JP2008120848A - Transparent inorganic oxide dispersion, transparent composite, method for producing the same, composition for sealing light-emitting element and light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a transparent inorganic oxide dispersion that is obtained by modifying the surface of an inorganic oxide fine particle with a surface modifying agent containing at least one functional group of functional groups of a resin, has an improved refractive index and mechanical properties and maintains transparency and a transparent composite material; to provide a method for producing the transparent composite material; and to obtain a composition for sealing a light-emitting element and the light-emitting element. <P>SOLUTION: The transparent inorganic oxide dispersion is a transparent inorganic oxide dispersion useful for dispersing an inorganic oxide fine particle into a resin. The surface of the inorganic oxide fine particle is modified with the surface modifying agent containing at least one functional group of the functional groups of the resin and the inorganic oxide fine particle has an average dispersion particle diameter of ≥1 nm and ≤20 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

 The present invention relates to a transparent inorganic oxide dispersion and a transparent composite, a method for producing the same, a composition for sealing a light-emitting element, and a light-emitting element. More specifically, the present invention is suitably used as a filler material for a resin. Inorganic oxide transparent dispersion capable of maintaining transparency while improving the transparency, a transparent composite composite-integrated by improving the compatibility of the inorganic oxide transparent dispersion with a resin, and the transparent composite The manufacturing method of this, the composition for light emitting element sealing formed by disperse | distributing inorganic oxide microparticles | fine-particles in resin, and a light emitting element using the same.

 Conventionally, attempts have been made to improve the mechanical properties of a resin by combining it with a resin using an inorganic oxide such as silica as a filler. As a method of combining the filler and the resin, a method of mixing a dispersion in which an inorganic oxide is dispersed in water and / 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 a second phase can be produced (for example, see Patent Document 1).

 On the other hand, light-emitting diodes that are light-emitting elements used in optical semiconductor devices such as optical pickups used in CDs, CD-ROMs, CD-Videos, MOs, CD-Rs, DVDs, various display devices, display devices, etc. As a resin composition for sealing an optical semiconductor element such as (LED: light emitting diode), the cured product is required to have transparency, and is generally bisphenol A type epoxy resin or alicyclic type. A resin composition composed of an epoxy resin such as an epoxy resin and an acid anhydride curing agent is widely used (see, for example, Patent Document 2).

However, while white LEDs are attracting attention, problems that have not been considered so far have occurred. Such problems include, for example, the yellowing of the epoxy sealing material due to ultraviolet rays or the like during the practical use of the LED, and the occurrence of cracks in the epoxy sealing material with an increase in the amount of heat generated due to the downsizing of the LED. Is mentioned.
In order to solve these problems, it has been studied to convert a sealing resin composition into a silicone resin with little characteristic deterioration due to light damage. While the refractive index of the epoxy resin is 1.58, the refractive index of the silicone resin is as low as 1.40. Therefore, the required properties for the silicone resin for LED applications are maintained with transparency and mechanical properties. It is mentioned that the refractive index is improved as it is (see, for example, Patent Document 3).

In addition, for the purpose of improving the refractive index of plastic materials, mixing of inorganic oxide particles such as zirconia and titania into plastic materials or mixing with plastic materials has been studied. In addition, in order to make inorganic oxide particles complex with resin, a dispersion liquid in which inorganic oxide particles are dispersed in an aqueous solvent or an organic solvent has been developed, and improvement of the refractive index of resin materials has been studied (for example, , See Patent Document 4).
Japanese Patent Laying-Open No. 2005-161111 JP 2001-085748 A Japanese Patent Laying-Open No. 2005-093724 JP 2005-327777 A

By the way, when trying to combine conventional inorganic oxide particles with a hydrophobic resin, the surface of the inorganic oxide particles is hydrophilic, and therefore, particularly between a highly hydrophobic silicone resin and inorganic oxide particles. However, there is a problem that it is difficult to separate and combine the silicone resin and the inorganic oxide particles.
Therefore, as a general solution, in order to hydrophobize the surface of the inorganic oxide particles, a surface modifier such as an organic polymer dispersant is applied to the surface of the inorganic oxide particles to thereby form a silicone resin and an inorganic oxide. The device which raises the compatibility with a physical particle is made | formed. However, until the inorganic oxide particles are compatible with the silicone resin, it is difficult to make the surface hydrophobic, and since the inorganic oxide particles have a large particle size of 20 nm or more, the transparency is lowered. There was a problem that it was not transparent.

