JP2008202008A - Sealing resin composition for optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing resin composition for an optical element which exhibits high transparency, excellent resistance to an ultraviolet ray and high refractive index, in combination. <P>SOLUTION: This sealing resin composition for the optical element comprises (i) a ladder or random structure of a silsesquioxane derivative and (ii) an inorganic fine particle as a main component, and is in the state of the B-stage. The silsesquioxane derivative is obtained by co-hydrolyzing and co-condensating a trialkoxysilane (A) having a 1-20C alkyl group or a phenyl group which may have a 1-8C hydrocarbon group, and a trialkoxysilane (B) having a substituent containing a reactive cyclic ether group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing resin composition for optical elements having both transparency, ultraviolet resistance, and a higher refractive index, and an optical element sealed with the composition.

  In recent years, high-intensity LEDs using a GaN-based compound semiconductor such as InGaN having an emission wavelength of 350 to 490 nm have been put into practical use. Furthermore, a white LED can be obtained by combining with a phosphor. These have been actively used as backlights for display devices such as liquid crystal televisions and mobile phones, and demand for general lighting is increasing.

  Conventionally, an epoxy resin excellent in processability has been frequently used as an LED sealing resin (see, for example, Patent Documents 1 and 2). While these have high adhesiveness and heat resistance, they have low resistance to light in the blue to ultraviolet region, and have the property of easily yellowing. Since yellowing causes a decrease in the luminance of the LED, it has become difficult to adapt to an LED sealant that is increasing in luminance.

  On the other hand, since the siloxane skeleton has excellent ultraviolet resistance, a cage-type silsesquioxane resin or a rubbery silicone resin is used as an LED sealing resin (see, for example, Patent Documents 3 and 4). However, in general, a silicon-based resin has a refractive index of about 1.40 to 1.55 and does not necessarily have a sufficiently high refractive index, which causes a reduction in light extraction efficiency. Furthermore, many silicon-based resins have low hardness, and there is a problem that the surface is scratched or dust easily adheres. Further, these are usually liquid and cannot be used for transfer molding for mass production.

That is, a method using a low-pressure transfer molding machine is known as a method for efficiently and continuously sealing LEDs. This method uses a solid LED sealing material in a B-stage (semi-cured state), and can seal LEDs in large quantities compared to casting using a liquid LED sealing material. is there. The B stage is a stage in the reaction of the thermosetting resin, which follows the A stage where the resin remains soluble in the solvent, and before the C stage where the resin is completely cured. And characterized as a viscosity increasing process. That is, it means that the reaction proceeds moderately and is in a semi-cured state.
JP-A-9-208805 JP 2002-302533 A JP 2006-299150 A JP 2002-374007 A

  In view of the above-mentioned present situation, an object of the present invention is to provide a sealing resin composition for optical elements that can be applied to transfer molding, has excellent transparency and ultraviolet resistance, and also has a high refractive index. .

  As a result of intensive studies to solve the above-mentioned problems, the inventor has a ladder-type or random-type silsesquioxane derivative (i) and inorganic fine particles (b) containing a specific type of side chain as a main component, B It was found that the staged encapsulating resin composition had excellent light transmittance, ultraviolet resistance and high refractive index, and the present invention was completed based on this finding. That is, the present invention provides the following general formula (1):

(In the formula, each of a plurality of R's independently represents a methyl group or an ethyl group, and R1 represents an alkyl group having 1 to 20 carbon atoms, or has a hydrocarbon group having 1 to 8 carbon atoms. A trialkoxysilane (A) represented by:
The following general formula (2):

(Wherein a plurality of R's independently represent a methyl group or an ethyl group, and R2 represents a substituent containing a reactive cyclic ether group) and a trialkoxysilane (B) represented by A B-staged encapsulating resin composition for optical elements, which is mainly composed of a silsesquioxane derivative (A) having a ladder type structure or a random type structure obtained by decomposition and cocondensation and inorganic fine particles (B). is there.
The present invention is also an optical element that is sealed with the sealing resin composition.

(1) The sealing resin composition of this invention is excellent in ultraviolet-ray resistance by the above-mentioned structure.
(2) The sealing resin composition of the present invention has a high refractive index and can satisfy the required performance required for the high-luminance optical element sealing agent at a sufficient level by the above-described configuration.
(3) The sealing resin composition of the present invention can be transfer molded by the above-described configuration.

