JP2010053199A - Resin composition for sealing optical semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for sealing an optical semiconductor which can give a cured product to exert an excellent crack resistance while maintaining a high heat resistance and the transparency. <P>SOLUTION: This resin composition for sealing an optical semiconductor contains: a rubber particle-dispersed curable epoxy resin (A) in which an alicyclic epoxy resin is made to disperse such rubber particles that comprise a polymer having a (meth)acrylic acid ester as an essential monomer component and have on the surface a hydroxyl group and/or a carboxyl group as a functional group reactive with an epoxy group and have an average particle diameter of 10-500 nm, a maximal particle diameter of 50-1,000 nm and have a difference in the refractive index from a cured product of this resin composition for sealing an optical semiconductor of within ±0.02; a multifunctional thiol (B); a curing agent (C); and a curing accelerator (D). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical semiconductor sealing resin composition, a cured product obtained by curing the same, and an optical semiconductor device in which an optical semiconductor element is sealed using the same. More specifically, a resin composition for encapsulating an optical semiconductor comprising a thermosetting epoxy resin composition capable of obtaining a cured product having improved crack resistance without reducing heat resistance and transparency, and curing the resin composition. The present invention relates to a cured product obtained and an optical semiconductor device in which an optical semiconductor element is sealed using the cured product.

  A liquid epoxy compound having an alicyclic skeleton having good transparency and heat resistance is frequently used for an epoxy resin composition for sealing an optical semiconductor element. Examples of such epoxy compounds include Celoxide 2021 (3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate) and Celoxide 2081 (3,4-epoxycyclohexyl), both manufactured by Daicel Chemical Industries, Ltd. Methyl-3 ′, 4′-epoxycyclohexanecarboxylate and ε-caprolactone adduct), Celoxide 3000 (1,2,8,9-diepoxy limonene) and the like.

  Epoxy compounds having a 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate structure represented by Celoxide 2021 are used to produce cured products with excellent heat resistance and transparency. Used in sealing resins. However, alicyclic epoxy compounds such as Celoxide 2021 have a problem in toughness, and the reliability of electronic components is reduced due to the occurrence of cracks in the heat cycle test.

  As a proposal for improving such a problem, for example, an epoxy resin composition for encapsulating an optical semiconductor containing diglycidyl ether of bisphenol A that has been hydrogenated is known (for example, see Patent Document 1). Furthermore, as a means for imparting toughness to the epoxy resin, a technique of dispersing a core-shell polymer in the epoxy resin is known (for example, see Patent Document 2). Further, a method has been proposed in which polyether polyol is blended in an epoxy resin, and particles having a core structure of butadiene rubber and a shell structure of methyl methacrylate resin are dispersed in the epoxy resin (for example, patents) Reference 3).

  On the other hand, as an example of using thioalcohol as a resin for encapsulating an optical semiconductor to increase the refractive index of the resin, an example of using a polyfunctional thioalcohol as a curing agent for curing an aliphatic epoxy resin (for example, see Patent Document 4), Examples in which monoalkylthioalcohol is used as a resin for encapsulating an optical semiconductor are known (see, for example, Patent Documents 5, 6, 7, and 8).

  However, the cured product of the epoxy resin composition for sealing an optical semiconductor described in Patent Document 1 has problems in terms of coloring, weather resistance, heat resistance, and the like. The epoxy resin composition described in Patent Document 2 does not mention any transparency. Moreover, the epoxy resin composition described in Patent Document 3 is a photocurable resin composition by ultraviolet rays, and has not found a feature in thick film curing by casting heating. Further, it is not satisfactory in terms of transparency of the cured product. In the example of using thioalcohol described in Patent Document 4 as a curing agent, only thioalcohol is used as a curing agent because Tg becomes too low and it is necessary to perform a special surface treatment on the surface of the substrate. It's not very practical. In the examples using monoalkyl thiols described in Patent Documents 5, 6, 7, and 8, since monofunctional thioalcohol is used, there is a risk of causing a decrease in strength, and transfer molding using a solid epoxy resin composition is also possible. This is an application example, and there is a problem that equipment costs are incurred, such as preparing a refrigerated storage facility for molds and resins when applied.