 The present invention has been made in order to solve the above-described problems, and the surface of the inorganic oxide fine particles is modified with a surface modifier having at least one functional group among the functional groups of the resin. It is an object of the present invention to provide an inorganic oxide transparent dispersion and a transparent composite, a method for producing the same, a composition for sealing a light-emitting element, and a light-emitting element that can maintain transparency while improving the rate and mechanical properties.

 As a result of intensive studies to solve the above problems, the present inventors have found that the surface of inorganic oxide fine particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less is a functional group of a resin that disperses the inorganic oxide fine particles. If the surface is modified with a surface modifying agent having at least one functional group, and the inorganic oxide fine particles whose surface is modified are dispersed in the dispersion liquid to form an inorganic oxide transparent dispersion liquid, then composite with the resin The inventors have found that it is possible to improve the refractive index and mechanical properties while maintaining the transparency of the composite, and have completed the present invention.

 That is, the inorganic oxide transparent dispersion of the present invention is an inorganic oxide transparent dispersion used for dispersing inorganic oxide fine particles in a resin, and has at least one functional group among the functional groups of the resin. It is characterized in that it comprises inorganic oxide fine particles whose surface is modified by a surface modifier having an average dispersed particle diameter of 1 nm or more and 20 nm or less.

 The surface modifier is one selected from the group of vinyl group, styryl group, acrylic group, methacryl group, acryloxy group, epoxy group, carbon-carbon double bond, phenyl group, methylphenyl group, silicon-hydrogen bond. Or it is preferable to have 2 or more types.

The weight ratio of the modified portion on the surface is preferably 5% by weight or more and 200% by weight or less of the inorganic oxide fine particles.
The inorganic oxide fine particles are preferably zirconium oxide or titanium oxide.
The resin is preferably a silicone resin, a modified silicone resin or an acrylic resin.

 The transparent composite of the present invention comprises inorganic oxide fine particles whose surface is modified with a surface modifier having at least one functional group of the resin in the resin and whose average dispersed particle size is 1 nm or more and 20 nm or less. It is characterized by being dispersed.

 The content of the inorganic oxide fine particles is preferably 1% by weight or more and 90% by weight or less.

 The method for producing a transparent composite of the present invention comprises mixing the inorganic oxide transparent dispersion of the present invention and a resin, molding or filling the resulting mixture, and then curing the molded body or the filling. It is characterized by.

 The composition for sealing a light emitting device of the present invention is a composition for sealing a light emitting device using the inorganic oxide transparent dispersion of the present invention, and the inorganic oxide fine particles have an average dispersed particle size in the resin. It is characterized by being dispersed at 1 nm or more and 20 nm or less.

 The light emitting device of the present invention is characterized in that at least a light transmission region is sealed with the composition for sealing a light emitting device of the present invention.

According to the inorganic oxide transparent dispersion of the present invention, the inorganic oxide transparent dispersion used for dispersing the inorganic oxide fine particles in the resin, wherein at least one functional group among the functional groups of the resin is present. Since the surface is modified by the surface modifying agent and the inorganic oxide fine particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less are contained, the affinity between the resin and the inorganic oxide fine particles can be increased. Dispersion and compatibility with highly hydrophobic silicone resin, modified silicone resin, acrylic resin, etc. used in LED sealing resin compositions, etc. are possible. Can be maintained.
Therefore, when the inorganic oxide transparent dispersion of the present invention is mixed with a resin, a transparent composite having a high refractive index, excellent transparency, and improved mechanical properties can be easily obtained.
In addition, according to the inorganic oxide transparent dispersion of the present invention, it is possible to obtain a composite of a filler and a resin without involving a complicated reaction such as a polymerization reaction that has been conventionally required. Furthermore, a composite of a filler and a resin can be obtained safely and easily without worrying about heat generation due to a polymerization initiator or the like.

