JP6648376B2 - Optical composition, thin film, molded product and optical device - Google Patents

Description

The present invention relates to an optical composition, a thin film or molded article obtained using the optical composition, and an optical device provided with the thin film or molded article.

In recent years, in the field of optical materials such as lens materials, development of optical materials excellent in high refractive index, transparency and the like has been promoted. For example, Patent Document 1 discloses an optical material having such characteristics. Contains 1 to 70% by mass of inorganic fine particles (zirconium oxide, titanium oxide, a mixture thereof, etc.) having a particle size of 1 to 15 nm, contains a chlorine element at a concentration of 100 ppm or less, and contains at least one of an organic acid and an inorganic acid. In addition, there has been proposed an inorganic fine particle dispersion in which the total concentration of the organic acid and the inorganic acid is less than 0.15 times the solid content of the inorganic fine particles.

On the other hand, in organic EL illumination, which is one of the optical devices, it has been studied to provide a high refractive material layer using fine particles made of a metal oxide in order to improve the light extraction rate.
However, metal oxide fine particles have the property of adsorbing moisture, and when a high refractive material layer is formed using fine particles that have absorbed water, outgas is generated due to the moisture adsorbed on the fine particles. It is conceivable that the performance of the organic EL element is adversely affected.

JP 2009-298658 A

Therefore, when a high refractive material layer is provided for organic EL lighting using an inorganic fine particle dispersion as described in Patent Document 1, there is a concern that the performance of the organic EL element may be adversely affected. There has been an increasing demand for an optical material that can provide a high-refractive-index film (high-refractive-index layer) that is highly transparent and generates little outgas.

The present inventors have conducted intensive studies to provide an optical material capable of providing a high-refractive-index film (high-refractive-index layer) having a high refractive index, high transparency, and little outgassing, and an optical composition. It has been found that the object can be achieved by using a dispersion of metal oxide fine particles having a specific average primary particle diameter in the product, and the present invention has been completed.

That is, the present invention
[1] An optical composition comprising metal oxide fine particles, a binder resin, and a solvent,
The water content of the 1-μm-thick film obtained by applying the solution on the substrate and removing the solvent was determined to be 1.0 × 10 ^{−8 to} 3.5 × 10 ⁻⁷ by using a thermal desorption gas analyzer. When measured by raising the temperature from room temperature to 200 ° C. at a rate of 10 ° C. per minute and maintaining the temperature for 30 minutes at a reduced pressure of Pa, it is 3.0 × 10 ⁻⁷ mol / cm ² or less, Optical composition;
[2] The optical composition of [1], obtained using a dispersion of metal oxide fine particles having an average primary particle diameter of 15 to 300 nm;
[3] The optical composition according to [1] or [2], wherein the metal oxide fine particles are at least one selected from the group consisting of zirconium oxide fine particles, titanium oxide fine particles, and barium titanate fine particles;
[4] The binder resin is a resin having a condensed ring structure having a condensed ring structure derived from at least one selected from the group consisting of indene, tetralin, fluorene, xanthene, anthracene, and benzanthracene. The optical composition according to any one of [3];
[5] A thin film or molded article obtained by using the optical composition according to any one of [1] to [4] and having a refractive index of 1.6 to 2.1; and [6]. [5] An optical device including the thin film or the molded body according to [5].

Since the optical composition of the present invention is obtained using a dispersion of metal oxide fine particles having a specific average primary particle diameter, it has a high refractive index and high transparency, and generates outgas derived from moisture. It is suitable for forming a small high-refractive-index film, so that it can be suitably used for optical members and optical devices.
In addition, since the thin film or molded article of the present invention is obtained using the optical composition of the present invention, it has a high refractive index and high transparency, and a high refractive index film (high refractive index layer ).
Furthermore, since the optical device of the present invention includes the thin film or the molded product of the present invention, it has excellent optical characteristics and reliability in applications such as an organic EL element to which the presence of moisture may have an adverse effect.

[1] Optical Composition First, the optical composition of the present invention will be described.
The optical composition of the present invention is an optical composition containing metal oxide fine particles, a binder resin, and a solvent,
The water content of the 1-μm-thick film obtained by applying the solution on the substrate and removing the solvent was determined to be 1.0 × 10 ^{−8 to} 3.5 × 10 ⁻⁷ by using a thermal desorption gas analyzer. When measured by raising the temperature from room temperature to 200 ° C. at a rate of 10 ° C. per minute at a reduced pressure of Pa and holding for 30 minutes, it is characterized by being 3.0 × 10 ⁻⁷ mol / cm ² or less.

(Metal oxide fine particles and dispersion of metal oxide fine particles)
The metal oxide fine particles are selected from the group consisting of zirconium oxide fine particles (hereinafter also referred to as ZrO ₂ fine particles), titanium oxide fine particles (hereinafter also referred to as TiO ₂ fine particles), and barium titanate fine particles (hereinafter also referred to as BaTiO ₃ fine particles). Preferably, at least one selected from them is used.
The shape of the metal oxide fine particles is not particularly limited, and examples thereof include, for example, spheres, oval spheres, powders and granules such as tetrahedrons such as cuboids and cuboids, columns, discs, ellipsoids, and scales. Plate-like, needle-like, etc. are mentioned. The average primary particle diameter of these fine particles is as described above. When the fine particles are not spherical, the average primary particle diameter is the particle diameter of the circumscribed sphere of the metal oxide fine particles.