  In the trialkoxysilane (A) in the present invention, in the general formula (1), R1 represents an alkyl group having 1 to 20 carbon atoms, or has a hydrocarbon group having 1 to 8 carbon atoms. Represents an optionally substituted phenyl group.

  Examples of the alkyl group having 1 to 20 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s- or t-butyl, pentyl, isopentyl, neopentyl, octyl, isooctyl, dodecyl, tetradecyl and the like. Can do. Among these, a C1-C12 alkyl group is preferable and a C2-C8 alkyl group is more preferable.

  Examples of the phenyl group which may have a hydrocarbon group having 1 to 8 carbon atoms include, for example, phenyl, tolyl, xylyl, cumenyl, methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, heptyl And a phenyl group having a substituent such as octyl.

  In the trialkoxysilane (A), R1 in the general formula (1) is an alkyl group having 2 to 8 carbon atoms or a phenyl group optionally having a hydrocarbon group having 1 to 2 carbon atoms. preferable.

  Specific examples of the trialkoxysilane (A) include, for example, R is a methyl group, an ethyl group, two methyl groups and one ethyl group, or one methyl group. In particular, there are two ethyl groups, and for each of them, R1 is ethyl, isobutyl, isooctyl, phenyl or the like.

  In the present invention, as the trialkoxysilane (A), one or two or more of the above-mentioned groups can be used in combination.

  In the trialkoxysilane (B) in the present invention, in the general formula (2), R2 represents a substituent containing a reactive cyclic ether group.

  Examples of the reactive cyclic ether group include an epoxy group, a 3,4-epoxycyclohexyl group, an oxetanyl group, tetrahydrofuran, and tetrahydropyran. Among these, an epoxy group, a 3,4-epoxycyclohexyl group, and an oxetanyl group are preferable, and an epoxy group and a 3,4-epoxycyclohexyl group are more preferable.

  The substituent containing the reactive cyclic ether group is not particularly limited, and includes, for example, the reactive cyclic ether group (for example, an epoxy group, a 3,4-epoxycyclohexyl group, an oxetanyl group, etc.) and an ether. C1-10 hydrocarbon group which may have a bond, silyloxy group containing the above reactive cyclic ether group (for example, epoxy group, 3,4-epoxycyclohexyl group, oxetanyl group, etc.) be able to.

  Specific examples of the trialkoxysilane (B) include, for example, R is a methyl group, an ethyl group, two methyl groups and one ethyl group, or one methyl group. Each of which has two ethyl groups, and for each of them, R1 contains an epoxy group, a 3,4-epoxycyclohexyl group or an oxetanyl group, and may have an ether bond. Examples thereof include a hydrogen group or a silyloxy group containing an epoxy group, a 3,4-epoxycyclohexyl group, or an oxetanyl group.

  In the present invention, as the trialkoxysilane (B), one or two or more of the above-mentioned groups can be used in combination.

  The silsesquioxane derivative in the present invention has a ladder type structure or a random type structure obtained by cohydrolyzing and cocondensing the trialkoxysilane (A) and the trialkoxysilane (B). The silsesquioxane derivative in the present invention may be a ladder structure only, a random structure only, or a mixture of a ladder structure and a random structure.

  It is known that silsesquioxane derivatives can be obtained in a ladder type or a random type structure depending on the conditions of co-hydrolysis and co-condensation of trialkoxysilane, and as a method for producing a ladder type or random type structure Can be produced by, for example, the method described in the examples of the present specification or the method described in JP-A-6-306173.

  The ladder-type silsesquioxane derivative has, for example, the following structure.

  In the above formula, a plurality of X are the same or different and represent a reactive cyclic ether group, and a plurality of Y are the same or different and represent an alkyl group having 1 to 12 carbon atoms, or a hydrocarbon group having 1 to 8 carbon atoms. Represents a phenyl group which may have

  The mixing molar ratio of the trialkoxysilane (A) and the trialkoxysilane (B) is preferably 10:90 to 90:10, and more preferably 40:60 to 80:20. If the molar ratio of trialkoxysilane (A) is less than 10, the crosslink density after curing increases, and the mechanical strength may decrease.

  It is preferable that the weight average molecular weights of the silsesquioxane derivative in this invention are 1500-10000, More preferably, it is 2000-8000. If the weight average molecular weight is less than 1500, the heat resistance may not be sufficient, and if it exceeds 10,000, the viscosity may be high and it may be difficult to take out.