 According to the transparent composite of the present invention, the surface of the resin is modified with a surface modifier having at least one functional group among the functional groups of the resin, and the average dispersed particle diameter is 1 nm or more and 20 nm or less. Since the fine particles are dispersed, the refractive index, transparency and mechanical properties can be improved.

 According to the method for producing a transparent composite of the present invention, the inorganic oxide transparent dispersion of the present invention and a resin are mixed, the resulting mixture is molded or filled, and then the molded or filled is cured. Therefore, a transparent composite having a high refractive index, excellent transparency, and improved mechanical properties can be produced easily and inexpensively.

The best mode of the inorganic oxide transparent dispersion liquid and transparent composite of the present invention, a method for producing the same, a composition for sealing a light emitting device, and a light emitting device using the same will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

"Inorganic oxide transparent dispersion"
The inorganic oxide transparent dispersion of the present invention is an inorganic oxide transparent dispersion used for dispersing inorganic oxide fine particles in a resin, and is a functional group of the resin for compatibility (uniform dispersion). Among these, the dispersion liquid includes inorganic oxide fine particles having a surface modified by a surface modifier having at least one functional group and an average dispersed particle diameter of 1 nm or more and 20 nm or less, and a dispersion medium.

The inorganic oxide fine particles are not particularly limited, but zirconia (Zr), titanium (Ti), silicon (Si), aluminum (Al), iron (Fe), copper (Cu), zinc (Zn), yttrium (Y ), Niobium (Nb), molybdenum (Mo), indium (In), tin (Sn), tantalum (Ta), tungsten (W), lead (Pb), bismuth (Bi), cerium (Ce), antimony (Sb) ), And oxides of elements such as germanium (Ge) are used.
Examples of oxides of these elements include zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ , FeO). , Fe ₃ O ₄ ), copper oxide (CuO, Cu ₂ O), zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), molybdenum oxide (MoO ₃ ), indium oxide (In ₂ O ₃ , In ₂ O), tin oxide (SnO ₂ ), tantalum oxide (Ta ₂ O ₅ ), tungsten oxide (WO ₃ , W ₂ O ₅ ), lead oxide (PbO, PbO ₂ ), bismuth oxide (Bi ₂ O ₃ ), cerium oxide (CeO ₂ , Ce ₂ O ₃ ), antimony oxide (Sb ₂ O ₅ , Sb ₂ O ₅ ) germanium oxide (GeO ₂ , GeO) Etc. In particular, zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ) that enhance compatibility with the resin are preferable.

As the surface modifier, one kind selected from the group of vinyl group, styryl group, acrylic group, methacryl group, acryloxy group, epoxy group, carbon-carbon double bond, phenyl group, methylphenyl group, silicon-hydrogen bond Or what has 2 or more types is used suitably.
Examples of such surface modifiers include alkoxysilane compounds and siloxane compounds.
Of these surface modifiers, a silane coupling agent is particularly preferable as the alkoxysilane compound, and a straight silicone resin and a modified silicone resin are preferable as the siloxane compound.

 Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriphenoxysilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, p-styryltriphenoxysilane, and 3-acryloxypropyl. Trimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyltriphenoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltriphenoxysilane, 3 -Aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, Rutriphenoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxy Examples include silane, n-decyltrimethoxysilane, phenyltrimethoxysilane, and diphenyldimethoxysilane.

Examples of the straight silicone resin include methyl silicone resin, dimethyl silicone resin, and methylphenyl silicone resin.
Examples of the modified silicone resin include methoxy modified silicone resin, alkyd modified silicone resin, acrylic modified silicone resin, polyester modified silicone resin, carboxy modified silicone resin, alcohol modified silicone resin, polyether modified silicone resin, epoxy modified silicone resin, mercapto modified silicone. Resins, amino-modified silicone resins, methacrylate-modified silicone resins and the like can be mentioned.