Japanese Patent Laid-Open No. 9-255564 JP 2005-255822 A JP-A-11-240939 JP 2007-109915 A JP-A-11-269351 JP 2002-353518 A JP 2003-268200 A JP 2007-197627 A

The object of the present invention is to improve the above-mentioned problems, and to provide a cured product having crack resistance imparted while maintaining high heat resistance and transparency without lowering the glass transition temperature (Tg) of the cured product. Optical semiconductor sealing resin composition obtained, cured product obtained by curing the optical semiconductor sealing resin composition, and light obtained by sealing an optical semiconductor element with the optical semiconductor sealing resin composition It is to provide a semiconductor device.
Another object of the present invention is to cure the resin composition for optical semiconductor encapsulation, in addition to the above-mentioned properties, by further curing the resin composition for optical semiconductor encapsulation having a low viscosity and excellent storage stability and processability. An object of the present invention is to provide an optical semiconductor device in which an optical semiconductor element is sealed with the obtained cured product and the resin composition for optical semiconductor sealing.

  As a result of intensive studies to solve the above problems, the present inventors have found that the problem of heat cycleability can be improved by dispersing specific rubber particles in an alicyclic epoxy resin and improving the elastic properties. . Also, by blending a curable epoxy resin in which rubber particles are dispersed and a polyfunctional thiol, an optically uniform cured product can be obtained, and there is no problem of occurrence of defective curing sites, and the transparency of the cured product is obtained. It was found that a resin composition for encapsulating an optical semiconductor capable of imparting toughness (low bending elastic modulus, high bending strength) while maintaining heat resistance was obtained. The present invention has been completed based on these findings and further research.

  That is, the present invention is composed of a polymer having (meth) acrylic acid ester as an essential monomer component, and has a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with an epoxy group on the surface, and an average particle diameter of 10 nm. Disperse rubber particles in an alicyclic epoxy resin having a maximum particle diameter of 50 nm to 1000 nm and a difference in refractive index within ± 0.02 with respect to the cured product of the resin composition for encapsulating an optical semiconductor. A resin composition for encapsulating an optical semiconductor comprising a rubber particle-dispersed curable epoxy resin (A), a polyfunctional thiol (B), a curing agent (C), and a curing accelerator (D) is provided.

  The present invention is also composed of a polymer having (meth) acrylic acid ester as an essential monomer component, and has a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with an epoxy group on the surface, and an average particle size of 10 nm. Disperse rubber particles in an alicyclic epoxy resin having a maximum particle diameter of 50 nm to 1000 nm and a difference in refractive index within ± 0.02 with respect to the cured product of the resin composition for encapsulating an optical semiconductor. An optical semiconductor encapsulating resin composition comprising a rubber particle-dispersed curable epoxy resin (A), a polyfunctional thiol (B), and a thermosetting catalyst (E) is provided.

  The polyfunctional thiol (B) is preferably liquid at 25 ° C. Moreover, it is preferable that the said hardening | curing agent (C) is a liquid acid anhydride at 25 degreeC.

  The present invention further provides a cured product obtained by curing each of the above resin compositions for encapsulating an optical semiconductor.

  The present invention further provides an optical semiconductor device in which an optical semiconductor element is sealed with each of the above-mentioned resin compositions for sealing an optical semiconductor.

  The resin composition for encapsulating an optical semiconductor of the present invention contains a curable epoxy resin in which rubber particles having specific characteristics are dispersed in an alicyclic epoxy resin and a polyfunctional thiol, and therefore does not contain rubber particles. However, the cured product obtained by heat curing is optically homogeneous, and there is no problem of occurrence of poorly cured sites. Further, since the rubber particles are designed with a particle size that does not generate haze even at high temperatures, the transparency is high. Furthermore, since it contains the specific rubber particles, it has a low bending elastic modulus and a high bending strength, and thus has excellent crack resistance, and has a high glass transition temperature and excellent heat resistance.