  The silsesquioxane derivative is used in combination with an alkoxysilane other than the trialkoxysilane (A) and trialkoxysilane (B) (for example, mono, di, or trialkoxysilane) as long as the object of the present invention is not impaired. For example, it is not excluded that about 0.1 to 5 mol%.

  In the composition of the present invention, the above-mentioned ladder-type or random-type silsesquioxane derivative is the main component. However, the silsesquioxane derivative having a cage-type structure is used as long as the object of the present invention is not impaired. It does not exclude the inclusion.

The inorganic fine particles (b) in the present invention are used for controlling the refractive index of the sealant. As the compound, ceramics is preferable from the viewpoint of giving a high refractive index. Examples of the ceramics include minerals (gypsum, quartz, calcite, etc.), metal oxides, metal composite oxides (complex oxides containing at least one of titanium and zirconium atoms, such as TiMOx (M is Zr, Fe, Si, Sn, Sb, W, Ce, etc.)), nitrides (BN, AiN, Si ₃ N ₄ etc.), carbonates (SrCO ₃ , BaCO ₃ etc.), carbides (SiC, TiC, B ₄ C, WC, etc.), sulfides (CdS, MoS ₂ , rare earth sulfides, etc.), phosphorus oxides (calcium phosphate, bismuth phosphate, etc.), borides (LaB ₆ , TiB ₂ , ZrB ₂ etc.), etc. Can do. Among them, metal oxides such as zinc oxide, titanium oxide, zirconium oxide, tin oxide, cerium oxide, calcium oxide, aluminum oxide, silicon oxide, magnesium oxide, antimony oxide, yttrium oxide, holmium oxide; among titanium and zirconium atoms A composite oxide containing at least one kind is preferable in terms of excellent transparency in the visible light region, and is composed of (a) titanium oxide, (b) zirconium oxide, and (c) a composite oxide containing titanium and / or zirconium atoms. More preferably, it is at least one selected from the group.

The form of the inorganic fine particles is not particularly limited, and may be fine particle powder, paste or sol, for example. A sol is preferable.

Generally the average primary particle diameter of the said inorganic fine particle (b) should just be less than the wavelength of light, for example, 100 nm or less is preferable, More preferably, it is a particle diameter of 30 nm or less. Specific examples of the inorganic fine particles include “QUEEN TITANIC” (trade name, manufactured by Catalyst Kasei Kogyo) (titania-based composite oxide, 5 to 10 nm), “NZD-8E61” (trade name, manufactured by Sumitomo Osaka Cement) (oxidation) Zirconium sol, 3 to 10 nm) and the like.

  The blending weight ratio of the silsesquioxane derivative (a) and the inorganic fine particles (b) depends on the desired performance such as the refractive index adjustment, transparency and UV resistance, but is generally 90%. : 10 to 10:90 is preferable, and 70:30 to 30:70 is more preferable.

For the purpose of dispersing the inorganic fine particles (b) in the resin composition, a dispersant can be added as necessary. Various surfactants are used as the dispersant, and examples thereof include anionic surfactants such as sulfate esters, carboxylic acids, and polycarboxylic acids, cationic surfactants such as quaternary salts of higher aliphatic amines, and the like. Nonionic surfactants such as fatty acid polyethylene glycol esters, silicon surfactants, fluorine surfactants, polymer surfactants having an amide ester bond, and the like can be mentioned.

The amount of the dispersant added is preferably 0.1 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the inorganic fine particles (b).

In the present invention, the silsesquioxane derivative is cured by forming a cross-linked product. For example, this curing may be performed by using, for example, a cationic polymerization catalyst (Lewis acid catalyst, for example, metal halide (BF ₃ , AlCl _3, etc.). ), Organometallic compounds (C ₂ H ₅ AlCl _{2 and the} like) can be used.

  In the present invention, a curing agent may be used to form a crosslinked product of the silsesquioxane derivative. As such a curing agent, a curing agent capable of reacting with a reactive cyclic ether group can be used. For example, a curing agent used for curing a thermosetting resin can be used. Examples of such a curing agent include acid anhydride compounds, amine compounds, and phenol compounds. Of these, acid anhydrides are preferable in consideration of transparency after curing, and examples include the following compounds: phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride Hexahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, or a mixture of 3-methyl-hexahydrophthalic anhydride and 4-methyl-hexahydrophthalic anhydride, 2,4- Diethyl glutaric anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride, etc. These compounds can be used alone or in combination of two or more.