Examples of the method for modifying the surface of the inorganic oxide fine particles using the surface modifier include a wet method and a dry method.
The wet method is a method for modifying the surface of the inorganic oxide fine particles by adding and mixing the surface modifier and the inorganic oxide fine particles in a solvent.
The dry method is a method of modifying the surface of the inorganic oxide fine particles by putting the surface modifier and the dried inorganic oxide fine particles into a dry mixer such as a mixer and mixing them.

The weight ratio of the modified portion of the surface-modified inorganic oxide fine particles is preferably 5% by weight or more and 200% by weight or less, more preferably 10% by weight or more and 100% by weight or less, More preferably, it is 20 weight% or more and 100 weight% or less.
Here, the reason for limiting the weight ratio of the modified portion to 5 wt% or more and 200 wt% or less is that if the weight ratio of the modified portion is less than 5 wt%, the inorganic oxide fine particles are difficult to be compatible with the resin. This is because the transparency is lost when compounding with the resin. On the other hand, if the weight ratio of the modified portion exceeds 200% by weight, the effect of the surface treatment agent on the resin properties increases, and the refractive index, etc. This is because the composite properties of the above deteriorate.

The reason why the average dispersed particle size of the inorganic oxide fine particles is limited to 1 nm or more and 20 nm or less is that when the average dispersed particle size is less than 1 nm, the crystallinity becomes poor and the particle characteristics such as refractive index are exhibited. On the other hand, when the average dispersed particle size of the inorganic oxide fine particles exceeds 20 nm, the transparency is lowered when a dispersion or a transparent composite is formed.
As described above, since the inorganic oxide fine particles are nano-sized particles, even when the inorganic oxide fine particles are dispersed in the resin to form a transparent composite, light scattering is small, and the transparency of the composite is reduced. It is possible to maintain.

The content of the inorganic oxide fine particles is preferably 1% by weight or more and 80% by weight or less, more preferably 1% by weight or more and 50% by weight or less, and further preferably 5% by weight or more and 30% by weight or less.
Here, the reason why the content of the inorganic oxide fine particles is limited to 1% by weight or more and 80% by weight or less is that this range is a range in which the inorganic oxide fine particles can be well dispersed, and the content is 1% by weight. This is because if it is less than%, the effect as inorganic oxide fine particles is lowered, and if it exceeds 80% by weight, gelation and aggregation precipitation occur, and the characteristics as a dispersion are lost.

The dispersion medium basically contains at least one of water, an organic solvent, a liquid resin monomer, and a liquid resin oligomer.
Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol, butanol, and octanol; ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and γ-butyrolactone. Esters such as 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, diethylene glycol monoethyl ether; acetone, Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, cyclohexanone Any ketones; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; amides such as dimethylformamide, N, N-dimethylacetoacetamide, and N-methylpyrrolidone are preferably used, and one of these solvents Or 2 or more types 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.

In addition to the above, this inorganic oxide transparent dispersion may contain other inorganic oxide particles, resin monomers, and the like as long as the characteristics are not impaired.
Examples of inorganic oxide particles other than the above include monoclinic or cubic zirconia particles, or metal composite oxides such as antimony-added tin oxide (ATO) and tin-added indium oxide (ITO).

In this inorganic oxide transparent dispersion, when the content of the inorganic oxide fine particles is 5% by weight, the visible light transmittance is preferably 90% or more, more preferably 95% or more when the optical path length is 10 mm. is there.
The visible light transmittance varies depending on the content of the inorganic oxide fine particles, and is 95% or more when the content of the inorganic oxide fine particles is 1% by weight, and 80% or more when the content of the inorganic oxide fine particles is 40% by weight. .

