JP2011057532A - Transparent dispersion liquid of alkaline earth metal oxide-doped zirconia nanoparticle, and transparent composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent dispersion liquid of alkaline earth metal oxide-doped zirconia nanoparticles and a transparent composite, maintaining a high refractive index and high transparency as well as high durability. <P>SOLUTION: The transparent dispersion liquid of alkaline earth metal oxide-doped zirconia nanoparticles is prepared by dispersing alkaline earth metal oxide-doped zirconia nanoparticles in a dispersion medium, the nanoparticles prepared by incorporating an alkaline earth metal oxide containing at least one kind of element selected from a group consisting of Mg, Ca, Sr and Ba, as a solid solution into zirconia, and having a dispersion particle diameter of 1 nm or more and 20 nm or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion and a transparent composite, and more specifically, is suitably used as a filler material for a resin, suppresses coloring in the composite with the resin, and has a refractive index. Alkaline earth metal oxide doped zirconia nanoparticle transparent dispersion capable of improving mechanical properties and thermal properties as well as improving the transparency and transparency, and the alkaline earth metal oxide doped zirconia nano The present invention relates to a transparent composite that can be used as a glass substitute by compounding alkaline earth metal oxide-doped zirconia nanoparticles and a resin using a particle transparent dispersion.

  Conventionally, attempts have been made to improve the mechanical characteristics and thermal characteristics of a resin by combining a filler made of an inorganic oxide such as silica with a resin. As a method of combining the filler and the resin, a method of mixing a dispersion liquid in which inorganic oxide particles are dispersed in water or an organic solvent and a resin is generally used. By mixing by the method, an inorganic oxide particle composite plastic in which inorganic oxide particles are combined as the second phase can be produced.

  On the other hand, flat panel displays (FPD) such as liquid crystal displays (LCD), plasma displays (PDP) and electroluminescence displays (EL), light emitting devices such as light emitting diodes (LEDs) used in various illumination and laser transmitters, scanners, In various fields such as CCD and CMOS imaging devices used in digital cameras, etc., optical devices such as optical pickups, etc., in order to improve the characteristics of each device, substrate materials, lens materials, sealing materials and adhesion The material is required to have high transparency, and at the same time, it is required to improve the controllability of high refractive index, mechanical characteristics, thermal characteristics, and the like.

For example, as the inorganic oxide filler for improving the refractive index of the resin, metal oxide particles such as zirconia and titania are used as the high refractive index filler.
Since titania is a metal oxide that is transparent to visible light and has a high refractive index, the resulting composite exhibits a high refractive index when dispersed in a resin.
By the way, this titania is a substance having a function as a so-called photocatalyst that is excited by ultraviolet rays contained in light emitted from sunlight or a fluorescent lamp to generate strong oxidizing ozone and decomposes organic substances by this ozone. When dispersed in a resin, there is a big problem that the durability of the composite is remarkably deteriorated.

On the other hand, zirconia has no function as a photocatalyst, is chemically stable, and is a metal oxide having a high refractive index. Therefore, various attempts have been made to increase the refractive index of resins using this zirconia. For example, a cured film having a high refractive index and a high transparency having a thickness of several μm, which is obtained by applying a photocurable composition obtained by combining a zirconia particle having a primary particle size of 10 nm to 100 nm and a resin onto a film and curing the composition. Has been proposed (Patent Document 1).
Further, by using tetragonal zirconia particles having a dispersed particle diameter of 1 nm to 20 nm, a zirconia transparent dispersion and a transparent composite capable of improving the refractive index and mechanical properties and maintaining transparency have been proposed. (Patent Document 2).

Japanese Patent Laying-Open No. 2005-161111 JP 2007-99931 A

By the way, when evaluating the transparency of a transparent composite in which conventional metal oxide particles are dispersed in a resin, the thickness of the transparent composite is used as the optical path length, and the transmittance of visible light in this optical path length is obtained. If the thickness is larger, it becomes difficult to maintain transparency.
Since the cured film described in Patent Document 1 is a film having a thickness of several μm or less at most, it is used for a transparent composite having a high refractive index having a thickness of several μm or more required for various devices described above. Was difficult to respond.

  In the transparent composite described in Patent Document 2, nanometer-grade zirconia particles can be dispersed in a resin to obtain a transparent composite having high transparency and a high refractive index. The zirconia particles dispersed in the resin have a very large specific surface area, and the surface of the zirconia particles has high acidity and oxidization. There is a problem in that there is a possibility that a problem such as a problem may occur. Furthermore, in order to disperse the zirconia particles in the resin, it is necessary to modify the surface of the zirconia particles with a large amount of a surface modifier. However, when the surface is modified with a surface modifier, the refractive index is sufficiently improved. There was a problem that it was difficult to obtain the effect.