  The amount of the curing agent is generally different depending on the type of the curing agent, and thus cannot be generally defined. For example, in the case of an acid anhydride compound, an acid anhydride with respect to 1 mol of a reactive cyclic ether group. A ratio of 0.2 to 2.0 mol of the group is preferable, and more preferably 0.5 to 1.0 mol. In the case of other types of curing agents, those skilled in the art can appropriately use them with reference to the above values.

  A curing catalyst can be used together with the curing agent. Examples of the curing catalyst include imidazole compounds, tertiary amines, organic phosphine compounds, or salts thereof. Specifically, for example, as imidazole compounds, 2-methylimidazole, 2-ethylimidazole, 4-methylimidazole, 4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4 -Hydroxymethylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, etc. Can be mentioned. Organic phosphorus compounds can also be used, and specific examples thereof include triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, tri (p-toluyl) phosphine, tri Organophosphines such as (p-methoxyphenyl) phosphine, tri (p-ethoxyphenyl) phosphine, triorganophosphine compounds such as triphenylphosphine and triphenylborane and quaternary phosphonium salts such as tetraphenylphosphonium and tetraphenylborate; And derivatives thereof. Examples of tertiary amines include triethylamine, dimethylethanolamine, dimethylbenzylamine, 2,4,6-tris (dimethylamino) phenol, 1,8-diazabicyclo [5,4,0] undecene. These compounds can be used alone or in combination of two or more.

  These curing catalysts are preferably blended in an amount of 0.01 to 1 part by weight with respect to 100 parts by weight of the silsesquioxane derivative.

  A promoter can be added to the encapsulating resin composition of the present invention as long as the object of the present invention is not impaired. Examples of the polyhydric alcohol used as the cocatalyst include ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Moreover, 1 type, or 2 or more types of these polyhydric alcohols can also be used. It is desirable to use 0.1 to 5.0 equivalents, preferably 0.2 to 3.0 equivalents, relative to the polyhydric alcohol or acid anhydride.

  An antioxidant may be added to the encapsulating resin composition of the present invention in order to prevent oxidative degradation during heating. As this antioxidant, a phenol type, sulfur type, phosphorus type antioxidant, etc. are mentioned, for example.

  Specific examples of the phenolic antioxidant include, for example, 2,6-di-t-butyl-p-cresol, dibutylhydroxytoluene, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol. Monophenols such as stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2 ′ -Methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl Bisphenols such as 2,4,8,10-tetraoxaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, , 3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-t- Butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, 1,3,5-tris ( 3 ', 5'-di-t-butyl-4'-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, tocophenol and other high-molecular phenols .

  Examples of the sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate.

  Phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris (2,4-di-t-butylphenyl) ) Phosphite, cyclic neopentanetetraylbis (octadecyl) phosphite, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4 -Di-t-butyl-4-methylphenyl) phosphite, bis [2-t-butyl-6-methyl-4- {2- (octadecyloxycarbonyl) ethyl} phenyl] hydrogen phosphite, etc. 9,10-dihydro- -Oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Examples thereof include oxaphosphaphenanthrene oxides such as oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

  These antioxidants can be used alone or in combination of two or more. These antioxidants are preferably added in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the silsesquioxane derivative.

  An ultraviolet absorber can be added to the sealing resin composition of the present invention for the purpose of improving light resistance. Specific examples of the ultraviolet absorber include salicylic acids such as phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2- Hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4 Benzophenones such as -methoxy-5-sulfobenzophenone, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hi Roxy-3 ', 5'-ditert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2' -Hydroxy-3 ', 5'-ditert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-ditert-amylphenyl) benzotriazole, 2-{(2 Benzotriazoles such as ′ -hydroxy-3 ′, 3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl} benzotriazole, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1,2,2, , 6-pentamethyl-4-piperidyl) [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] like hindered amines, such as butyl malonate. These can be used alone or in combination of two or more.

  These ultraviolet absorbers are preferably blended in an amount of 0.01 to 1 part by weight per 100 parts by weight of the silsesquioxane derivative.

  A light stabilizer can be added to the sealing resin composition of the present invention for the purpose of improving light resistance. Specific examples of the light stabilizer include, for example, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2, And hindered amines such as 2,6,6-tetramethyl-4-piperidine) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidine) imino}]. These can be used alone or in combination of two or more.

  These light stabilizers are preferably blended in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the silsesquioxane derivative.

  The sealing resin composition of the present invention can be blended with various other additives as long as the object of the present invention is not impaired, for example, a reactive diluent for adjusting the curability of the composition, Examples thereof include a silane coupling agent for further improving the adhesion.