"Transparent composite"
The transparent composite of the present invention comprises inorganic oxide fine particles whose surface is modified with a surface modifier having at least one functional group among the functional groups of the resin and whose average dispersed particle diameter is 1 nm or more and 20 nm or less. Is a composite in which is dispersed.
The resin may be a 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 silicone resins such as dimethyl silicone resin, methylphenyl silicone resin, and methylhydrogen silicone resin, modified silicone resins, acrylic resins such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate, and polycarbonate (PC). , Polystyrene (PS), polyether, polyester, polyarylate, polyacrylate, polyamide, phenol-formaldehyde (phenol resin), diethylene glycol bisallyl carbonate, acrylonitrile / styrene copolymer (AS resin), methyl methacrylate / styrene Copolymer (MS resin), poly-4-methylpentene, norbornene-based polymer, polyurethane and the like are particularly preferable. , Modified silicone resin, an acrylic resin.

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

(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.
Moreover, examples of the functional group bonded to the silicon atom other than the alkenyl group 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 group. 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, and a palladium-based catalyst, and a platinum-based catalyst is particularly preferable.
Examples of the platinum catalyst include platinum fine 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.
Modified silicone resins include methoxy modified silicone, carboxy modified silicone, alcohol modified silicone, polyether modified silicone, epoxy modified silicone, mercapto modified silicone, amino modified silicone, methacrylate modified silicone, methyl hydrogen silicone, alkyd modified silicone, acrylic modified. Examples include silicone and polyester-modified silicone.

As the acrylic resin, monofunctional acrylates and / or polyfunctional acrylates are used, and one or more of these are used.
Specific examples of the monofunctional acrylate and the polyfunctional acrylate will be described below.
(A) Examples of aliphatic monofunctional (meth) acrylates include alkyl (meth) acrylates such as butyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate; methoxypropylene glycol (meth) acrylate, ethoxydiethylene glycol ( Examples include alkoxyalkylene glycol (meth) acrylates such as (meth) acrylate; N-substituted acrylamides such as (meth) 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 glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polybutanediol Alkylene glycol di (meth) acrylates such as di (meth) acrylate; pentaerythritol triacrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide, propylene Tri (meth) acrylates such as oxide-modified trimethylolpropane triacrylate; tetra (meth) acrylates such as pentaerythritol tetraacrylate and di-trimethylolpropane tetraacrylate; penta (meth) such as dipentaerythritol (monohydroxy) pentaacrylate An acrylate etc. are mentioned.

(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 novolak type epoxy acrylate.

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

In this transparent composite, the content of the inorganic oxide fine particles is preferably 1% by weight or more and 90% by weight or less, more preferably 10% by weight or more and 80% by weight or less, and further preferably 10% by weight or more and 50% by weight. % Or less.
Here, the reason why the content of the inorganic oxide fine particles is limited to 1% by weight or more and 90% by weight or less is that the lower limit value of 1% by weight is the minimum value of the addition rate that can improve the refractive index and mechanical properties. On the other hand, 90% by weight of the upper limit is the maximum value of the addition rate that can maintain the characteristics (flexibility and specific gravity) of the resin itself.

In this transparent composite, when the content of the inorganic oxide fine particles is 25% by weight, the visible light transmittance is preferably 90% or more, more preferably 92% or more when the optical path length is 1 mm.
This visible light transmittance varies depending on the content of the inorganic oxide fine particles in the transparent composite, and is 95% or more when the content of the inorganic oxide fine particles is 1% by weight, and 80 when the content of the inorganic oxide fine particles is 40% by weight. % Or more.

Among the inorganic oxide fine particles, the refractive index of tetragonal zirconia particles is 2.15. By dispersing this tetragonal zirconia particles in the resin, the refractive index of acrylic resin and silicone resin is about 1.4, epoxy Compared with a resin having a refractive index of about 1.5, the refractive index of the resin can be further improved.
Further, since the tetragonal zirconia particles are nano-sized particles, even when they are combined with a resin, light scattering is small and the transparency of the composite material can be maintained.