The optical composition of the present invention is preferably obtained using a dispersion of metal oxide fine particles having an average primary particle size of 15 to 300 nm. By setting the average primary particle diameter of the metal oxide fine particles in the above range, the surface area of the metal oxide fine particles is reduced, and thus the adsorption of moisture can be reduced. It is possible to form a film having a high refractive index and a high transparency while being suppressed.
On the other hand, if the average primary particle size is less than 15 nm, the adsorption of moisture cannot be sufficiently reduced, and if the average primary particle size exceeds 300 nm, the transparency of the film when formed is reduced. May drop significantly.
The average primary particle diameter of the metal oxide fine particles is more preferably from 15 to 100 nm, further preferably from 20 to 50 nm.

The average primary particle diameter of the metal oxide fine particles is a value calculated by statistical processing from an observation image measured by a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM).
Here, the calculation by the statistical processing is performed by calculating using the following formula (A) when a diameter is measured for 1000 particles randomly selected from the SEM image and a histogram of 3 nm section is created. It is. The number average primary particle diameter Dnp obtained by the formula (A) was defined as the average primary particle diameter of the present invention.
Dnp = Σnidi / Σni (A)
Dnp: number average primary particle diameter di: i-th diameter of histogram ni: frequency

The dispersion of metal oxide fine particles having the above average primary particle diameter is prepared by adding metal oxide fine particles having an average primary particle diameter of 15 to 300 nm to a dispersion medium and dispersing the dispersion by means commonly used in this field such as a bead mill. It can be manufactured by

In addition, as a dispersion medium used for dispersing the metal oxide fine particles, the same solvent as described later can be used, and the use amount thereof is not particularly limited as long as the metal oxide fine particles can be dispersed.

The metal oxide fine particles may be surface-treated. The surface treatment refers to a treatment for binding a compound that can react with a hydroxyl group present on the surface of the fine particles, such as a coupling agent. The surface treatment can be performed by dispersing the metal oxide fine particles in a solvent, and then mixing and operating a coupling agent under acidic conditions.
Although it does not specifically limit as a surface treatment agent, A silane coupling agent and a titanium coupling agent are mentioned, for example, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, etc. (Meth) acryloxysilanes; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) Epoxysilanes such as ethyltrimethoxysilane; vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, dimethylvinylmethoxysilane, vinyltrichlorosilane, dimethylvinylchlorosilane; N-2- Aminosilanes such as aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane; N- (vinylbenzyl) -2- Quaternary ammonium salts such as hydrochloride salt of aminoethyl-3-aminopropyltrimethoxysilane; p-styryltrimethoxysilane; phenyltrimethoxysilane; And the like. These surface treatment agents may be used alone or in combination of two or more. Among these surface treatment agents, epoxysilanes and (meth) acrylic compounds having a reactive functional group, are cured together with a resin having a condensed ring structure, and can fix metal oxide fine particles in a thin film or a molded product. Roxysilanes are preferred.

The content of the metal oxide fine particles is not particularly limited, but is preferably 30 to 90% by weight, more preferably 50 to 80% by weight in the optical composition of the present invention.
If the content of the metal oxide fine particles is less than 30% by weight, a film having a high refractive index cannot be formed, and if it exceeds 90% by weight, the particles are aggregated during the film formation, making film formation difficult. In addition, the outgas amount may increase when the optical device is used.

(Binder resin)
The binder resin is not particularly limited, but is preferably a fused ring structure-containing resin having a fused ring structure derived from at least one selected from the group consisting of indene, tetralin, fluorene, xanthene, anthracene and benzanthracene. For example, an epoxy ester resin (E), a polycarboxylic acid resin (G), or the like can be used.
The epoxy ester resin (E) is obtained by reacting an epoxy resin (A) represented by the following general formula (1) with a monobasic carboxylic acid (B), or represented by the following general formula (10). By reacting the alcohol compound (C) with the glycidyl ester compound (D). As the epoxy ester resin (E), a resin having a condensed ring structure derived from xanthene or fluorene is preferable because of its excellent dispersibility and heat resistance.

In the general formula (1), Y _1-4 are each independently a group represented by the following general formula (2) or the following general formula (3), and p _1-4 are each independently from 0 to 4 is an integer.

In the general formula (2), Y _{5 to 6} are each independently a group represented by the general formula (2) or the following general formula (3), and p _{5 to 6} are each independently 0 to 4 Is an integer. When Y _1-4 in the general formula (1) is a group represented by the general formula (2), and Y _5-6 in the general formula (2) is a group represented by the general formula (2) And Y ₁ to Y ₄ in the general formula (1) form an oligomer having a group represented by the general formula (2) as a structural unit.