  Examples of the reactive diluent include glycerin diglycidyl ether, butanediol diglycidyl ether, diglycidyl aniline, neopentyl glycol glycidyl ether, cyclohexane dimethanol diglycidyl ether, alkylene diglycidyl ether, polyglycol diglycidyl ether, and polypropylene. Examples thereof include glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, 4-vinylcyclohexene monooxide, vinylcyclohexene dioxide, and methylated vinylcyclohexene dioxide. These reactive diluents can be used alone or in admixture of two or more.

  Examples of the silane coupling include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltriethoxysilane, virnitrimethoxysilane, vinyltriethoxysilane and the like.

  The sealing resin composition of the present invention, together with the silsesquioxane derivative (ii) and the inorganic fine particles (b), the curing agent, curing catalyst, co-catalyst, antioxidant, ultraviolet absorber, if necessary, It can be obtained by blending and mixing one or more of various known additives such as light stabilizers, mold release agents, dyes, pigments and the like into a B-stage.

  That is, the composition of the present invention can be obtained using, for example, the following method. In the first method, the silsesquioxane derivative, the inorganic fine particles, the curing agent, and the curing catalyst are melted and mixed, and the curing reaction proceeds halfway under heating to form a B stage. The standard of B-stage is set so that the gelation time at 150 ° C. is preferably 10 to 70 seconds, more preferably 10 to 40 seconds. Next, the B-staged composition is cooled to room temperature, then pulverized by a known method, and tableted as necessary. After the B-stage, an organic solvent capable of dissolving the composition (for example, alcohols such as methanol, ethanol, isopropanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, toluene, xylene and hexane) , Hydrocarbons such as cyclohexane, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, alkyl ethers such as methyl carbitol and butyl carbitol, sulfoxides such as dimethyl sulfoxide, etc. Then, the mixing may be made uniform. In the second method, each component is dissolved in an organic solvent, and a curing reaction is allowed to proceed under heating in a solution to form a B stage. After the organic solvent is removed and cooled, it is pulverized. The third method is a method in which each component is dissolved in an organic solvent, and then the organic solvent is volatilized and removed without heating.

  The embodiment of the composition of the present invention is not particularly limited as long as it is a B-staged embodiment, but from the viewpoint of transfer molding and handling, for example, after being B-staged, pulverized powder composition, after pulverization The composition may be pelletized or tableted.

  The sealing resin composition of the present invention can be used for transfer molding. In the transfer molding, as a general method, the B-staged molding material is softened in the preheating chamber, and then sent by a plunger through a small hole to the cavity of the sealing mold, where it is cured. Examples of the molding machine include an auxiliary ram type molding machine, a slide type molding machine, a double ram type molding machine, and a low pressure sealing molding machine.

  Examples of the optical element to which the sealing resin composition of the present invention is applied include a light emitting element, a light receiving element, a composite optical element, an optical integrated circuit, and the like. Specific examples include an LED and an LD.

  The optical element of the present invention is an optical element obtained by applying the encapsulating resin composition of the present invention, for example, an LED, particularly, for example, having a peak wavelength of emitted light of 350 to 490 nm as shown in the above-described exemplary embodiment. LED.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, the following description is only for description and the present invention is not limited to these Examples.

Synthesis example 1
Synthesis of silsesquioxane derivative (SQ-1) In a reaction vessel equipped with a stirrer and a thermometer, 50 g of MIBK, 4.7 g of tetramethylammonium hydroxide 20% aqueous solution (tetramethylammonium hydroxide 10.3 mmol), distillation After charging 13.2 (940.0 mmol) g of water, 42.6 g (283.0 mmol) of ethyltrimethoxysilane and 7.4 g (31.0 mmol) of γ-glycidoxypropyltrimethoxysilane were added at 50 to 55 ° C. The mixture was gradually added and stirred for 3 hours. After completion of the reaction, 50 g of MIBK was added to the system, and further washed with 20 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 20 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-1). Mw was 5820. A silsesquioxane derivative mainly having a ladder type structure or a random type structure having a residual silanol peak in the vicinity of 3500 cm ⁻¹ by IR measurement with a dispersity Mw / Mn = 1.7 was obtained.