"Production method of transparent composite"
The transparent composite of the present invention can be produced by the following method.
First, the above-described inorganic oxide transparent dispersion of the present invention and a resin monomer or oligomer are mixed using a mixer or the like to obtain a resin composition in an easy-to-flow state.
Next, the resin composition is molded using a mold, or filled in a mold or a container, and then the molded body or filling is heated or irradiated with ultraviolet rays, infrared rays, or the like. The filling is cured.

Here, when the resin monomer or oligomer has a reactive carbon double bond (C = C), it can be polymerized / resinized simply by mixing.
In particular, there are various methods for curing a resin composition containing an ultraviolet (UV) curable resin such as an acrylic resin. Typically, a radical polymerization reaction initiated by heating or light irradiation is used. Mold molding method, transfer molding method and the like. Examples of this radical polymerization reaction include a polymerization reaction by heat (thermal polymerization), a polymerization reaction by light such as ultraviolet rays (photopolymerization), a polymerization reaction by gamma (γ) rays, or a combination of these. .

 An example of the transparent composite of the present invention is an optical element made of a silicone resin. This optical element is manufactured by putting one or a plurality of types of organopolysiloxane, a curing agent, and a catalyst into a mold and thermally curing in the mold to obtain a molded body having a predetermined shape. As the thermosetting reaction, reactions such as condensation crosslinking, peroxide crosslinking, and platinum addition crosslinking can be used. In particular, thermosetting by an addition polymerization reaction using a platinum catalyst is preferable.

“Light Emitting Element Sealing Composition”
The composition for sealing a light emitting device of the present invention uses the inorganic oxide transparent dispersion of the present invention, and the above inorganic oxide fine particles are dispersed in the above resin with an average dispersed particle size of 1 nm or more and 20 nm or less. Is a composition.

"Light emitting element"
The light emitting device of the present invention is a device formed by sealing at least a light transmission region with the composition for sealing a light emitting device of the present invention. Examples of such light emitting elements include LEDs.

 EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

[Preparation of zirconia transparent dispersion and transparent composite]
"Example 1"
To a zirconium salt solution in which 2615 g of zirconium oxychloride octahydrate is dissolved in 40 L (liter) of pure water, dilute ammonia water in which 344 g of 28% ammonia water is dissolved in 20 L of pure water is added with stirring, and the zirconia precursor slurry is added. It was adjusted.
Next, an aqueous sodium sulfate solution in which 300 g of sodium sulfate was dissolved in 5 L of pure water was added to this slurry with stirring. The amount of sodium sulfate added at this time was 30% by weight with respect to the zirconia converted value of zirconium ions in the zirconium salt solution.

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 with an automatic mortar or the like and then baked at 500 ° C. for 1 hour in the air using an electric furnace.
Next, the fired product is put into pure water, stirred to form a slurry, washed using a centrifuge, and after sufficiently removing the added sodium sulfate, dried in a dryer, Zirconia particles were prepared.

Next, 70 g of toluene as a dispersion medium and 10 g of methacryloxypropyltrimethoxysilane which is a silane coupling agent containing an acrylic group as a surface modifier are added to and mixed with 20 g of the zirconia particles, and the surface of the zirconia particles is surface-modified. Modified with agent.
Thereafter, a dispersion treatment was performed to prepare a zirconia transparent dispersion (Z1) of Example 1.

Next, 20 g of acryl-modified silicone was added to 100 g of this zirconia transparent dispersion (Z1), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with a glass plate so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S1).
The zirconia content of this transparent composite was 50% by weight.

"Example 2"
Particle synthesis was performed according to Example 1 to prepare zirconia particles.
Next, 70 g of toluene as a dispersion medium and 10 g of methylphenyl silicone resin, which is a silicone resin containing a phenyl group, are added to and mixed with 20 g of the zirconia particles, and the surface of the zirconia particles is modified with the surface modifier. .
Thereafter, dispersion treatment was performed to prepare a zirconia transparent dispersion (Z2) of Example 2.
Next, 20 g of methylphenyl silicone was added to 100 g of this zirconia transparent dispersion (Z2), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S2).
The zirconia content of this transparent composite was 50% by weight.