In the general formulas (1) and (2), Z is at least selected from the group consisting of indene, tetralin, fluorene, xanthene, anthracene, and benzanthracene as shown in the following formulas (4) to (9). A divalent group containing a condensed ring structure derived from one kind, wherein R ₁ to R ₆ are each independently a linear, branched or cyclic alkyl or alkenyl group having 1 to 10 carbon atoms, 1 to 5 alkoxy groups, which may have a substituent phenyl group or a halogen atom, q _{1 to 6} is an integer from 0 to 4 each independently, s _{1 to 2,} the Each is independently an integer from 0 to 10. In the general formulas (1) to (3), R _7-14 are each independently a hydrogen atom or a methyl group, and m _{1 to 8} are each independently an integer of 0 to 10. Here, a plurality of R _1-14 and Y _1-6 may be the same or different. Further, in the general formula (1), the structural formula may be bilaterally symmetric or asymmetric.

In the general formula (10), Z is the same as described above, and R ₁₅ to R ₁₆ each independently represent a linear, branched or cyclic alkyl or alkenyl group having 1 to 10 carbon atoms, 5 is an alkoxy group, a phenyl group which may have a substituent, or a halogen atom, f _{1 to 2} are each independently an integer of 0 to 4, and R _{17 to 18} are each independently A hydrogen atom or a methyl group, m _{9 to 10} are each independently an integer of 0 to 10, and r _{1 to 2} are each independently an integer of 1 to 5. Here, the plurality of R ₁₅ to R ₁₈ may be the same or different. In the general formula (10), the structural formula may be bilaterally symmetric or asymmetric.

The monobasic carboxylic acid (B) is not particularly limited as long as it is a compound having one carboxyl group. For example, (meth) acrylic acid, cyclopropanecarboxylic acid, 2,2,3,3-tetramethyl- 1-cyclopropanecarboxylic acid, cyclopentanecarboxylic acid, 2-cyclopentenylcarboxylic acid, 2-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, cyclohexanecarboxylic acid, 4-propylcyclohexanecarboxylic acid, 4-butylcyclohexanecarboxylic acid, -Pentylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, 4-heptylcyclohexanecarboxylic acid, 4-cyanocyclohexane-1-carboxylic acid, 4-hydroxycyclohexanecarboxylic acid, 1,3,4,5-tetrahydroxycyclohexane- 1- Rubonic acid, 2- (1,2-dihydroxy-4-methylcyclohexyl) propionic acid, shikimic acid, 3-hydroxy-3,3-diphenylpropionic acid, 3- (2-oxocyclohexyl) propionic acid, 3-cyclohexene- 1-carboxylic acid, alkyl hydrogen 4-cyclohexene-1,2-dicarboxylate, cycloheptanecarboxylic acid, norbornenecarboxylic acid, tetracyclododecenecarboxylic acid, 1-adamantanecarboxylic acid, (4-tricyclo [5.2.1 2.0 ^2.6 ] dec-4-yl) acetic acid, p-methylbenzoic acid, p-ethylbenzoic acid, p-octylbenzoic acid, p-decylbenzoic acid, p-dodecylbenzoic acid, p-methoxybenzoic acid, p-ethoxybenzoic acid, p-propoxybenzoic acid, p-butoxybenzoic acid, p-pentyloxybenzoic acid P-hexyloxybenzoic acid, p-fluorobenzoic acid, p-chlorobenzoic acid, p-chloromethylbenzoic acid, pentafluorobenzoic acid, pentachlorobenzoic acid, 4-acetoxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,5-di-t-butyl-4-hydroxybenzoic acid, o-benzoylbenzoic acid, o-nitrobenzoic acid, o- (acetoxybenzoyloxy) benzoic acid, terephthalic acid monomethyl ester, isophthalic acid monomethyl ester, isophthalic acid Monocyclohexyl ester, phenoxyacetic acid, chlorophenoxyacetic acid, phenylthioacetic acid, phenylacetic acid, 2-oxo-3-phenylpropionic acid, o-bromophenylacetic acid, o-iodophenylacetic acid, methoxyphenylacetic acid, 6-phenylhexanoic acid, biphenyl Carboxylic acid, α- Phthoic acid, β-naphthoic acid, anthracene carboxylic acid, phenanthrene carboxylic acid, anthraquinone-2-carboxylic acid, indane carboxylic acid, 1,4-dioxo-1,4-dihydronaphthalene-2-carboxylic acid, 3,3-diphenyl Examples include propionic acid, nicotinic acid, isonicotinic acid, cinnamic acid, 3-methoxycinnamic acid, 4-methoxycinnamic acid, and quinolinecarboxylic acid. These may be used alone or in combination of two or more. Particularly preferred monobasic carboxylic acids (B) are those containing an unsaturated group capable of introducing a radiation-polymerizable functional group, and for example, (meth) acrylic acid is preferred. Here, the radiation polymerizable functional group refers to a functional group having a property of causing a polymerization reaction by various radiations. “Radiation” includes visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, molecular beams, γ-rays, synchrotron radiation, proton beam rays, and the like.

Although it does not specifically limit as a glycidyl ester compound (D), For example, glycidyl (meth) acrylate, glycidyl acetate, glycidyl butyrate, glycidyl benzoate, glycidyl p-ethylbenzoate, glycidyl (tere) phthalate, etc. are mentioned. . These may be used alone or in combination of two or more. Of these, monobasic glycidyl carboxylate is particularly preferred, and those containing an unsaturated group capable of introducing a radiation-polymerizable functional group are particularly preferable. For example, glycidyl (meth) acrylate is preferred.

