JP2007056146A - Optical device encapsulation resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an encapsulation composition for transfer molding which is excellent in transparency, UV resistance and thermal shock resistance and suitable for use in optical devices. <P>SOLUTION: The optical device encapsulation resin composition comprises a curing agent and silsesquioxane derivative with a ladder or random structure obtained by co-hydrolyzing and co-condensating (A) trialcoxysilane expressed by R<SB>1</SB>Si(OR)<SB>3</SB>(R's are each independently a methyl group or an ethyl group; R<SB>1</SB>is an alkyl group or a phenyl group) and (B) a trialcoxysilane expressed by R<SB>2</SB>Si(OR)<SB>3</SB>(R's are each independently a methyl group or an ethyl group; R<SB>2</SB>is a substituent containing a reactive cyclic ether group) and is B-staged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an encapsulating resin composition for optical elements, and more particularly relates to an encapsulating resin composition for optical elements by a transfer molding method, which is excellent in transparency and UV resistance and excellent in thermal shock resistance. .

  Optical elements include various lasers (especially semiconductor lasers) and light-emitting elements such as light-emitting diodes (LEDs), light-receiving elements, composite optical elements, and optical integrated circuits. A sealing resin composition is used for these optical elements. ing. In recent years, light-emitting elements having a short emission peak wavelength have been developed, and correspondingly, optical elements have been developed to be compatible with short-wavelength light. In recent years, the brightness of light emitting elements having a short peak wavelength of light emission has been dramatically increased, and accordingly, the amount of heat generated by an optical element, for example, a light emitting electronic device, tends to be further increased. The performance required for the sealing resin is higher in terms of UV resistance, heat resistance, and the like.

General-purpose epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin have been widely used for transfer molding and sealing because of their excellent transparency, thermal shock and workability. However, since these epoxy resins contain aromatics in the structure, they have a problem that yellowing easily occurs due to UV exposure.

As for silsesquioxane, for example, an optical waveguide device using a polymer film obtained by curing an oxetane ring-containing silsesquioxane (see, for example, Patent Document 1 and Patent Document 2) is known. However, these techniques are not techniques that can be used as transfer molding encapsulants for optical semiconductor elements. That is, since these conventional technologies all form an optical waveguide, the technical field relating to the sealing material is different from that of the sealing material, and the formation thickness required for the sealing material is realized. It cannot be used instead of resin. Further, it cannot be made into a B-stage once to form a transfer molding resin composition. 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, the reaction proceeds moderately and is in a semi-cured state.
JP 2003-21735 A JP 2004-189840 A

  In view of the above-mentioned present situation, an object of the present invention is to provide a composition for transfer molding and sealing suitable for an optical element, which is excellent in transparency and UV resistance and excellent in thermal shock resistance.

  As a result of intensive studies to solve the above problems, the inventors have achieved excellent light transmittance with a sealing resin mainly composed of a silsesquioxane derivative having a ladder type structure or a random type structure into which a specific type of side chain is introduced, Based on this finding, the present invention was completed based on the finding that it has both heat resistance and thermal shock resistance. 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 It is an encapsulating resin composition for optical elements, which mainly contains a silsesquioxane derivative having a ladder type structure or a random type structure obtained by decomposition and cocondensation.
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 thermal shock resistance by the above-mentioned structure.
(2) The sealing resin composition of this invention is excellent in adhesive strength by the above-mentioned structure.
(3) The sealing resin composition of the present invention has transparency, heat deterioration resistance, UV resistance, and thermal shock resistance due to the above-described configuration, and is required for a sealing material for high brightness green to blue light elements. Each required performance can be satisfied at a sufficient level.
(4) The sealing resin composition of this invention can seal an optical element by transfer molding instead of the conventional epoxy resin by the above-mentioned structure.

  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 crosslinking density after curing is increased, and the thermal shock resistance may be deteriorated. If it exceeds 90, the mechanical strength may be lowered.