  The present invention has been made to solve the above-described problems, and is an alkaline earth metal oxide-doped zirconia nanoparticle capable of achieving both high refractive index, high transparency, and high durability. An object is to provide a transparent particle dispersion and a transparent composite.

  As a result of intensive studies in order to solve the above problems, the present inventors have obtained an alkaline earth metal oxide having a dispersed particle diameter of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia. If the product-doped zirconia nanoparticles are dispersed in a dispersion medium to obtain a transparent dispersion of alkaline earth metal oxide doped zirconia nanoparticles, not only high refractive index and high transparency can be maintained, but also high durability. The inventors have found that it is possible to maintain the present invention, and have completed the present invention.

  That is, the alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion of the present invention is an alkaline earth metal oxide having a dispersed particle size of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia. The doped zirconia nanoparticles are dispersed in a dispersion medium.

  The content of the alkaline earth metal oxide-doped zirconia nanoparticles is preferably 1% by mass or more and 70% by mass or less.

  In the transparent composite of the present invention, alkaline earth metal oxide-doped zirconia nanoparticles having a dispersed particle size of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia are dispersed in a resin. It is characterized by becoming.

  The content of the alkaline earth metal oxide-doped zirconia nanoparticles is preferably 1% by mass to 80% by mass.

According to the alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion of the present invention, an alkaline earth metal oxide having a dispersed particle size of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia Since the doped zirconia nanoparticles are dispersed in a dispersion medium, not only a high refractive index and high transparency can be achieved, but also durability can be improved.
Accordingly, when the alkaline earth metal oxide-doped zirconia nanoparticles are dispersed in the resin, a transparent composite having a high refractive index, excellent transparency, and excellent durability can be easily obtained.

  According to the transparent composite of the present invention, alkaline earth metal oxide-doped zirconia nanoparticles having a dispersed particle size of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia are dispersed in a resin. Therefore, the refractive index, transparency and durability can be improved.

It is a transmission electron microscope (TEM) image which shows the dispersion particle of the magnesia dope zirconia nanoparticle transparent dispersion liquid of Example 1 of this invention.

The form for implementing the alkaline-earth metal oxide dope zirconia nanoparticle transparent dispersion and transparent composite of this invention is demonstrated.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[Alkaline earth metal oxide doped zirconia nanoparticles transparent dispersion]
The alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion of the present embodiment is doped with an alkaline earth metal oxide having a dispersion particle diameter of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia. A transparent dispersion in which zirconia nanoparticles are dispersed in a dispersion medium.

The alkaline earth metal oxide-doped zirconia nanoparticles include alkaline earth containing one or more elements selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). Nanoparticles having a metal oxide (MO) dissolved in zirconia (ZrO ₂ ) having an average particle diameter of 1 nm to 20 nm, and the content of the alkaline earth metal oxide is It is 5 mol% or more and 30 mol% or less with respect to the total amount of earth metal oxide and zirconia. Examples of the alkaline earth metal oxide include magnesium oxide (magnesia: MgO), calcium oxide (calcia: CaO), strontium oxide (SrO), and barium oxide (BaO).

Zirconia includes tetragonal zirconia, cubic zirconia, and monoclinic zirconia, but in order to ensure high refractive index and high transparency, it is symmetrical with respect to the crystal axis. Tetragonal zirconia or cubic zirconia having
Tetragonal zirconia can be expected to improve the toughness value due to martensite transformation compared to monoclinic zirconia, and has high toughness and hardness, and the mechanical properties of the transparent composite obtained by dispersing in resin Suitable for improvement.

Here, the reason for dissolving the alkaline earth metal oxide in the zirconia nanoparticles will be described.
Alkaline earth metal oxide (MO) is an oxide composed of a basic metal, and its surface shows basicity. On the other hand, the surface of zirconia (ZrO ₂ ) is strongly acidic, and there are many hydroxyl groups on this surface. When this surface is surface-treated with a surface modifier such as a coupling agent, a large amount of surface modifier is required. And By the way, since the refractive index of this surface modifier is about 0.7 smaller than that of zirconia, the refractive index of the zirconia particles surface-treated with this surface modifier is greatly reduced. It becomes.

In the present embodiment, in order to reduce the strong acidity of the surface of the zirconia nanoparticles, the alkaline earth metal oxide is dissolved in the zirconia nanoparticles and a part of the dissolved alkaline earth metal oxide is added. Are exposed on the surface of the zirconia nanoparticles. Since the alkaline earth metal oxide has a refractive index of about 1.7, there is no risk of greatly reducing the refractive index of the zirconia nanoparticles.
Thereby, the strong acidity of the surface of a zirconia nanoparticle falls, and there is no possibility that the refractive index of this zirconia nanoparticle will also fall large.