Reaction of the epoxy resin (A) represented by the general formula (1) with the monobasic carboxylic acid (B), and the alcohol compound (C) and the glycidyl ester compound (D) represented by the general formula (10) Are carried out in a temperature range of 50 to 120 ° C. for 5 to 30 hours using a suitable solvent as required. Examples of the solvent include alkylene such as methyl cellosolve acetate, propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and 3-methoxybutyl-1-acetate. Monoalkyl ether acetates; alkylene monoalkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol dibutyl ether; ketones such as methyl ethyl ketone and methyl amyl ketone; dimethyl succinate, diethyl succinate, diethyl adipate, malonic acid Diethyl, oxalic acid Esters such as butyl and the like. Of these, propylene glycol monomethyl ether acetate and 3-methoxybutyl-1-acetate are preferred. Further, a catalyst and a polymerization inhibitor can be used as needed. Examples of the catalyst include phosphonium salts, quaternary ammonium salts, phosphine compounds, tertiary amine compounds, imidazole compounds, and the like. The amount of the catalyst is not particularly limited, but is not particularly limited. It is preferably from 0.01 to 10% by weight. Examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, 4-methylquinoline, phenothiazine, 2,6-diisobutylphenol, 2,6-di-tert-butyl-4-methylphenol and the like. The amount is usually not more than 5% by weight of the whole reaction product.

The polycarboxylic acid resin (G) can be obtained by reacting the epoxy ester resin (E) with a polybasic carboxylic acid or its anhydride (F).

The polybasic carboxylic acid or its anhydride (F) is not particularly limited as long as it is a carboxylic acid having a plurality of carboxyl groups such as dicarboxylic acid and tetracarboxylic acid or its anhydride, and examples thereof include maleic acid and succinic acid. Dicarboxylic acids such as, itaconic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic acid, methyltetrahydrophthalic acid, glutaric acid and anhydrides thereof; Acids or anhydrides thereof: tetracarboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid and diphenylethertetracarboxylic acid, and dianhydrides thereof.

Examples of the polycarboxylic acid resin (G) include a resin represented by the following general formula (11) or the following general formula (12).

In the general formulas (11) and (12), Z is a divalent group containing a condensed ring structure derived from at least one selected from the group consisting of indene, tetralin, fluorene, xanthene, anthracene, and benzanthracene. A ₁ and A ₃ are residues of tetracarboxylic dianhydride, and A ₂ and A ₄ are residues of dicarboxylic anhydride. U and u ₂ are average values, and are 0 to 130.

In the general formulas (11) and (12), Z is preferably a divalent group containing a condensed ring structure derived from xanthene or fluorene. This is because the polyvalent carboxylic acid resin (G) is advantageous in that the refractive index is high and the difference in refractive index from the metal oxide fine particles can be reduced.

The polycarboxylic acid resin (G) is obtained by reacting the epoxy ester resin (E) with the polybasic carboxylic acid or its anhydride (F). In this reaction, a polyhydric alcohol can be coexistent to improve the heat resistance and heat yellowing resistance of the obtained resin.

The polyhydric alcohol is not particularly limited, but for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol , Neopentyl glycol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,6-nonanediol, and fats such as 1,9-nonanediol Aliphatic diols, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, alicyclic diols such as hydrogenated bisphenol A, aromatic diols such as ethylene oxide and propylene oxide adducts of bisphenol A, glycerin, trimethylolpropane, Methylolethane, ditrimethy Rupuropan, pentaerythritol, sorbitol, trihydric or higher alcohols such as dipentaerythritol and the like. These may be used alone or in combination of two or more.

In this reaction, the order of addition of the epoxy ester resin (E), the polyhydric alcohol, and the polybasic carboxylic acid or its anhydride (F) is not particularly limited. For example, these may be mixed and reacted simultaneously, or the epoxy ester resin (E) and the polyhydric alcohol may be mixed, and then the polybasic carboxylic acid or its anhydride (F) may be added and mixed. Is also good. Further, a polybasic carboxylic acid may be further added to these reaction products to cause a reaction.

By appropriately selecting the type of the polybasic carboxylic acid or its anhydride (F), a polyhydric carboxylic acid resin (Ga) having various condensed ring structures having different structures and a polyhydric alcohol were reacted. A polycarboxylic acid resin (Gb) can be produced. Specifically, for example, the first to sixth polyvalents shown in the following (Gai) to (Ga-iii), (Gbi) to (Gb-iii) Carboxylic acid resins are prepared, but these are exemplary.

(Gai) First polycarboxylic acid resin: a resin obtained by mixing and reacting an epoxy ester resin (E) with one kind of polybasic carboxylic acid or its anhydride (F) (G-a-ii) a second polycarboxylic acid resin: a mixture of an epoxy ester resin (E) and two or more polybasic carboxylic acids or anhydrides (F) thereof (for example, a dicarboxylic anhydride) (G-a-iii) a third polycarboxylic acid resin: an epoxy ester resin (E) and a tetracarboxylic acid resin. A resin obtained by reacting an acid or a dianhydride thereof and reacting the obtained reaction product with a dicarboxylic acid or an anhydride thereof.