[Resin composition for optical semiconductor encapsulation]
The first resin composition for encapsulating an optical semiconductor of the present invention comprises a rubber particle dispersion curable epoxy resin (A), a polyfunctional thiol (B), a curing agent (C), and a curing accelerator (D). Contains as an ingredient. The second resin composition for encapsulating an optical semiconductor of the present invention contains a rubber particle dispersion curable epoxy resin (A), a polyfunctional thiol (B), and a thermosetting catalyst (E) as essential components. In addition to the above, the resin composition for sealing an optical semiconductor of the present invention may contain various additives as long as the effects of the present invention are not impaired.

[Rubber particle dispersion curable epoxy resin (A)]
The rubber particle dispersion curable epoxy resin (A) in the present invention is composed of a polymer having (meth) acrylic acid ester as an essential monomer component, and has hydroxyl groups and / or carboxyl groups as functional groups capable of reacting with epoxy groups on the surface. A cured product of the resin composition for encapsulating an optical semiconductor (= the resin composition for encapsulating an optical semiconductor of the present invention) having an average particle diameter of 10 nm to 500 nm, a maximum particle diameter of 50 nm to 1000 nm, and The rubber particles (a) having a refractive index difference within ± 0.02 are dispersed in the alicyclic epoxy resin (b).

(Rubber particles (a))
The rubber particle (a) in the present invention has a multilayer structure (core-shell structure) comprising a core portion having rubber elasticity and at least one shell layer covering the core portion. Moreover, it is comprised with the polymer which uses (meth) acrylic acid ester as an essential monomer component, and has the hydroxyl group and / or carboxyl group which can react with the epoxy group of an alicyclic epoxy resin on the surface. When a hydroxyl group and / or a carboxyl group are not present on the rubber particle surface, the cured product may become cloudy and the transparency may be lowered by a thermal shock test, which is not preferable.

  As a monomer component constituting the polymer of the core portion having rubber elasticity, (meth) acrylate such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate is essential. Examples of monomer components other than (meth) acrylic acid esters include silicones such as dimethylsiloxane and phenylmethylsiloxane, aromatic vinyl compounds such as styrene and α-methylstyrene, acrylonitrile, methacrylonitrile, and the like. Examples thereof include conjugated dienes such as nitrile, butadiene and isoprene, and olefins such as urethane, ethylene, propylene and isobutene.

  In the present invention, as a monomer component constituting the core portion having rubber elasticity, together with (meth) acrylic acid ester, one or more selected from silicone, aromatic vinyl compound, nitrile and conjugated diene are combined. For example, a binary copolymer such as (meth) acrylic acid ester / aromatic vinyl compound, (meth) acrylic acid ester / conjugated diene; (meth) acrylic acid ester / aromatic vinyl / conjugated Examples thereof include terpolymers such as dienes.

  In addition to the above monomer components, the core portion having rubber elasticity includes divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl maleate, triallyl cyanurate, diallyl phthalate, butylene glycol diacrylate, etc. The molecule may contain a structural unit corresponding to a reactive crosslinking monomer having two or more reactive functional groups.

  As the monomer component constituting the core portion having rubber elasticity in the present invention, (meth) acrylic acid ester / aromatic vinyl compound binary copolymer (especially butyl acrylate / styrene) and the like (meta) ) A copolymer containing at least an acrylic acid ester and an aromatic vinyl compound as essential monomer components is preferable because the refractive index of the rubber particles can be easily adjusted.

  The core portion having rubber elasticity can be produced by a commonly used method, and examples thereof include a method of polymerizing the above monomer by an emulsion polymerization method. As the emulsion polymerization method, the whole amount of the monomer may be charged and polymerized in a lump, or after polymerizing a part of the monomer, the remainder may be added continuously or intermittently to polymerize, Furthermore, a polymerization method using seed particles may be used.

  The shell layer is preferably made of a polymer different from the polymer constituting the core portion. Further, the shell layer has a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with the epoxy group of the alicyclic epoxy resin. Thereby, adhesiveness can be improved at the interface with the alicyclic epoxy resin, and excellent crack resistance can be obtained by curing the resin composition for optical semiconductor encapsulation containing the rubber particles having the shell layer. A transparent cured product having white turbidity can be obtained. Moreover, it can prevent that the glass transition temperature of hardened | cured material falls.