The feature of the alkaline earth metal oxide-doped zirconia nanoparticles is that the average particle size is 1 nm or more and 20 nm or less, and the particle size range is very narrow and has a sharp particle size distribution. It is a secondary particle and is not in an aggregated state.
Here, the average particle diameter was set to 1 nm or more and 20 nm or less because the average particle diameter of the alkaline earth metal oxide-doped zirconia nanoparticles was limited to the above range, thereby producing a composite with a resin. In this case, the particles can be highly filled, and high transparency can be maintained, so that an optical functional composite having a high refractive index and an organic / inorganic composite having excellent heat resistance can be obtained.
If the average particle size is less than 1 nm, the packing density of the particles is reduced and cannot be highly packed. On the other hand, if the average particle size is more than 20 nm, the transparency is lowered, and the mechanical properties are also reduced. It is not preferable because the characteristics are deteriorated.

The content of the alkaline earth metal oxide in the alkaline earth metal oxide-doped zirconia nanoparticles is preferably 5 mol% or more and 30 mol% or less with respect to the total amount of the alkaline earth metal oxide and zirconia, and more preferably. Is 5 mol% or more and 25 mol% or less.
If the content of the alkaline earth metal oxide is less than 5 mol%, the acidic activity of the surface of the zirconia fine particles cannot be suppressed. On the other hand, if the content exceeds 30 mol%, a coarse alkaline earth metal that does not dissolve in the zirconia fine particles. Oxide fine particles appear and zirconia fine particles and alkaline earth metal oxide fine particles are mixed, which is not preferable.

The dispersion particle diameter of the alkaline earth metal oxide-doped zirconia nanoparticles in the transparent dispersion is preferably 1 nm or more and 20 nm or less, more preferably 3 nm or more and 15 nm or less, and further preferably 3 nm or more and 10 nm or less.
Here, the reason why the dispersion particle diameter of the alkaline earth metal oxide-doped zirconia nanoparticles is limited to the above range is that when the dispersion particle diameter is less than 1 nm, the crystallinity of the nanoparticles becomes poor, and the refractive index also decreases. Therefore, it is difficult to express the characteristic characteristics of the nanoparticles, while on the other hand, when the dispersed particle diameter exceeds 20 nm, the transparency is reduced in the state of a transparent dispersion or in the case of a transparent composite. It is because it falls.
Thus, since the alkaline earth metal oxide-doped zirconia nanoparticles are nanometer-class particles, even when the alkaline earth metal oxide-doped zirconia nanoparticles are dispersed in the resin to form a transparent composite, The light scattering is small, and the transparency of the transparent composite can be maintained.

The content of alkaline earth metal oxide-doped zirconia nanoparticles in the transparent dispersion is preferably 1% by mass to 70% by mass, more preferably 1% by mass to 50% by mass, and still more preferably 5% by mass. % To 30% by mass.
The reason why the content of the alkaline earth metal oxide-doped zirconia nanoparticles is limited to the above range is that this range allows the alkaline earth metal oxide-doped zirconia nanoparticles to take a good dispersion state. Here, if the content is less than 1% by mass, the effect as alkaline earth metal oxide-doped zirconia nanoparticles will be reduced, and if it exceeds 70% by mass, the transparent dispersion may gel. Or it will aggregate and a precipitate will arise, and since the characteristic as a dispersion liquid will lose | disappear, it is unpreferable.

The dispersion medium basically contains one or more of water, an organic solvent, a liquid resin monomer, and a liquid resin oligomer.
Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, benzyl alcohol, furfuryl alcohol, and other alcohols, ethyl acetate, butyl acetate, ethyl lactate, and propylene. Glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as γ-butyrolactone, diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), Ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, acetone, methyl ethyl ketone Ketones such as methyl isobutyl ketone, acetylacetone, cyclohexanone, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, amides such as dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, ethylene glycol, diethylene glycol, etc. Glycols, amino alcohols such as ethanolamine and diethanolamine, and oils such as liquid paraffin and silicone oil are preferably used, and one or more of these solvents can be used.

As the liquid resin monomer, acrylic or methacrylic monomers such as methyl acrylate and methyl methacrylate, and epoxy monomers are preferably used.
Moreover, as said liquid resin oligomer, a urethane acrylate oligomer, an epoxy acrylate oligomer, an acrylate oligomer, etc. are used suitably.

The transparent dispersion may contain inorganic fine particles, organic pigments, dispersants, coupling agents, dyes, and the like other than those described above as long as the characteristics are not impaired.
Examples of inorganic fine particles other than alkaline earth metal oxide doped zirconia nanoparticles include titanium oxide, cerium oxide, niobium oxide, barium titanate, tantalum oxide, zinc oxide, tin oxide, yttrium oxide, samarium oxide, and gadolinium oxide. And inorganic oxide fine particles having a relatively high refractive index; compound semiconductor fine particles such as cadmium sulfide; and fine particles comprising an organic pigment such as carbon black.
Examples of the dispersant include phosphate ester dispersants, polycarboxylic acid dispersants, and the like.