(G-bi) Fourth polycarboxylic acid resin: an epoxy ester resin (E), a polyhydric alcohol, and one kind of polybasic carboxylic acid or its anhydride (F) are mixed and reacted. (G-b-ii) Fifth polycarboxylic acid resin: epoxy ester resin (E), polyhydric alcohol, and two or more kinds of polybasic carboxylic acids or anhydrides thereof (F-b-ii). ) (E.g., a mixture of dicarboxylic anhydride and tetracarboxylic dianhydride), and a resin obtained by reacting the mixture; and (G-b-iii) a sixth polycarboxylic acid resin: A resin obtained by reacting an epoxy ester resin (E), a polyhydric alcohol, and a tetracarboxylic acid or a dianhydride thereof, and further reacting the obtained reaction product with a dicarboxylic acid or an anhydride thereof.

The polyvalent carboxylic acid resin (Ga) or (Gb) thus obtained having various condensed ring structures having different structures is used depending on the intended use.

In addition, "polybasic carboxylic acid or its anhydride (F)" means "at least one of a specific polybasic carboxylic acid and its corresponding anhydride". If the acid is phthalic acid, it refers to at least one of phthalic acid and phthalic anhydride. Further, “a mixture of two or more kinds of polybasic carboxylic acids or anhydrides (F) thereof” means that at least two kinds of polybasic carboxylic acids or anhydrides thereof are present at the same time. Therefore, in the methods (G-a-ii) and (G-b-ii), at least two kinds of polybasic carboxylic acids or their anhydrides (F) participate in the reaction.

In any of the above methods, the polycarboxylic acid resin (G) is obtained by converting the epoxy ester resin (E), the polyhydric alcohol, the polybasic carboxylic acid or its anhydride (F) by the method (order) exemplified above. It is produced by dissolving (suspending) in a solvent and reacting by heating. As the solvent, for example, ethyl cellosolve acetate, cellosolve solvents such as butyl cellosolve acetate, propylene glycol monomethyl ether acetate, ester solvents of alkylene glycol monoalkyl ethers such as 3-methoxybutyl acetate and acetic acid, methyl ethyl ketone, methyl isobutyl ketone And ketone solvents such as cyclohexanone. Further, a catalyst can be added as needed. Examples of the catalyst include phosphonium salts, quaternary ammonium salts, phosphine compounds, tertiary amine compounds, imidazole compounds, and the amount thereof is not particularly limited. It is preferably from 10 to 10% by weight.

The reaction temperature of the above reaction is not particularly limited, but is preferably from 50 to 130 ° C, more preferably from 70 to 120 ° C. When the reaction temperature is lower than 50 ° C., the reaction does not proceed smoothly, and unreacted polybasic carboxylic acid or its anhydride (F) may remain. On the other hand, when the temperature exceeds 130 ° C., condensation of a carboxyl group and a hydroxyl group partially occurs, and the molecular weight may increase rapidly.

When a polyhydric alcohol is used in the production of the polyhydric carboxylic acid resin (G), the molar ratio of the hydroxyl group of the epoxy ester resin (E) to the hydroxyl group of the polyhydric alcohol (hydroxyl / polyhydric of the epoxy ester resin (E)) Although the hydroxyl group of the alcohol is not particularly limited, it is preferably from 99/1 to 50/50, and more preferably from 95/5 to 60/40. When the molar ratio of the hydroxyl group of the polyhydric alcohol exceeds 50, the molecular weight of the polyvalent carboxylic acid resin (G) sharply increases, which may cause gelation. If the molar ratio is less than 1, the heat resistance and the heat discoloration resistance tend to be hardly improved.

The blending amount of the polybasic carboxylic acid or its anhydride (F) is not particularly limited, but the hydroxyl group of the epoxy ester resin (E) (in the case of using a polyhydric alcohol, the total number of hydroxyl groups of the polyhydric alcohol) is 1 It is preferably 0.1 to 1 equivalent, more preferably 0.4 to 1 equivalent in terms of an acid anhydride group, based on the equivalent (mol). If the compounding amount is less than 0.1 equivalent, the molecular weight of the polyvalent carboxylic acid resin (G) will not be sufficiently high, and the heat resistance of the cured product of the optical composition containing the polyvalent carboxylic acid resin (G) will be insufficient. Or the optical composition may remain on the substrate after development. On the other hand, when the compounding amount exceeds 1 equivalent, unreacted polybasic carboxylic acid or its anhydride (F) remains, the molecular weight of the polyvalent carboxylic acid resin (G) decreases, and The developability of the optical composition containing the resin (G) may be poor. The term "acid anhydride group conversion" refers to the amount when all the carboxyl groups and acid anhydride groups contained in the polybasic carboxylic acid or its anhydride (F) used are converted into acid anhydride groups.