"Example 3"
Particle synthesis was performed according to Example 1 to prepare zirconia particles.
Next, 70 g of toluene as a dispersion medium and 10 g of methyl silicone resin, which is a straight silicone resin having a methyl group, were added to and mixed with 20 g of the zirconia particles, and the surface of the zirconia particles was modified with the surface modifier.
Thereafter, dispersion treatment was performed to prepare a zirconia transparent dispersion liquid (Z3) of Example 3.
Next, 20 g of dimethyl silicone was added to 100 g of this zirconia transparent dispersion (Z3), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S3).
The zirconia content of this transparent composite was 50% by weight.

"Comparative Example 1"
20 g of methylphenyl silicone was added to 100 g of the zirconia transparent dispersion (Z1), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with a glass plate so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S4).
The zirconia content of this transparent composite was 50% by weight.

"Comparative Example 2"
20 g of dimethyl silicone was added to 100 g of zirconia transparent dispersion (Z1), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm, and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S5).
The zirconia content of this transparent composite was 50% by weight.

“Comparative Example 3”
20 g of acryl-modified silicone was added to 100 g of the zirconia transparent dispersion (Z2), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S6).
The zirconia content of this transparent composite was 50% by weight.

“Comparative Example 4”
20 g of dimethyl silicone was added to 100 g of the zirconia transparent dispersion (Z2), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S7).
The zirconia content of this transparent composite was 50% by weight.

“Comparative Example 5”
20 g of acryl-modified silicone was added to 100 g of zirconia transparent dispersion (Z3), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with a glass plate so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S8).
The zirconia content of this transparent composite was 50% by weight.

“Comparative Example 6”
20 g of methylphenyl silicone was added to 100 g of the zirconia transparent dispersion (Z3), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S9).
The zirconia content of this transparent composite was 50% by weight.

“Comparative Example 7”
Particle synthesis was performed according to Example 1 to prepare zirconia particles.
Next, 70 g of toluene as a dispersion medium and 10 g of hexyltrimethoxysilane having a saturated hydrocarbon group as a surface modifier were added to and mixed with 20 g of the zirconia particles, and the surface of the zirconia particles was modified with the surface modifier.
Thereafter, dispersion treatment was performed to prepare a zirconia transparent dispersion liquid (Z4) of Comparative Example 7.
Next, 20 g of acryl-modified silicone was added to 100 g of this zirconia transparent dispersion (Z4), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S10).
The zirconia content of this transparent composite was 50% by weight.

"Comparative Example 8"
20 g of methylphenyl silicone was added to 100 g of zirconia transparent dispersion (Z4), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm, and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S11).
The zirconia content of this transparent composite was 50% by weight.

"Comparative Example 9"
20 g of dimethyl silicone was added to 100 g of the zirconia transparent dispersion (Z4), and the solvent was removed at room temperature under reduced pressure to prepare a resin composition.
Next, this resin composition was poured into a mold assembled with glass plates so as to have a thickness of 1 mm and cured by heating at 100 ° C. for 1 hour to obtain a transparent composite (S12).
The zirconia content of this transparent composite was 50% by weight.

[Evaluation of zirconia transparent dispersion]
The average dispersion particle diameter of the zirconia particles of the zirconia transparent dispersions of Examples 1 to 3 and Comparative Examples 1 to 9 and the visible light transmittance of the dispersions were measured.
The average dispersed particle size was measured using a dynamic light scattering particle size distribution measuring device (Malvern) and the zirconia particle content in the zirconia transparent dispersion was adjusted to 1% by weight. The data analysis conditions were such that the particle diameter standard was a volume standard, the refractive index of zirconia as a dispersed particle was 2.15, and the refractive index of toluene as a dispersion medium was 1.49. Here, the case where the average dispersed particle diameter was 1 nm or more and 20 nm or less was “◯”, and the others were “X”.