  When the dispersion medium is a dispersion medium other than water, the alkaline earth metal oxide-doped zirconia nanoparticles are maintained in the range of 1 nm or more and 20 n or less over time. The metal oxide-doped zirconia nanoparticles and the inorganic fine particles are preferably particles whose surfaces are treated with a surface treatment agent.

  Surface treatment agents include citric acid, lactic acid, malic acid, fumaric acid, maleic acid, aconitic acid, glutaric acid, adipic acid, hydroxyacrylic acid and other oxycarboxylic acids and esters thereof, oxalic acid, malonic acid, succinic acid. Fatty carboxylic acids such as acid, aliphatic carboxylic acids such as butyric acid, valeric acid, caproic acid, enanthic acid, caprolic acid, unsaturated carboxylic acids such as linolenic acid, linoleic acid, oleic acid, benzoic acid, phthalic acid, isophthalic acid Acid, terephthalic acid, gallic acid, mellitic acid, cinnamic acid and other aromatic carboxylic acids, catechol, pyrogallol and other oxyphenols, diethanolamine, triethanolamine and other amino alcohols, glycolaldehyde and other oxyaldehydes , Acetylacetone, benzoylacetone, stearoylacetate , Β-ketones such as stearoylbenzoylmethane and dibenzoylmethane and esters thereof (β-dicarbonyl compounds), glycols such as ethylene glycol, propylene glycol and hydroquinone, and amino acids such as glycine and alanine. .

In addition to the above surface treatment agents, silane coupling agents, titanium coupling agents, aluminum coupling agents, and zirconium coupling agents are also effective surface treatment agents.
Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, n-butyltriethoxysilane, and n-hexyltri. Methoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, p-styryltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3- Examples include acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, etc. .

Examples of titanium coupling agents include isopropyl isostearoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tri (dodecyl) benzenesulfonyl titanate, neopentyl (diallyl) oxy-tri (dioctyl) phosphate titanate, neopentyl (diallyl) oxy-tri And neododecanoyl titanate.
Examples of the aluminum coupling agent include acetoalkoxyaluminum diisopropylate.
Examples of the zirconium coupling agent include isopropyl dimethacrylisostearoyl zirconate.

Examples of the method for modifying the surface of the alkaline earth metal oxide-doped zirconia nanoparticles using the surface modifier include a wet method and a dry method.
The wet method is a method of modifying the surface of the alkaline earth metal oxide-doped zirconia nanoparticles by introducing and mixing the surface modifier and the alkaline earth metal oxide-doped zirconia nanoparticles in a solvent.
In the dry method, the surface modifier and the dried alkaline earth metal oxide-doped zirconia nanoparticles are put into a dry mixer such as a mixer and mixed, so that the surface of the alkaline earth metal oxide-doped zirconia nanoparticles is changed. It is a method of modification.

The mass ratio of the modified portion of the surface-modified alkaline earth metal oxide-doped zirconia nanoparticles is preferably 5% by mass or more and 100% by mass or less, more preferably 10% by mass or more and 60% by mass or less. It is.
Here, the reason why the mass ratio of the modified portion is limited to 5% by mass or more and 100% by mass or less is that, if the mass ratio of the modified portion is less than 5% by mass, the alkaline earth metal oxide-doped zirconia nanoparticle solvent or resin This is because the compatibility with the resin becomes difficult and the transparency may be lost when compounded with the resin. On the other hand, when the mass ratio of the modified portion exceeds 100% by mass, This is because the effect of the surface treatment agent on the resin properties is increased, and the refractive index and mechanical properties are lowered.

  The transparent dispersion preferably has a visible light transmittance of 90% or more, more preferably, when the optical path length is 10 mm, when the content of the alkaline earth metal oxide-doped zirconia nanoparticles is adjusted to 5% by mass. 95% or more.

[Transparent composite]
The transparent composite of this embodiment is a composite having transparency obtained by dispersing the alkaline earth metal oxide-doped zirconia nanoparticles in a resin.
The resin may be any resin that is transparent to light in a predetermined wavelength band such as visible light or near infrared, and is thermoplastic, thermosetting, light (electromagnetic wave) curing by visible light, ultraviolet light, infrared light, or the like. And curable resins such as electron beam curable by electron beam irradiation are preferably used.

  Examples of such resins include acrylates such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate, polycarbonate (PC), polystyrene (PS), polyether, polyester, polyarylate, polyacrylate, polyamide, phenol- Formaldehyde (phenolic resin), diethylene glycol bisallyl carbonate, acrylonitrile / styrene copolymer (AS resin), methyl methacrylate / styrene copolymer (MS resin), poly-4-methylpentene, norbornene polymer, polyurethane, epoxy, Examples thereof include silicone, and silicone, epoxy, and acrylate are particularly preferable.