In producing the second, third, fifth, and sixth polycarboxylic acid resins (G), two or more kinds of polybasic carboxylic acids or anhydrides (F) thereof are used. Generally, dicarboxylic anhydride and tetracarboxylic dianhydride are used. The ratio of dicarboxylic anhydride to tetracarboxylic dianhydride (dicarboxylic anhydride / tetracarboxylic dianhydride) is preferably from 1/99 to 90/10, and preferably from 5/95 to 80 / molar. / 20 is more preferable. If the ratio of the dicarboxylic anhydride is less than 1, the viscosity of the resin increases, and the workability may be reduced. In addition, since the molecular weight of the polyvalent carboxylic acid resin (G) is too large, when a coating film is formed on a substrate using an optical composition containing the polyvalent carboxylic acid resin (G) and exposure is performed. In addition, the exposed portion is less likely to be dissolved in the developer, and the desired pattern tends to be hardly obtained. On the other hand, if the ratio of the dicarboxylic anhydride exceeds 90, the molecular weight of the polyvalent carboxylic acid resin (G) becomes too small. When a coating film is formed, problems such as sticking remaining in the coating film after prebaking are likely to occur.

In the optical composition of the present invention, the polycarboxylic acid resin (G) preferably contains a radiation-polymerizable functional group, and specifically contains an unsaturated group such as a (meth) acryloyl group. Is preferred. When the polycarboxylic acid resin (G) is a resin containing a radiation-polymerizable functional group, the optical composition of the present invention has photocurability, so that it is used as the photosensitive composite resin composition (H). Can be done. Here, the term “photosensitivity” refers to the property of causing a chemical reaction by various types of radiation, and such radiations include visible rays, ultraviolet rays, electron beams, X-rays, α-rays, and β-rays in order of wavelength. , And γ-rays. Of these, ultraviolet rays are the most preferable radiation in practical terms from the viewpoint of economy and efficiency. Ultraviolet light oscillated from a lamp such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, and a xenon lamp can be suitably used as the ultraviolet light. Radiation having a shorter wavelength than ultraviolet light has high chemical reactivity and is theoretically superior to ultraviolet light, but ultraviolet light is practical from the viewpoint of economy.

The content of the binder resin is not particularly limited, but is preferably 10 to 100 parts by weight, and more preferably 15 to 50 parts by weight, based on 100 parts by weight of the metal oxide fine particles in the optical composition of the present invention. Is more preferable.
If the content of the binder resin is less than 10 parts by weight, fine particles may aggregate during film formation and cracks may be formed in the film, and if it exceeds 100 parts by weight, the refractive index may not be sufficiently high. .

In addition, the optical composition of the present invention uses the above-mentioned binder resin as a binder resin.When a cured product is obtained, these binder resins exhibit a relatively high refractive index. As a result, the use amount of the metal oxide fine particles can be reduced, so that there is an advantage that the generation of the outgas amount can be reduced.
Further, in the optical composition of the present invention, since the binder resin also acts as a dispersant for the metal oxide fine particles, the dispersant described below is not used, or even if used, the amount of the dispersant can be reduced. Therefore, there is an advantage that inconveniences such as a decrease in the refractive index of an optical device can be avoided.

(solvent)
The solvent is not particularly limited and includes, for example, alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; ethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, and ethylene glycol monoethyl ether. Ethers; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; diethylene glycol dialkyl ethers such as diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether; diethylene glycol monomethyl ether, diethylene glycol Diethylene glycol monoalkyl ethers such as noethyl ether and diethylene glycol monobutyl ether; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate and ethylene glycol mono Alkylene glycol monoalkyl ether acetates such as butyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate and 3-methoxybutyl-1-acetate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone, methyl amyl ketone, cyclo Ketones such as xanone, 4-hydroxy-4-methyl-2-pentanone; ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate , Ethyl hydroxyacetate, methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl acetate, butyl acetate, lactic acid Esters such as methyl, ethyl lactate, dimethyl succinate, diethyl succinate, diethyl adipate, diethyl malonate, dibutyl oxalate and the like can be mentioned. Of these, ethylene glycol ethers, alkylene glycol monoalkyl ether acetates, diethylene glycol dialkyl ethers, ketones and esters are preferred, and ethyl 3-ethoxypropionate, ethyl lactate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl. Ether acetate and methyl amyl ketone are more preferably used. These solvents may be used alone or in combination of two or more.

The content of the solvent is not particularly limited, but is preferably from 5 to 95% by weight, more preferably from 30 to 90% by weight, in the optical composition of the present invention.
If the content of the solvent is less than 5% by weight, it may be difficult to maintain a dispersed state, and if it exceeds 95% by weight, it may be difficult to form a thick film.

The optical composition of the present invention may contain optional components such as a dispersant and a curing agent, as required, in addition to the metal oxide fine particles, the binder resin, and the solvent.

(Dispersant)
The dispersant is not particularly limited, and examples thereof include a polyacrylic acid-based dispersant, a polycarboxylic acid-based dispersant, a phosphoric acid-based dispersant, and a silicon-based dispersant. These dispersants may be used alone or in combination of two or more.
When the optical composition of the present invention contains a dispersant, the content is preferably 10 parts by weight or less, more preferably 5 parts by weight or less based on 100 parts by weight of the metal oxide fine particles.