  As a monomer component which comprises a shell layer, (meth) acrylic acid esters, such as methyl (meth) acrylate, ethyl (meth) acrylate, and (butyl) (meth) acrylate, are essential, for example, a core part is comprised ( When the (meth) acrylate is butyl acrylate, the shell layer is made of (meth) acrylate other than butyl acrylate (for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl methacrylate). Is preferably used. Examples of the monomer component that may be contained in addition to the (meth) acrylic acid ester include aromatic vinyl compounds such as styrene and α-methylstyrene, nitriles such as acrylonitrile and methacrylonitrile. In the present invention, as a monomer component constituting the shell layer, it is preferable to contain the above monomers alone or in combination of two or more together with (meth) acrylic acid ester, and in particular, at least an aromatic vinyl compound is included. It is preferable that the refractive index of the rubber particles can be easily adjusted.

  Furthermore, as a monomer component having a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with an epoxy group of an alicyclic epoxy resin, a hydroxyalkyl (meth) acrylate such as 2-hydroxyethyl (meth) acrylate, (meta It is preferable to contain monomers such as α, β-unsaturated carboxylic acid such as acrylic acid and α, β-unsaturated carboxylic acid anhydride such as maleic anhydride.

  In the present invention, the monomer component constituting the shell layer preferably contains one or more selected from the above monomers together with (meth) acrylic acid ester, for example, (meth) acrylic Examples thereof include terpolymers such as acid ester / aromatic vinyl compound / hydroxyalkyl (meth) acrylate, (meth) acrylic acid ester / aromatic vinyl compound / α, β-unsaturated carboxylic acid, and the like.

  In addition to the above monomers, the shell layer is composed of divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl maleate, triallyl cyanurate, diallyl phthalate, butylene glycol diacrylate, as well as the core portion. A structural unit corresponding to a reactive crosslinking monomer having two or more reactive functional groups may be contained in the molecule.

  As a method of coating the core portion with the shell layer, for example, a method of coating the surface of the core portion having rubber elasticity obtained by the above method by applying a copolymer constituting the shell layer, by the above method Examples thereof include a method of graft polymerization using the obtained core portion having rubber elasticity as a trunk component and each component constituting the shell layer as a branch component.

  The average particle diameter of the rubber particles in the present invention is in the range of 10 to 500 nm, preferably about 20 to 400 nm. The maximum particle size of the rubber particles is in the range of 50 to 1000 nm, preferably about 100 to 800 nm. When the average particle diameter exceeds 500 nm, or when the maximum particle diameter of the rubber particles exceeds 1000 nm, the transparency of the cured product tends to decrease and the light intensity of the optical semiconductor tends to decrease. On the other hand, if the average particle size is less than 10 nm or the maximum particle size of the rubber particles is less than 50 nm, the crack resistance tends to be reduced.

  The refractive index of the rubber particles in the present invention is, for example, 1.40 to 1.60, preferably about 1.42 to 1.58. Further, the difference between the refractive index of the rubber particles and the refractive index of the cured product obtained by curing the resin composition for encapsulating an optical semiconductor containing the rubber particles is within ± 0.02, among which ± 0 Preferably it is within .018. If the difference in refractive index exceeds ± 0.02, the transparency of the cured product is reduced, sometimes it becomes cloudy, the light intensity of the optical semiconductor tends to decrease, and the function of the optical semiconductor may be lost. . The refractive index of the rubber particles can be adjusted by the kind and content of the monomer component constituting the polymer of the core portion and the shell layer.

  The refractive index of the rubber particles is, for example, by casting 1 g of rubber particles into a mold and compression molding at 210 ° C. and 4 MPa to obtain a flat plate having a thickness of 1 mm. From the obtained flat plate, a test piece having a length of 20 mm × width of 6 mm And using a multi-wavelength Abbe refractometer (trade name “DR-M2”, manufactured by Atago Co., Ltd.) in a state where the prism and the test piece are in close contact using monobromonaphthalene as an intermediate solution, It can be determined by measuring the refractive index at 20 ° C. and sodium D line.