The silicone resin is preferably composed of at least the following components (a) to (c).
(A) Organopolysiloxane in which at least two functional groups bonded to silicon atoms in one molecule are alkenyl groups (b) Whether at least two functional groups bonded to silicon atoms in one molecule are hydrogen atoms Or a linear organopolysiloxane (c) hydrosilylation catalyst in which both ends of the molecular chain are blocked with hydrogen atoms

(A) As an alkenyl group in a component, a vinyl group, an allyl group, a pentenyl group, a hexenyl group etc. are mentioned, Especially a vinyl group is preferable.
Examples of functional groups bonded to silicon atoms other than alkenyl groups include alkyl groups such as methyl, ethyl, propyl, and butyl groups, aryl groups such as phenyl and tolyl groups, benzyl groups, and phenethyl groups. Examples thereof include an aralkyl group, and a methyl group is particularly preferable.

(B) Functional groups bonded to silicon atoms other than hydrogen atoms in the component include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, aryl groups such as phenyl group and tolyl group, benzyl group and phenethyl. And an aralkyl group such as a group, and a methyl group is particularly preferable.
In addition, the content of the component (b) is preferably an amount such that the hydrogen atoms are in the range of 0.1 to 10 mol with respect to 1 mol of the total alkenyl groups contained in the component (a). The amount is preferably in the range of 0.1 to 5 mol, and more preferably in the range of 0.5 to 2 mol.

The catalyst for hydrosilylation reaction of component (c) is a catalyst for promoting a hydrosilylation reaction between an alkenyl group in component (a) and a hydrogen atom bonded to a silicon atom in component (b). Examples of such a catalyst include a platinum-based catalyst, a rhodium-based catalyst, a palladium-based catalyst, and the like, and a platinum-based catalyst is particularly preferable.
Examples of the platinum-based catalyst include fine platinum powder, chloroplatinic acid, platinum-olefin complex, platinum carbonyl complex and the like, and chloroplatinic acid is particularly preferable.

  Further, the content of the component (c) is an amount capable of promoting the curing of the composition, that is, hydrosilyl of an alkenyl group in the component (a) and a hydrogen atom bonded to a silicon atom in the component (b). There is no particular limitation as long as it is an amount capable of promoting the chemical reaction, and specifically, the metal atom in the present component is 0.01 to 500 ppm by weight with respect to the present composition. It is preferably within the range, more preferably within the range of 0.01 to 50 ppm.

The reason why the content of the metal atom in this component is limited as described above is that if the content is less than 0.01 ppm, the composition may not be sufficiently cured, while the content is This is because if it exceeds 500 ppm, the obtained cured product may have problems such as coloring.
About this silicone resin, unless the objective of this invention is impaired, you may contain a heat-resistant agent, dye, a pigment, a flame retardance imparting agent, etc. as other arbitrary components.

  Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, and other bifunctional glycidyl ether type epoxy resins, phenol novolac type Polyfunctional glycidyl ether type epoxy resin such as epoxy resin, orthocresol novolac type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, tris-hydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin, tetraglycidyldia Mini diphenylmethane type epoxy resin, triglycidyl isocyanurate type epoxy resin, aminophenol type epoxy resin, aniline type epoxy resin, toluidine type epoxy Glycidyl amine type epoxy resins such as a resin is preferably used.

  As a curing agent for epoxy resin, any of polyaddition type, catalyst type and condensation type can be used. For example, diaminodiphenylmethane, diaminodiphenylsulfone, polyamide, dicyandiamide, diethylenetriamine, triethylenetetramine, hexahydro anhydride Examples thereof include phthalic acid and methyltetrahydrophthalic anhydride.

As the acrylate resin, a monofunctional acrylate and / or a polyfunctional acrylate is used, and one or more of these are used.
Specific examples of the monofunctional acrylate and the polyfunctional acrylate will be described below.
(A) As an aliphatic monofunctional (meth) acrylate,
Alkyl (meth) acrylates such as butyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc. Alkoxyalkylene glycol (meth) acrylates such as methoxypropylene glycol (meth) acrylate and ethoxydiethylene glycol (meth) acrylate (meth) Examples include N-substituted acrylamides such as acrylamide and N-butoxymethyl (meth) acrylamide.

(B) As aliphatic polyfunctional (meth) acrylate,
1,6-hexanediol di (meth) acrylate, 1.4-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Alkylene glycol di (meth) such as glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polybutanediol di (meth) acrylate, etc. Acrylate Pentaerythritol triacrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide, propylene oxide modified trimethylolpropane triacrylate Examples include tetra (meth) acrylates such as tri (meth) acrylates such as dibasic ester, tetra (meth) acrylates such as di-trimethylolpropane tetraacrylate, and penta (meth) acrylates such as dipentaerythritol (monohydroxy) pentaacrylate.

(C) Among the alicyclic (meth) acrylates, the monofunctional type includes cyclohexyl (meth) acrylate, and the polyfunctional type includes dicyclopentadienyl di (meth) acrylate.
(D) Among aromatic (meth) acrylates, monofunctional types include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, and the like. Examples of the mold include diacrylates such as bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate, and the like.