Synthesis example 2
Synthesis of Silsesquioxane Derivative (SQ-2) In a reaction vessel equipped with a stirrer and a thermometer, MIBK 50 g, tetramethylammonium hydroxide 20% aqueous solution 3.6 g (tetramethylammonium hydroxide 7.9 mmol), distillation After charging 10.1 g (720.0 mmol) of water, 21.5 g (121.0 mmol) of isobutyltrimethoxysilane and 28.5 g (121.0 mmol) of γ-glycidoxypropyltrimethoxysilane at 50 to 55 ° C. Slowly added and left stirring for 3 hours. After completion of the reaction, 50 g of MIBK was added to the system, and further washed with 20 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 20 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-2). Mw was 3200. A silsesquioxane derivative mainly having a ladder type structure or a random type structure having a residual silanol peak in the vicinity of 3500 cm ^{−1 as} measured by IR measurement was obtained.

Synthesis example 3
Synthesis of Silsesquioxane Derivative (SQ-3) In a reaction vessel equipped with a stirrer and a thermometer, MIBK 50 g, tetramethylammonium hydroxide 20% aqueous solution 3.2 g (tetramethylammonium hydroxide 7.0 mmol), distillation After charging 8.9 g (640.0 mmol) of water, 31.2 g (133.0 mmol) of isooctyltrimethoxysilane and 18.8 g (80.0 mmol) of γ-glycidoxypropyltrimethoxysilane were mixed at 50 to 55 ° C. The mixture was gradually added and stirred for 3 hours. After completion of the reaction, 50 g of MIBK was added to the system, and further washed with 20 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 20 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-3). Mw was 2200. A silsesquioxane derivative mainly having a ladder type structure or a random type structure having a residual silanol peak in the vicinity of 3500 cm ⁻¹ by IR measurement with a dispersity Mw / Mn = 1.2 was obtained.

Synthesis example 4
Synthesis of silsesquioxane derivative (SQ-4) In a reaction vessel equipped with a stirrer and a thermometer, MIBK 50 g, tetramethylammonium hydroxide 20% aqueous solution 3.2 g (tetramethylammonium hydroxide 7.0 mmol), distillation After charging 9.0 g (640.0 mmol) of water, 10.6 g (53.0 mmol) of phenyltrimethoxysilane and 39.4 g (160.0 mmol) of 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane were added. The mixture was gradually added at 50 to 55 ° C. and left to stir for 3 hours. After completion of the reaction, 50 g of MIBK was added to the system, and further washed with 20 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 20 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-4). Mw was 4030. A silsesquioxane derivative mainly having a ladder type structure or a random type structure having a residual silanol peak in the vicinity of 3500 cm ⁻¹ by IR measurement with a dispersity Mw / Mn = 1.5 was obtained.

Synthesis example 5
Synthesis of Silsesquioxane Derivative (SQ-5) In a reaction vessel equipped with a stirrer and a thermometer, 50 g of MIBK, 3.0 g of tetramethylammonium hydroxide, 3.0 g (tetramethylammonium hydroxide, 6.6 mmol), distillation After charging 8.5 g (610.0 mmol) of water, 5.0 g (20.0 mmol) of hexyltrimethoxysilane and 45.0 g (182.0 mmol) of 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane were added. The mixture was gradually added at 50 to 55 ° C. and left to stir for 3 hours. After completion of the reaction, 50 g of MIBK was added to the system, and further washed with 20 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 20 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-5). Mw was 4700. A silsesquioxane derivative mainly having a ladder type structure or a random type structure having a residual silanol peak in the vicinity of 3500 cm ⁻¹ by IR measurement with a dispersity Mw / Mn = 1.5 was obtained.

Example 1
20 parts by weight of the silsesquioxane derivative SQ-1 obtained in Synthesis Example 1, 8 parts by weight of an alicyclic acid anhydride (manufactured by Shin Nippon Rika; trade name “Licacid MH-700G”), tetraphenylphosphonium bromide (Made by Hokuko Chemical Co., Ltd.) 0.08 parts by weight, non-volatile content 10% zirconium oxide sol (manufactured by Osaka Sumitomo Cement; trade name “NZD-8E61”) 280 parts by weight were mixed and stirred to obtain a resin composition.

  The obtained resin composition was heated to advance the curing reaction of the resin composition to obtain a B-staged resin having a gel time of about 30 seconds at a temperature of 150 ° C. Next, the solvent contained was removed and cooled. Then, it grind | pulverized and obtained the powdery resin composition. This powdery resin composition was molded into a tablet shape to obtain a sealed resin composition of the present invention. This was used for transfer molding at 150 ° C. for 5 minutes and then cured at 120 ° C. for 10 hours to obtain a cured product having a thickness of 1 mm. The obtained cured product was evaluated by the following method. The results are shown in Table 1.