  The refractive index of the cured product of the resin composition for encapsulating an optical semiconductor is, for example, a test piece of 20 mm long × 6 mm wide × 1 mm thick from a cured product obtained by the heat curing method described in the following section of the optical semiconductor device. And using a multi-wavelength Abbe refractometer (trade name “DR-M2”, manufactured by Atago Co., Ltd.) in a state where the prism and the test piece are in close contact using monobromonaphthalene as an intermediate solution, It can be determined by measuring the refractive index at 20 ° C. and sodium D line.

(Alicyclic epoxy resin (b))
The alicyclic epoxy resin (b) in the present invention is an alicyclic compound having two or more epoxy groups composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring, and is generally used. One or two or more can be arbitrarily selected and used. As the alicyclic epoxy resin in the present invention, those exhibiting a liquid state at normal temperature (25 ° C.) are preferable from the viewpoint of workability during preparation and casting.

  The alicyclic epoxy resin in the present invention is particularly preferably an alicyclic epoxy resin represented by the following formula (1) in terms of transparency and heat resistance.

式中、Ｙは連結基を示し、例えば、単結合、２価の炭化水素基、カルボニル基、エーテル結合、エステル結合、アミド結合、及びこれらが複数個連結した基等が挙げられる。

In the formula, Y represents a linking group, and examples thereof include a single bond, a divalent hydrocarbon group, a carbonyl group, an ether bond, an ester bond, an amide bond, and a group in which a plurality of these are linked.

  Examples of the divalent hydrocarbon group include a linear or branched alkylene group having 1 to 18 carbon atoms, a divalent alicyclic hydrocarbon group, and a group in which two or more of these are bonded. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene groups. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, And divalent cycloalkylene groups (including cycloalkylidene groups) such as 1,4-cyclohexylene and cyclohexylidene groups.

  Typical examples of the alicyclic epoxy resin represented by the formula (1) include compounds represented by the following formulas (1a) to (1i). In the following formulae, n1 to n8 each represent an integer of 1 to 30. In formula (1e), —O—R—O— represents a residue of a diol. Examples of R include a divalent hydrocarbon group, a carbonyl group, an ether bond, an ester bond, an amide bond, and a group in which a plurality of these are linked. Examples of the divalent hydrocarbon group include the same groups as the divalent hydrocarbon group in Y above.

  These alicyclic epoxy resins can be used alone or in combination of two or more. For example, commercial products such as trade names “Celoxide 2021P” and “Celoxide 2081” (manufactured by Daicel Chemical Industries, Ltd.). Can also be used.

  The rubber particle dispersion curable epoxy resin (A) in the present invention is obtained by dispersing the rubber particles (a) in the alicyclic epoxy resin (b). As a compounding quantity of a rubber particle, it can adjust suitably as needed, for example, about 0.5 to 30 weight% with respect to the rubber particle dispersion | distribution curable epoxy resin (A) whole quantity, Preferably, 1- About 20% by weight. If the amount of rubber particles used is less than 0.5% by weight, the crack resistance tends to be reduced. On the other hand, if the amount of rubber particles used exceeds 30% by weight, the heat resistance and transparency tend to be reduced. is there.

  The viscosity of the rubber particle dispersion curable epoxy resin (A) is preferably 400 mPa · s to 50,000 mPa · s at 25 ° C., and more preferably 500 mPa · s to 10000 mPa · s. When the viscosity (25 ° C.) of the rubber particle dispersion curable epoxy resin (A) is less than 400 mPa · s, the transparency tends to decrease, whereas the viscosity of the rubber particle dispersion curable epoxy resin (A) (25 ° C.). When it exceeds 50000 mPa · s, the production of the rubber particle dispersion curable epoxy resin (A) and the production of the optical semiconductor sealing resin composition tend to decrease in productivity.