(E) Examples of the polyurethane (meth) acrylate include polyurethane ether (meth) acrylate and polyester (meth) acrylate.
(F) Examples of the epoxy (meth) acrylate include bisphenol A type epoxy acrylate and novolac type epoxy acrylate.

  As radical polymerization initiators, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy Examples thereof include peroxide polymerization initiators such as pivalate, t-butyl peroxybenzoate, and t-butyl peroxyacetate, and azo polymerization initiators such as 2,2′-azobisisobutyronitrile.

  In addition, an antioxidant, a release agent, a coupling agent, an inorganic filler, and the like may be added to the silicone resin, epoxy resin, acrylate resin, and the like as long as the characteristics are not impaired.

In this transparent composite, the content of the alkaline earth metal oxide-doped zirconia nanoparticles is preferably 1% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and further preferably 10% by mass. It is not less than 50% by mass and not more than 50% by mass.
Here, the reason why the content of the alkaline earth metal oxide-doped zirconia nanoparticles is limited to 1% by mass or more and 80% by mass or less is that the lower limit of 1% by mass is a mechanical property such as refractive index and elastic modulus. This is because it is the minimum value of the addition rate that can improve the thermal characteristics such as heat resistance and thermal expansion coefficient. On the other hand, the upper limit of 80% by mass is the characteristic of the resin itself (flexibility, shape retention, etc. This is because it is the maximum value of the addition rate that can be maintained.

In this transparent composite, when the content of the alkaline earth metal oxide-doped zirconia nanoparticles is 25% by mass, the visible light transmittance is preferably 90% or more, more preferably 92% when the optical path length is 1 mm. % Or more.
The visible light transmittance varies depending on the content of the alkaline earth metal oxide-doped zirconia nanoparticles in the transparent composite. When the content of the alkaline earth metal oxide-doped zirconia nanoparticles is 1% by mass, the visible light transmittance is 95% or more. When the content of the earth metal oxide-doped zirconia nanoparticles is 40% by mass, it is 80% or more.

  Since the refractive index of the alkaline earth metal oxide-doped zirconia nanoparticles is 2.15, which is equivalent to the refractive index of the zirconia particles, the alkaline earth metal oxide-doped zirconia nanoparticles are dispersed in the resin. It is possible to increase the refractive index of various resins to be larger than the refractive index of the resin itself.

  The transparent composite of the present embodiment is a resin composition in which the above alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion and the above resin monomer or oligomer are mixed using a mixer or the like and are easy to flow. Then, the resin composition is molded using a mold, or filled in a mold or a container, and then the molded body or filler is heated or irradiated with ultraviolet rays, infrared rays, etc. It can be obtained by curing the body or filling.

  Of the dispersion media contained in the above alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion, water and organic solvents are usually mixed with alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion and resin. Thereafter, it is preferably removed by volatilization or the like. Examples of the removal method include vacuum (room temperature) drying and heat drying. Here, when the removal of the dispersion medium is insufficient, there may be a problem such as generation of bubbles when the resin is cured. On the other hand, when a liquid resin monomer or oligomer is used as the dispersion medium, the dispersion medium itself can be used as the resin component, which is preferable.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

"Example 1"
(Preparation and Evaluation of Alkaline Earth Metal Oxide Doped Zirconia Nanoparticle Transparent Dispersion)
To an aqueous zirconium salt solution in which 2615 g of zirconium oxychloride octahydrate was dissolved in 40 L (liter) of pure water, an aqueous ammonium hydrogen carbonate solution in which 896 g of ammonium hydrogen carbonate was dissolved in 11 L of pure water was added with stirring, and the zirconia precursor sol was added. Produced. The pH of this zirconia precursor sol was 2.4.
Next, 734.2 g of magnesium nitrate hexahydrate was added to this zirconia precursor sol and dissolved therein to prepare a zirconia precursor sol containing magnesium ions.

Next, a potassium carbonate aqueous solution in which 1000 g of potassium carbonate was dissolved in 35 L of pure water was added to the zirconia precursor sol with stirring to obtain a mixture. The amount of potassium carbonate added at this time was 100% by mass relative to the zirconia-converted value of zirconium ions in the zirconia precursor sol. The pH after addition of potassium carbonate was 11.5.
Next, this mixture was dried in the air at 130 ° C. for 24 hours using a dryer to obtain a solid.
Next, the solid was pulverized using an automatic mortar, and then baked (heated) in the air at 550 ° C. for 2 hours using an electric furnace to obtain a baked product.
Next, the fired product is put into pure water and stirred to form a slurry, which is then washed using a centrifugal separator, and the added potassium carbonate is sufficiently removed, followed by drying, and magnesia-doped zirconia. Nanoparticles were obtained.