Example 2
20 parts by weight of the silsesquioxane derivative SQ-2 obtained in Synthesis Example 2, 8 parts by weight of an alicyclic acid anhydride (manufactured by Shin Nippon Rika; trade name “Licacid MH-700G”), tetraphenylphosphonium bromide 0.08 parts by weight (manufactured by Hokuko Chemical Co., Ltd.) and 650 parts by weight of a non-volatile content 10% zirconium oxide sol (manufactured by Osaka Sumitomo Cement; trade name “NZD-8E61”) were mixed and stirred. Next, the solvent was distilled off under reduced pressure to obtain a resin composition. In the same manner as in Example 1, the tableted composition of the present invention was obtained and evaluated. The results are shown in Table 1.

Example 3
20 parts by weight of the silsesquioxane derivative SQ-3 obtained in Synthesis Example 3 and 12.0 parts by weight of 2,4 diethylglutaric anhydride (manufactured by Japan Epoxy Resin; trade name “JER Cure YH-1120”) Then, 0.08 part by weight of tetraphenylphosphonium bromide (manufactured by Hokuko Chemical) and 47 parts by weight of 30% non-volatile content titania-based composite oxide sol (manufactured by Catalyst Kasei Kogyo; trade name “QUEEN TITANIC”) were mixed and stirred. Next, the solvent was distilled off under reduced pressure to obtain a resin composition. In the same manner as in Example 1, the tableted composition of the present invention was obtained and evaluated. The results are shown in Table 1.

Example 4
20 parts by weight of the silsesquioxane derivative SQ-4 obtained in Synthesis Example 4, 18 parts by weight of an alicyclic acid anhydride (manufactured by Shin Nippon Rika; trade name “Licacid MH-700G”), tetraphenylphosphonium bromide 0.08 part by weight (manufactured by Hokuko Chemical Co., Ltd.) and 127 parts by weight of a titania-based composite oxide sol (manufactured by Catalyst Kasei Kogyo; trade name “QUEEN TITANIC”) having a nonvolatile content of 30% were mixed and stirred. Next, the solvent was distilled off under reduced pressure to obtain a resin composition. In the same manner as in Example 1, the tableted composition of the present invention was obtained and evaluated. The results are shown in Table 1.

Example 5
20 parts by weight of the silsesquioxane derivative SQ-5 obtained in Synthesis Example 5, 2,4 diethylglutaric anhydride (manufactured by Japan Epoxy Resin; trade name “JER Cure YH-1129”) 16 glycerin diglycidyl ether Part by weight, 0.08 part by weight of tetraphenylphosphonium bromide (manufactured by Hokuko Chemical), and 280 parts by weight of 30% non-volatile content titania-based composite oxide sol (manufactured by Catalyst Kasei Kogyo; trade name “QUEEN TITANIC”) were mixed and stirred. Next, the solvent was distilled off under reduced pressure to obtain a resin composition. In the same manner as in Example 1, the tableted composition of the present invention was obtained and evaluated. The results are shown in Table 1.

Comparative Example 1
20 parts by weight of a bisphenol A type epoxy resin (made by Japan Epoxy Resin; trade name “Epicoat 1001”), alicyclic acid anhydride (manufactured by Shin Nippon Rika; 16 parts by trade name “MH-700G”) (manufactured by Shin Nippon Rika Co., Ltd.) ) 0.1 parts of tetraphenylphosphonium bromide (manufactured by Hokuko Chemical Co., Ltd.) were mixed to obtain a resin composition, which was evaluated by obtaining a tableted composition in the same manner as in Example 1. The results are shown in Table 1. .

Comparative Example 2
10 parts by weight of hydrogenated bisphenol A type epoxy resin (made by Japan Epoxy Resin; trade name “YX8000”), 10 parts by weight of bisphenol A type epoxy resin (made by Japan Epoxy Resin; trade name “Epicoat 1001”), alicyclic acid anhydride Product (manufactured by Nippon Nippon Chemical Co., Ltd .; trade name “MH-700G” 10 parts: (manufactured by Nippon Steel Chemical Co., Ltd.) 0.1 part of tetraphenylphosphonium bromide (manufactured by Hokuko Chemical) was mixed to obtain a resin composition. A tableted composition was obtained and evaluated in the same manner as in Table 1. The results are shown in Table 1.