(Curing agent)
The curing agent is not particularly limited, and examples thereof include α-aminoalkylphenone-based photopolymerization initiators. These curing agents may be used alone or in combination of two or more.
When the optical composition of the present invention contains a curing agent, the content is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The optical composition of the present invention was applied on a substrate, and the water content of a 1 μm-thick film obtained by removing the solvent was adjusted to 1.0 × 10 ⁻ by using a thermal desorption gas analyzer. 3.0 × 10 ⁻⁷ mol / cm ² when measured by raising the temperature from room temperature to 200 ° C. at a rate of 10 ° C. per minute at a reduced pressure of ^{8 to} 3.5 × 10 ⁻⁷ Pa and holding for 30 minutes. It is as follows.
When the water content is 3.0 × 10 ⁻⁷ mol / cm ² or less, the generation of outgas due to the presence of water remains at a low level, and there is a concern that the generation of this outgas may cause a decrease in performance. It can be suitably used for optical members and optical devices.
In addition, in this specification, "removing a solvent" means performing a heat treatment at 80 to 200 ° C. for 1 minute to 1 hour after applying the optical composition to a substrate.
The water content of the optical composition after film formation can be controlled by appropriately selecting the average primary particle diameter, the composition, and the like of the metal oxide fine particles to be used.

The refractive index of the thin film or molded product obtained by using the optical composition of the present invention is not particularly limited, but is preferably from 1.6 to 2.1. The refractive index of the thin film or molded article can be controlled by appropriately selecting the average primary particle diameter of the metal oxide fine particles contained in the optical composition of the present invention, the amount of the binder resin, and the like.

The method for producing the optical composition is not particularly limited, and the components may be added and mixed at the same time, or the operation of adding and mixing other components to the solvent may be sequentially performed. Further, for example, when two or more kinds of metal oxide fine particles are contained as the metal oxide fine particles, a dispersion of each metal oxide fine particle may be dispersed simultaneously or separately in a solvent.

[2] Thin Film, Molded Article and Optical Device Since the above-mentioned optical composition can be a high refractive index material with little outgassing, it is extremely suitable for optical devices in the form of optical members, thin films and molded articles. Can be used.
In particular, the optical composition of the present invention may be deteriorated in performance due to generation of outgas, and is suitably used for an optical device that requires a high refractive index and high transparency.
Specific examples of such optical devices include, for example, organic EL lighting, organic EL displays, touch panels, liquid crystal displays, CMOS image sensors, and the like.

Hereinafter, the optical device of the present invention will be further described with an example in which the optical device is an organic EL illumination.
The organic EL lighting includes an organic EL element layer, a transparent electrode layer and a glass layer laminated thereon. Then, the light extraction efficiency is reduced due to a large difference between the refractive index (1.9 to 2.0) of the organic EL element layer and the transparent electrode layer and the refractive index (about 1.5) of the glass layer.
Therefore, in the organic EL lighting according to the optical device of the present invention, a high refractive index film is provided between the transparent electrode layer and the glass layer, and the high refractive index film is formed of the optical composition of the present invention. It is formed using. Therefore, the organic EL lighting is excellent in light extraction efficiency.
The performance of the organic EL element is adversely affected by the moisture, but the high refractive index film generates less outgas, so that the above-mentioned disadvantage can be avoided.
In the organic EL lighting, the refractive index of the high refractive index film is preferably close to the refractive index of the organic EL element layer and the transparent electrode layer.
The optical device is not limited to the organic EL illumination, but may be any optical device provided with a high refractive index film.

The high refractive index film in the optical device can be formed by the following method.
That is, it can be formed by applying the optical composition of the present invention by various conventionally known methods, and then performing a heating treatment (drying or curing treatment) or irradiation with ionizing radiation according to the composition.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to only these examples.

1. Raw material used 1-1. Metal oxide fine particles zirconium oxide (UEP-100, manufactured by Daiichi Kagaku Kagaku Kogyo Co., Ltd., average primary particle diameter 10 nm)
Zirconium oxide (UEP-50, manufactured by Daiichi Kagaku Kagaku Kogyo Co., Ltd., average primary particle diameter 20 nm)
Zirconium oxide (UEP, average primary particle diameter 40 nm, manufactured by Daiichi Kagaku Kagaku Kogyo KK)
Titanium oxide (manufactured by Showa Denko KK, Super Titania F-6, average primary particle diameter 15 nm)

1-2. Solvent cyclohexanone (Sinopec)
Propylene glycol monomethyl ether (PGME, manufactured by Japan Emulsifier Co., Ltd.)

1-3. Dispersant Polymeric dispersant (BYK-118, manufactured by Big Chemie Japan, 100% active ingredient)

1-4. Curing agent 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (IRGACURE907, manufactured by BASF Japan Ltd.)

2. Synthesis of Resin Containing Condensed Ring Structure (Binder Resin) (Production Example 1) Synthesis of Resin A Containing Condensed Ring Structure In a 300 ml four-necked flask, 115 g of bisphenol full orange glycidyl ether (Oxol PG, manufactured by Osaka Gas Chemical Co., Ltd.) ( Epoxy equivalent 270 g / eq), 600 mg of triethylbenzylammonium chloride as a catalyst, 30 mg of 2,6-diisobutylphenol as a polymerization inhibitor, and 36 g of acrylic acid were charged, and 90 to 100 ° C. while blowing air at a rate of 10 mL / min. And dissolved by heating. Next, this was gradually heated to 120 ° C. Although the solution became transparent and viscous, stirring was continued as it was. During this time, the acid value was measured, and heating and stirring were continued until the acid value became less than 1.0 mgKOH / g, to obtain a pale yellow transparent solid epoxy ester resin having a condensed ring structure. It took 15 hours for the acid value to reach the target. 65 g of propylene glycol monomethyl ether acetate (manufactured by Nippon Emulsifier Co., Ltd., PGMEA) was added to and dissolved in the condensed ring structure-containing epoxy ester resin, and then 15 g of pyromellitic anhydride (PMDA) and tetrahydrophthalic anhydride (THPA) 7 were added. And 0.1 g of tetraethylammonium bromide. The mixture was gradually heated and reacted at 110 to 115 ° C. for 14 hours. In this way, a PGMEA solution of the fused ring structure-containing resin A was obtained. The disappearance of the acid anhydride was confirmed by an IR spectrum. The resin A having a condensed ring structure corresponds to the polyvalent carboxylic acid resin (G-a-ii).