  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 1500 or less, the heat resistance may not be sufficient, and if it exceeds 10,000, the viscosity may be too 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.

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, 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.

  The blending amount of such a curing catalyst is preferably 0.05 to 5.0 parts by weight, more preferably 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the silsesquioxane derivative.

  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 blended in an amount of 0.01 to 10 parts by weight with respect to 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 10 parts by weight with respect to 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 10 parts by weight per 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 purpose of the present invention is not impaired, for example, a diluent for adjusting the viscosity of the composition, and adhesiveness. Examples thereof include a silane coupling agent for further improvement.

  Examples of the 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 glycol diglycol. Examples thereof include glycidyl 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 combination of two or more.

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

  The sealing resin composition of the present invention, together with the silsesquioxane derivative, is optionally selected from the above curing agents, curing catalysts, antioxidants, ultraviolet absorbers, light stabilizers, and other additives. It can be obtained by blending and mixing two or more.

  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. A light emitting element such as an LED is generally composed of an LED chip, a lead frame, a gold wire, and a sealing resin. For example, in the structure of a near-ultraviolet LED, an electrode wiring submount is generally installed on a metal stem, and an LED chip is mounted thereon. A near-ultraviolet LED element is formed by sealing the chip on the submount with the composition of the present invention. Moreover, in order to set it as white light emitting LED, the fluorescent substance layer may be arrange | positioned on the LED chip. This phosphor layer can be formed using the composition of the present invention. In general, a sealing material is further applied thereon to form a white light emitting LED. Similarly, high brightness blue light emitting LEDs can be formed using the compositions of the present invention.

  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.

Synthesis example 1
Synthesis of Silsesquioxane Derivative (SQ-1) In a reaction vessel equipped with a stirrer and a thermometer, 150 g of MIBK, 4.9 g of a 20% aqueous solution of tetramethylammonium hydroxide (tetramethylammonium hydroxide 1.1 mmol), distilled After charging 13.8 g of water, 44.7 g (297.5 mmol) of ethyltrimethoxysilane and 10.0 g (42.5 mmol) of γ-glycidoxypropyltrimethoxysilane were gradually added at 50 to 55 ° C. Stir for hours. After completion of the reaction, 150 g of MIBK was added to the system, and further washed with 60 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 80 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-1). Mw was 8020. 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 was obtained.

Synthesis example 2
Synthesis reaction of silsesquioxane derivative (SQ-2) In a reaction vessel equipped with a stirrer and a thermometer, MIBK 180 g, tetramethylammonium hydroxide 20% aqueous solution 11.4 g (tetramethylammonium hydroxide 2.5 mmol), distilled After charging 11.4 g of water, 27.6 g (382.0 mmol) of isooctyltrimethoxysilane and 90.4 g (382.0 mmol) of γ-glycidoxypropyltrimethoxysilane were gradually added at 50 to 55 ° C., The mixture was left stirring for 3 hours. After completion of the reaction, 150 g of MIBK was added to the system, and further washed with 60 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 80 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-4). Mw was 2800. 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, 150 g of MIBK, 4.8 g of a 20% aqueous solution of tetramethylammonium hydroxide (tetramethylammonium hydroxide 1.1 mmol), distillation After charging 13.5 g of water, 107.4 g (541.0 mmol) of phenyltrimethoxysilane and 42.6 g (180.0 mmol) of γ-glycidoxypropyltrimethoxysilane were gradually added at 50 to 55 ° C. 3 Stir for hours. After completion of the reaction, 150 g of MIBK was added to the system, and further washed with 60 g of distilled water until the pH of the aqueous layer became neutral. Next, after washing twice with 80 g of distilled water, MIBK was distilled off under reduced pressure to obtain the target compound (SQ-3). Mw was 4800. 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.