Further, the visible light transmittance of the dispersion is such that a sample prepared by adjusting the zirconia content of the above dispersion to 5% by weight using toluene is placed in a quartz cell (10 mm × 10 mm), and the optical path length of this sample is 10 mm. The visible light transmittance 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”.
The measurement results are shown in Tables 1 and 2.

"Evaluation of transparent composites"
About the transparent composites of Examples 1 to 3 and Comparative Examples 1 to 9, the visible light transmittance and the refractive index were evaluated by the following apparatus or method.
(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 “×”.
The measurement results are shown in Tables 1 and 2.

(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 to which zirconia is not added, 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”.
The measurement results are shown in Tables 1 and 2.

According to these evaluation results, in Examples 1 to 3, it was found that both the visible light transmittance and the refractive index were good.
On the other hand, in Comparative Examples 1 to 9, all the properties of visible light transmittance and refractive index were inferior to those of Examples 1 to 3.

The inorganic oxide transparent dispersion of the present invention is an inorganic oxide transparent dispersion used for dispersing inorganic oxide fine particles in a resin, and has a surface having at least one functional group among the functional groups of the resin. Improvement of refractive index and mechanical properties of transparent composite containing inorganic oxide fine particles and resin by containing inorganic oxide fine particles whose surface is modified by a modifier and having an average dispersed particle diameter of 1 nm or more and 20 nm or less In addition, since transparency can be maintained, a semiconductor laser (LED) sealing material, a substrate for a liquid crystal display device, a substrate for an organic EL display device, a substrate for a color filter, a substrate for a touch panel, and a solar cell The effect is great not only for optical sheets such as substrates, transparent plates, optical lenses, optical elements, optical waveguides, but also in various other industrial fields. That.

Claims (11)

An inorganic oxide transparent dispersion used for dispersing inorganic oxide fine particles in a resin,
Inorganic oxidation characterized by comprising inorganic oxide fine particles whose surface is modified by a surface modifier having at least one functional group among the functional groups of the resin and whose average dispersed particle diameter is 1 nm or more and 20 nm or less Transparent dispersion.  The surface modifier is one selected from the group of vinyl group, styryl group, acrylic group, methacryl group, acryloxy group, epoxy group, carbon-carbon double bond, phenyl group, methylphenyl group, silicon-hydrogen bond. Or it has 2 or more types, The inorganic oxide transparent dispersion liquid of Claim 1 characterized by the above-mentioned.  3. The inorganic oxide transparent dispersion according to claim 1, wherein the weight ratio of the modified portion on the surface is 5 wt% or more and 200 wt% or less of the inorganic oxide fine particles.  The inorganic oxide transparent dispersion according to any one of claims 1 to 3, wherein the content of the inorganic oxide fine particles is 1 wt% or more and 80 wt% or less.  The inorganic oxide transparent dispersion according to any one of claims 1 to 4, wherein the inorganic oxide fine particles are zirconium oxide or titanium oxide.  The inorganic oxide transparent dispersion according to any one of claims 1 to 5, wherein the resin is a silicone resin, a modified silicone resin, or an acrylic resin.  The surface is modified with a surface modifier having at least one functional group among the functional groups of the resin, and inorganic fine particles having an average dispersed particle diameter of 1 nm or more and 20 nm or less are dispersed in the resin. Transparent composite.  8. The transparent composite according to claim 7, wherein the content of the inorganic oxide fine particles is 1% by weight or more and 90% by weight or less.  Mixing the inorganic oxide transparent dispersion according to any one of claims 1 to 6 with a resin, molding or filling the resulting mixture, and then curing the molded body or the filling. A method for producing a transparent composite. A composition for sealing a light emitting device using the inorganic oxide transparent dispersion according to any one of claims 1 to 6,
A composition for sealing a light emitting device, wherein the inorganic oxide fine particles are dispersed in the resin at an average dispersed particle diameter of 1 nm or more and 20 nm or less. A light emitting device comprising at least a light transmission region sealed with the composition for sealing a light emitting device according to claim 10.