Comparative Example 3
20 parts by weight of the silsesquioxane derivative SQ-1 obtained in Synthesis Example 1, 8 parts by weight of an alicyclic acid anhydride (manufactured by Shin Nippon Rika; trade name “Licacid MH-700G”), tetraphenylphosphonium bromide (Hokuko Chemical Co., Ltd.) 0.08 parts by weight were mixed to obtain a resin composition. A tableted composition was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Evaluation method A test piece was prepared using the composition of each example and the resin or composition of each comparative example (120 ° C. for each sealing resin composition of Examples 1 to 5 and Comparative Examples 1, 2 and 3). For each of the 10 h curing conditions), the performance was evaluated by the following method. The results are shown in Table 1.
(1) Refractive index: Measured at a sample temperature of 25 ° C. using an Abbe refractometer.
(2) Transparency: A cured product having a thickness of 1 mm was prepared under the above-mentioned curing conditions, and the transmittance of 450 nm wavelength light was determined with a spectrophotometer ultraviolet ray-2450 manufactured by Shimadzu Corporation.
(3) Ultraviolet resistance: The transmittance of 450 nm wavelength light after exposure of a cured product having a thickness of 1 mm to a metalling weather meter (M6T manufactured by Suga Test Instruments Co., Ltd.) at 83 ° C. for 100 hours was determined.

  From the results of the Examples, Examples 1 to 5 using the sealing resin composition mainly composed of the silsesquioxane derivative and the inorganic fine particles in the present invention are UV resistant and refracting while maintaining high transparency. It was clear that it was significantly superior. In addition, although the epoxy resin of Comparative Examples 1 and 2 belonging to the prior art was excellent in transparency, the ultraviolet resistance was extremely low and the refractive index was also low. The silsesquioxane derivative containing no inorganic fine particles of Comparative Example 3 was excellent in transparency and ultraviolet resistance, but had a low refractive index.

  The encapsulating resin composition of the present invention enables mass production of optical elements by transfer molding, and simultaneously overcomes the low ultraviolet resistance and low refractive index that were disadvantages of conventional epoxy resins. These are extremely suitable as an optical element sealing material excellent in transparency, ultraviolet resistance, and light extraction efficiency. For example, they are useful as LED sealing materials that are expected to further increase in luminance in the future.

Claims (9)

(A) The following general formula (1):

(In the formula, each of a plurality of R's independently represents a methyl group or an ethyl group, and R1 represents an alkyl group having 1 to 20 carbon atoms, or has a hydrocarbon group having 1 to 8 carbon atoms. A trialkoxysilane (A) represented by:
The following general formula (2):

(Wherein a plurality of R's independently represent a methyl group or an ethyl group, and R2 represents a substituent containing a reactive cyclic ether group) and a trialkoxysilane (B) represented by B-stage encapsulating resin for optical elements, characterized by comprising a silsesquioxane derivative of ladder type or random type structure obtained by decomposition and co-condensation, and (b) inorganic fine particles as main components Composition. The encapsulating resin composition according to claim 1, wherein the reactive cyclic ether group is at least one selected from the group consisting of an epoxy group, a 3,4-epoxycyclohexyl group, and an oxetanyl group. The trialkoxysilane (A) is a phenyl group optionally having an alkyl group having 2 to 8 carbon atoms or a hydrocarbon group having 1 to 2 carbon atoms in the general formula (1). Or the sealing resin composition of 2. The encapsulating resin composition according to claim 3, wherein the trialkoxysilane (A) has R1 as ethyl, isobutyl, isooctyl or phenyl, and the silsesquioxane derivative has a ladder structure as a main component. The sealing resin composition according to any one of claims 1 to 4, wherein a compounding molar ratio of the trialkoxysilane (A) and the trialkoxysilane (B) is 10:90 to 90:10. The inorganic fine particles (b) are at least one selected from the group consisting of (a) titanium oxide, (b) zirconium oxide, and (c) a composite oxide containing titanium and / or zirconium atoms. The sealing resin composition in any one of these. The encapsulating resin composition according to any one of claims 1 to 6, wherein the weight ratio of the silsesquioxane derivative (i) to the inorganic fine particles (b) is 90:10 to 10:90. The optical element formed by sealing with the sealing resin composition in any one of Claims 1-7. The optical element according to claim 8, which is an LED having a peak wavelength of emitted light of 350 to 490 nm.