  Next, 870 g of toluene as a dispersion medium and 30 g of 3-methacryloxypropyltrimethoxysilane as a dispersant (silane coupling agent) were added to 100 g of the magnesia-doped zirconia nanoparticles, and then a dispersion treatment was performed. A doped zirconia nanoparticle transparent dispersion (Z1) was prepared.

Subsequently, the dispersed particle diameter and visible light transmittance of this magnesia-doped zirconia nanoparticle transparent dispersion (Z1) were measured by the following methods.
(1) Dispersed particle size Using a dynamic light scattering particle size distribution measuring device (Malvern), the content of magnesia-doped zirconia nanoparticles in the transparent dispersion (Z1) is 1% by mass using toluene. A sample for measurement was prepared. The data analysis conditions were such that the particle diameter reference was volume reference, the refractive index of magnesia-doped zirconia nanoparticles as dispersion particles was 2.15, and the refractive index of toluene as a dispersion medium was 1.49.

(2) Visible light transmittance The sample which adjusted the content rate of the magnesia dope zirconia nanoparticle in said transparent dispersion liquid (Z1) to 5 mass% using toluene was put into a quartz cell (10 mm x 10 mm), and this sample The visible light transmittance when the optical path length was 10 mm was measured using a spectrophotometer (manufactured by JASCO Corporation). Here, the transmittance of 80% or more was “◯”, and the transmittance of less than 80% was “x”.

(Production and evaluation of transparent composite)
To 100 g of the above transparent dispersion (Z1), 8 g of epoxy resin: bisphenol A type epoxy resin j ER806 (manufactured by Japan Epoxy Resin Co., Ltd.) is added and dedispersed by vacuum drying to obtain a transparent resin composition. It was.
Next, 2 g of curing agent j ER LV11 (manufactured by Japan Epoxy Resin Co., Ltd.) was added to this resin composition, kneaded, and then poured into a mold assembled with a glass plate so that the thickness was 1 mm. Then, it was cured by heating at 150 ° C. for 30 minutes to obtain a transparent composite of Example 1.
The content of magnesia-doped zirconia nanoparticles in this transparent composite was 50% by mass.

This transparent composite was evaluated by the following apparatus or method for three points of visible light transmittance, refractive index, and durability.
(1) Visible light transmittance Visible light transmittance was measured using a spectrophotometer (manufactured by JASCO Corporation).
Here, the measurement sample was a bulk body having a size of 100 × 100 × 1 mm, the transmittance of 80% or more was “◯”, and the less than 80% was “×”.

(2) Refractive index Measured with an Abbe refractometer in accordance with Japanese Industrial Standards: JIS K 7142 “Plastic Refractive Index Measuring Method”
Here, on the basis of the resin not added with zirconia particles, a case where the refractive index is improved by 0.05 or more is indicated by “◯”, and a case where the refractive index is improved by less than 0.05 is indicated by “X”.
(3) Durability The color change after standing the transparent composite in a dryer at 120 ° C. for 100 hours, that is, the color difference (ΔE ^* ) is a colorimetric color difference meter ZE600 (manufactured by Nippon Denshoku Industries Co., Ltd.) ). These evaluation results are shown in Table 1.
A transmission electron microscope (TEM) image of the dispersed particles of this magnesia-doped zirconia nanoparticle transparent dispersion (Z1) is shown in FIG.

"Example 2"
(Preparation and Evaluation of Alkaline Earth Metal Oxide Doped Zirconia Nanoparticle Transparent Dispersion)
To an aqueous zirconium salt solution in which 2615 g of zirconium oxychloride octahydrate was dissolved in 40 L (liter) of pure water, an aqueous ammonium hydrogen carbonate solution in which 896 g of ammonium hydrogen carbonate was dissolved in 11 L of pure water was added with stirring, and the zirconia precursor sol was added. Produced. The pH of this zirconia precursor sol was 2.4.
Next, 1387 g of magnesium nitrate hexahydrate was added to this zirconia precursor sol and dissolved to prepare a zirconia precursor sol containing magnesium ions.

Next, a potassium carbonate aqueous solution in which 1000 g of potassium carbonate was dissolved in 35 L of pure water was added to the zirconia precursor sol with stirring to obtain a mixture. The amount of potassium carbonate added at this time was 100% by mass with respect to the zirconia converted value of zirconium ions in the zirconia precursor sol. The pH after addition of potassium carbonate was 11.5.
Next, this mixture was dried in the air at 130 ° C. for 24 hours using a dryer to obtain a solid.
Next, the solid was pulverized using an automatic mortar, and then baked (heated) in the air at 550 ° C. for 2 hours using an electric furnace to obtain a baked product.
Next, the fired product is put into pure water and stirred to form a slurry, which is then washed using a centrifugal separator, and the added potassium carbonate is sufficiently removed, followed by drying, and magnesia-doped zirconia. Nanoparticles were obtained.

