADL-311) at an inlet temperature of 180°C and a liquid delivery rate of 6 ml / min to obtain Powder G containing zirconia particles surface-treated with phosphate ester (surface-treated zirconia particles). When 0.36 g of PGME was added to 0.24 g of Powder G, the particles precipitated and became cloudy without dispersing. As a result, it was difficult to form the resulting mixture into a coating film.

[0063] Comparative Example 2 A mixture of 3 g (20 wt % relative to 100 wt % of zirconium oxide particles) of polyoxyalkylene alkyl ether phosphate ester (Plysurf A208F, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 150 g of pure water was added dropwise to a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide by dynamic light scattering method 3 nm) and 97 g of pure water, to obtain a slurry containing zirconia particles surface-treated with phosphate ester (surface-treated zirconia particles). This slurry was dried using a spray dryer (ADL-311, manufactured by Yamato Scientific Co., Ltd.) under conditions of an inlet temperature of 180°C and a liquid delivery flow rate of 6 ml / min, to obtain powder H containing surface-treated zirconia particles and phosphate ester. The bulk density of powder H was 1.01 g / cm ３ When 0.36 g of PGME was added to 0.24 g of Powder H, the particles did not disperse but precipitated, resulting in a cloudy white color. As a result, it was difficult to form the resulting mixture into a coating film.

[0064] Comparative Example 3 A mixture of 3 g of the phosphate ester compound 1 synthesized in the above Synthesis Example (20 wt % relative to 100 wt % of the zirconium oxide particles) and 150 g of pure water was added dropwise to a mixture of 50 g of an aqueous dispersion of zirconium oxide particles SZR-W (manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide concentration 30.2 wt %, average particle size of zirconium oxide measured by dynamic light scattering method 8 nm) and 97 g of pure water, to obtain a slurry containing zirconia particles surface-treated with the phosphate ester compound 1 (surface-treated zirconia particles). The obtained slurry was placed in an evaporating dish and allowed to dry overnight at 105°C to obtain powder I containing surface-treated zirconia particles and a phosphate ester. The bulk density of powder I was 1.68 g / cm ３ When 2.0 g of PGME was added to 0.2 g of powder I, the particles precipitated and became cloudy without dispersing. As a result, it was difficult to form the resulting mixture into a coating film.

[0065] The powders, surface-treated zirconia particle-containing resin compositions, and cured resin films containing surface-treated zirconia particles obtained in Examples 1 to 6 were evaluated as follows. The results are shown in Table 1. Table 1 also shows Comparative Examples 1 to 3, for which the following evaluations could not be performed. <Evaluation of Dispersibility of Powders Containing Surface-Treated Zirconia Particles in Solvents> The dispersibility of the obtained powders in organic solvents was evaluated as follows: ◎: Transparent and fluid; ○: Opaque but fluid; △: Viscosity increased regardless of transparency; ×: Dispersion state was non-uniform due to viscosity increase, aggregation, etc. <Appearance of Resin Compositions Containing Surface-Treated Zirconia Particles> The appearance of the resin compositions containing surface-treated zirconia particles was evaluated as follows. ◎: Transparent and fluid; ◯: Opaque but fluid; △: Viscosity increased regardless of transparency; ×: Non-uniform dispersion due to viscosity increase, aggregation, etc. <Film Thickness of Cured Resin Film Containing Surface-Treated Zirconia Particles> Using a "Linear Gauge Sensor GS-1830A" manufactured by Ono Sokki Co., Ltd., film thickness was measured at 20 arbitrarily selected points on the cured film, and the average value was calculated and used as the film thickness (μm). <Total Light Transmittance and Haze of Cured Resin Film Containing Surface-Treated Zirconia Particles> The total light transmittance and haze of the obtained cured film were measured using a haze meter (NDH4000 manufactured by Nippon Denshoku Kogyo Co., Ltd.). <Cracking and Adhesion of Cured Resin Film Containing Surface-Treated Zirconia Particles> The appearance of the obtained cured film was visually inspected and evaluated according to the following criteria. ◎: No cracks on the film surface or deterioration in adhesion (peeling from the substrate) were observed in the cured product. ○: Cracks on the film surface or deterioration in adhesion (peeling from the substrate) were observed in several places. ×: Cracks on the film surface or deterioration in adhesion (peeling from the substrate) were observed in many places, and the film was not formed.

[0066]

[0067] It was confirmed from Examples 1 to 6 and Comparative Examples 1 to 3 that the zirconium oxide powder (surface-treated zirconia particles) surface-treated with the phosphate ester of the present invention has high dispersibility in solvents. It was also confirmed that the zirconium oxide powder (surface-treated zirconia powder) of the present invention also has high dispersibility in resins, and that a resin composition obtained by mixing the zirconium oxide powder of the present invention with a resin is a resin composition that is highly transparent, has good adhesion to a substrate, and can form a good cured product with no observed surface cracks.

Claims

1. Zirconium oxide and the following general formula (1); (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. A method for producing a zirconium oxide powder, comprising: a first step of mixing raw materials containing a phosphate ester represented by the formula (I) and a solvent to prepare a dispersion; and a second step of spray-drying the dispersion obtained in the first step.

2. Zirconium oxide and the following general formula (1); (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms. M represents a hydrogen atom, a metal atom, or an organic base. n is a number from 1 to 8, and k is a number of 1 or 2. A method for producing a resin composition, comprising: a first step of mixing raw materials containing a phosphate ester represented by the formula (I) and a solvent to prepare a dispersion; a second step of spray-drying the dispersion obtained in the first step to obtain zirconium oxide powder; and a third step of mixing a composition material containing the zirconium oxide powder obtained in the second step and a resin.

3. The following general formula (1); (In formula (1), R １ represents an alkyl group having 1 to 6 carbon atoms; M represents a hydrogen atom, a metal atom, or an organic base; n is a number from 1 to 8, and k is a number of 1 or 2. ３ A zirconium oxide powder characterized by the following:

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