  It does not specifically limit as a manufacturing method of the composition of this invention, For example, the following methods etc. can be used. The first method is silsesquioxane in the present invention, or preferably a curing agent and a curing catalyst, and, if applicable, an epoxy resin is further added, melt-mixed, and the curing reaction is performed under heating. To 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, the composition may be once dissolved in an organic solvent that can be dissolved to make the mixing 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 sealing 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.

  The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 and 2
After mixing and heating and kneading each component and composition shown in Table 1, the curing reaction of the resin composition is advanced, and the B-staged resin having a gelation time of about 30 seconds at a temperature of 150 ° C. is crushed. A powdery resin composition was obtained. This powdery resin composition was molded into a tablet, and after using this to perform transfer molding at 150 ° C./5 minutes, it was further cured at 120 ° C. for 10 hours to obtain a cured product having a thickness of 1 mm.
Using this cured product as a test piece, the following method was used to determine the change in the transmittance of near-ultraviolet to blue light before and after exposure to the metering weather meter. The UV characteristics were measured. The results are shown in Table 1, respectively. The abbreviations in the table are as follows.
Epicoat 828: Bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.) OX-SQ: (Toa Gosei Chemical Co., Ltd.) MH-700G: Methylhexahydrophthalic anhydride-hexahydrophthalic anhydride mixture (New Nippon Rika Co., Ltd.) TPP-PB: Triphenylphosphine (manufactured by Hokuko Chemical) 2E4MZ: 2-ethyl-4methylimidazole (manufactured by Shikoku Chemicals)

Evaluation method (1) Thermal shock resistance: The cured product obtained by transfer molding is exposed to conditions of −40 ° C./15 minutes, and then subjected to a temperature cycle of 1000 times exposed to conditions of 120 ° C./15 minutes. The cracks of the cured product were observed with a microscope. The evaluation criteria are as follows.
○: No peeling or cracking Δ: Fine peeling or cracking occurred ×: Separation or cracking occurred (2) Heat resistance deterioration: 1 mm thick cured product after exposure to 150 ° C. for 100 hours The transmittance of 470 m wavelength light was determined.
(3) UV resistance: A transmittance of 470 nm wavelength light after exposure of a cured product having a thickness of 1 mm to a metering weather meter (M6T manufactured by Suga Test Instruments Co., Ltd.) at 63 ° C. for 100 hours was determined.
(4) Adhesive strength: Two aluminum test pieces were bonded to each other with an area of 20 mm × 10 mm through a resin having a predetermined composition, and cured at 120 ° C. for 10 hours. This was pulled to both sides at a speed of 5 mm / min in an Instron universal test, and the strength when broken by the bonded area was taken as the adhesive strength.
(5) Transparency: A cured product having a thickness of 1 mm was prepared under the above-mentioned curing conditions, and the transmittance of 470 nm wavelength light was determined using a spectrophotometer UV-2450 manufactured by Shimadzu Corporation.

  From the above examples, the cured products of Examples 1 to 6 in which the silsesquioxane derivative was cured with an acid anhydride showed no substantial decrease in transmittance even after being subjected to UV exposure. In Comparative Example 1 which is a transparent epoxy resin cured product, the transmittance after receiving UV exposure was significantly reduced. In the thermal shock resistance, the cured products of Examples 1 to 6 did not generate any peeling and cracks, and were significantly superior to Comparative Examples 1 and 2.

  The present invention overcomes the drawbacks of conventional epoxy resin-based sealants and is extremely suitable as a sealing material for optical elements for transfer molding that replaces conventional epoxy resins.

Claims (9)

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-stage encapsulating resin composition for optical elements, characterized by comprising a silsesquioxane derivative having a ladder type structure or a random type structure obtained by decomposition and cocondensation as a main component. 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. Furthermore, the sealing resin composition in any one of Claims 1-5 containing the hardening | curing agent and / or hardening catalyst which can react with a reactive cyclic ether group. The sealing resin composition according to any one of claims 1 to 6, further comprising any one of an antioxidant, an ultraviolet absorber, a light stabilizer or other additives, or a mixture of at least two of them. . 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.