  Next, 870 g of toluene as a dispersion medium and 30 g of 3-methacryloxypropyltrimethoxysilane as a dispersant (silane coupling agent) were added to 100 g of the magnesia-doped zirconia nanoparticles, and then a dispersion treatment was performed. A doped zirconia nanoparticle transparent dispersion (Z2) was prepared.

Subsequently, the dispersed particle diameter and visible light transmittance of the magnesia-doped zirconia nanoparticle transparent dispersion (Z2) were measured according to Example 1.
Further, using this magnesia-doped zirconia nanoparticle transparent dispersion (Z2), a transparent composite of Example 2 was obtained according to Example 1.
The content of magnesia-doped zirconia nanoparticles in this transparent composite was 50% by mass.
This transparent composite was evaluated according to Example 1. These evaluation results are shown in Table 1.

“Comparative Example 1”
(Preparation and evaluation of zirconia nanoparticle transparent dispersion)
To an aqueous zirconium salt solution in which 2615 g of zirconium oxychloride octahydrate was dissolved in 40 L (liter) of pure water, an aqueous ammonium hydrogen carbonate solution in which 896 g of ammonium hydrogen carbonate was dissolved in 11 L of pure water was added with stirring, and the zirconia precursor sol was added. Produced. The pH of this zirconia precursor sol was 2.4.

Next, a potassium carbonate aqueous solution in which 1000 g of potassium carbonate was dissolved in 35 L of pure water was added to the zirconia precursor sol with stirring to obtain a mixture. The amount of potassium carbonate added at this time was 100% by mass relative to the zirconia-converted value of zirconium ions in the zirconia precursor sol. The pH after addition of potassium carbonate was 11.5.
Subsequently, this mixture was dried at 130 ° C. for 24 hours in the air using a dryer to obtain a solid.
Next, the solid was pulverized using an automatic mortar, and then baked (heated) in the air at 550 ° C. for 2 hours using an electric furnace to obtain a baked product.
Next, the fired product is put into pure water, stirred to form a slurry, and then washed using a centrifugal separator. After sufficiently removing the added potassium carbonate, the product is dried to obtain zirconia nanoparticles. Got.

  Next, 870 g of toluene as a dispersion medium and 30 g of 3-methacryloxypropyltrimethoxysilane as a dispersant (silane coupling agent) were added to 100 g of the zirconia nanoparticles, and then a dispersion treatment was performed. A transparent dispersion (Z3) was prepared.

Subsequently, the dispersed particle diameter and visible light transmittance of this zirconia nanoparticle transparent dispersion (Z3) were measured according to Example 1.
Furthermore, using this zirconia nanoparticle transparent dispersion (Z3), a transparent composite of Comparative Example 1 was obtained according to Example 1.
The content of zirconia nanoparticles in the transparent composite was 50% by mass.
This transparent composite was evaluated according to Example 1. These evaluation results are shown in Table 1.

According to these evaluation results, in Examples 1 and 2, it was found that the visible light transmittance, refractive index, and durability were all good.
On the other hand, in Comparative Example 1, the visible light transmittance and refractive index are not inferior to those of Examples 1 and 2, but the durability is higher than that of Examples 1 and 2 with a color difference (ΔE ^* ) of 8.3. And it was recognized visually that it yellowed clearly and was inferior compared with Example 1,2.

  The alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion of the present invention is an alkaline earth metal oxide-doped zirconia having a dispersed particle diameter of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia. By dispersing the nanoparticles in the dispersion medium, it is possible not only to achieve both high refractive index and high transparency, but also to improve durability. A transparent composite produced using this transparent dispersion is a semiconductor laser (LD) or light emitting diode (LED) sealing material, a liquid crystal display substrate, an organic EL display substrate, a color filter substrate, a touch panel. It is useful as an optical sheet, a transparent plate, an optical lens, an optical element, an optical waveguide, etc., such as an optical substrate, a solar cell substrate, and the industrial effect is great.

Claims (4)

  An alkali characterized by dispersing alkaline earth metal oxide-doped zirconia nanoparticles having a dispersed particle diameter of 1 nm or more and 20 nm or less obtained by dissolving an alkaline earth metal oxide in zirconia in a dispersion medium. Transparent dispersion of earth metal oxide doped zirconia nanoparticles.   2. The alkaline earth metal oxide-doped zirconia nanoparticle transparent dispersion according to claim 1, wherein the content of the alkaline earth metal oxide-doped zirconia nanoparticle is 1% by mass to 70% by mass. .   A transparent composite characterized in that alkaline earth metal oxide-doped zirconia nanoparticles having a dispersed particle size of 1 nm or more and 20 nm or less formed by dissolving an alkaline earth metal oxide in zirconia are dispersed in a resin. body.   The transparent composite according to claim 3, wherein the content of the alkaline earth metal oxide-doped zirconia nanoparticles is 1% by mass or more and 80% by mass or less.