3. Optical composition (Examples 1 to 4, Comparative example 1)
A solvent, a resin having a condensed ring structure (binder resin), and a dispersant are mixed in the amounts shown in Table 1, and then, metal oxide fine particles are added and mixed using a media-type dispersing machine (bead mill) to form a metal oxide. The fine particles were dispersed, and a curing agent was further mixed to obtain an optical composition. Using the obtained optical composition, the average particle diameter after dispersion and the water content of the coating film were calculated by the method described below. Table 1 shows the results. In Table 1, the compounding amounts of the solvent, the dispersant and the binder resin indicate parts by weight based on 100 parts by weight of the metal oxide fine particles, and the compounding amounts of the curing agent indicate parts by weight based on 100 parts by weight of the binder resin.

4. Method for Forming Thin Film The optical composition obtained in each of Examples and Comparative Examples was applied on a glass substrate using a spinner, and then prebaked on a hot plate at 90 ° C. for 2 minutes to obtain a coating having a thickness of about 1 μm. A film was formed. The surface of the coating film is irradiated with ultraviolet light having a light intensity of 9.5 mW / cm ² at a wavelength of 405 nm using a high-pressure mercury lamp of 250 W under a nitrogen atmosphere so that the exposure amount becomes 1000 mJ / cm ^2. After curing, a thin film was obtained. The resulting thin film was evaluated for total light transmittance, haze value, and refractive index by the methods described below. Table 1 shows the results.

5. Evaluation method 5-1. Average particle size after dispersion About the optical composition obtained in each Example and Comparative Example, Z-average was performed based on the scattering intensity distribution measured by the dynamic light scattering method using Zetasizer Nano ZS manufactured by Malvern. The particle size was calculated.

5-2. The total light transmittance was measured using a haze meter HZ-2 manufactured by Suga Test Instruments Co., Ltd.

5-3. Haze value was measured using a haze meter HZ-2 manufactured by Suga Test Instruments Co., Ltd.

5-4. The refractive index at a wavelength of 633 nm was measured using a refractive index light interference type film quality measuring device.

5-5. Water content After applying the optical compositions obtained in the respective Examples and Comparative Examples on a silicon substrate using a spinner, prebaking was performed on a hot plate at 90 ° C. for 2 minutes to form a coating film having a thickness of about 1 μm. Formed. The surface of the coating film is irradiated with ultraviolet light having a light intensity of 9.5 mW / cm ² at a wavelength of 405 nm using a high-pressure mercury lamp of 250 W under a nitrogen atmosphere so that the exposure amount becomes 1000 mJ / cm ^2. After curing, a thin film was obtained.
Next, the prepared coating film was put together with the substrate into a thermal desorption gas analyzer (manufactured by Denshi Kagaku Co., Ltd., EMD-WA1000S / w), and the inside of the apparatus was decompressed at 1.0 × 10 ⁻⁸ -3 0.5 × 10 ⁻⁷ Pa.
Thereafter, the inside of the apparatus was heated from room temperature to 200 ° C. at a rate of 10 ° C./min, held for 30 minutes, and the amount of water evaporated from the coating film was measured.
The results are shown in Table 1.

As shown in Table 1, according to the optical composition of the present invention, it was clarified that a high refractive index film having high refractive index, high transparency, and little outgassing can be provided.

Claims (3)

An optical composition comprising 15 to 50 parts by weight of a binder resin and 100 parts by weight of zirconium oxide fine particles having an average primary particle diameter of 15 to 300 nm, and a solvent,
The binder resin comprises an epoxy ester resin or a polycarboxylic acid resin having a condensed ring structure derived from at least one selected from the group consisting of indene, tetralin, fluorene, xanthene, anthracene and benzanthracene,
The water content of the 1 μm-thick film obtained by applying the film on the substrate and removing the solvent by heat treatment at 80 to 200 ° C. for 1 minute to 1 hour was measured using a thermal desorption gas analyzer. When measured by raising the temperature from room temperature to 200 ° C. at a rate of 10 ° C. per minute at a reduced pressure of 0.0 × 10 ^{−8 to} 3.5 × 10 ⁻⁷ Pa and holding for 30 minutes, 3.0 × 10 ^{− An} optical composition having a molecular weight of ⁷ mol / cm ² or less and a refractive index of 1.6 to 2.1. A thin film or molded article obtained by using the optical composition according to claim 1, having a refractive index of 1.6 to 2.1. An optical device comprising the thin film or the molded body according to claim 2.