  The method for producing the rubber particle dispersion curable epoxy resin (A) is not particularly limited, and a conventional method for dispersing the rubber particles in the resin can be used. For example, the rubber particles are dehydrated and dried. Examples of a method of mixing and dispersing in an alicyclic epoxy resin after mixing into a powder, and a method of directly mixing and dehydrating a rubber particle emulsion and an alicyclic epoxy resin can be given.

  The amount of the rubber particle dispersion curable epoxy resin (A) used is preferably about 30 to 100% by weight based on the total amount of epoxy group-containing compounds contained in the resin composition for encapsulating an optical semiconductor. However, it is preferably about 50 to 100% by weight. When the amount of the rubber particle dispersion curable epoxy resin (A) used is less than 30% by weight based on the total amount of the epoxy group-containing compound, the crack resistance of the resulting cured product tends to be lowered.

[Other epoxy compounds]
The resin composition for encapsulating an optical semiconductor of the present invention may contain an epoxy resin other than the rubber particle dispersion curable epoxy resin (A). Examples of such epoxy resins include alicyclic epoxy resins that do not contain rubber particles and epoxy resins other than alicyclic epoxy resins.

  As an alicyclic epoxy resin which does not contain a rubber particle, the alicyclic epoxy resin represented by said Formula (1) can be mentioned, for example. These can be used alone or in combination of two or more. As usage-amount of the alicyclic epoxy resin which does not contain a rubber particle, it is 0-60 weight% (for example, 3-60) with respect to the total amount of the epoxy-group containing compound contained in the resin composition for optical semiconductor sealing, for example. % By weight), preferably 0 to 45% by weight (for example, 5 to 45% by weight).

  Examples of the epoxy resin other than the alicyclic epoxy resin include a glycidyl ether epoxy compound having no aromatic ring, a glycidyl ether epoxy compound having an aromatic ring (bisphenol A type, bisphenol F type, etc.), and a glycidyl ester epoxy compound. And glycidylamine-based epoxy compounds. These can be used alone or in combination of two or more. Of these, glycidyl ether epoxy compounds having no aromatic ring are preferred. By blending a glycidyl ether epoxy compound having no aromatic ring, crack resistance may be further improved without impairing high heat resistance and light resistance.

  The glycidyl ether-based epoxy compound having no aromatic ring includes an aliphatic glycidyl ether-based epoxy compound [with a viscosity exceeding 200 mPa · s at room temperature (25 ° C.)] and an aromatic glycidyl ether-based epoxy compound. Compound. Examples of glycidyl ether type epoxy compounds having no aromatic ring include, for example, trade names “EPICLON 703”, “EPICLON 707”, “EPICLON 720”, “EPICLON 725” (manufactured by DIC Corporation), trade names “YH-300”, “YH-”. 315 ”,“ YH-324 ”,“ PG-202 ”,“ PG-207 ”,“ Santoto ST-3000 ”(manufactured by Toto Kasei Co., Ltd.), trade names“ Likaresin DME-100 ”,“ Likaresin HBE-100 ” ”(Manufactured by Shin Nippon Rika Co., Ltd.), trade names“ Denacol EX-212 ”,“ Denacol EX-321 ”(manufactured by Nagase ChemteX Corp.), trade names“ YX8000 ”,“ YX8034 ”(Japan Epoxy Resin ( Commercially available products such as those manufactured by the company) can be suitably used. As the usage-amount of the glycidyl ether type epoxy compound which does not have an aromatic ring, it is 0-60 weight% (for example, 3-60) with respect to the total amount of the epoxy-group containing compound contained in the resin composition for optical semiconductor sealing, for example. % By weight), preferably 0 to 45% by weight (for example, 5 to 45% by weight).

  As an epoxy resin mix | blended with the resin composition for optical semiconductor sealing of this invention, although a liquid thing is preferable at normal temperature (25 degreeC), even if it was the epoxy compound which exhibits solid at normal temperature (25 degreeC), it mix | blended. It may be contained as long as it is liquid later. Examples of the epoxy compound that exhibits a solid at room temperature (25 ° C.) include solid bisphenol-type epoxy compounds, novolac-type epoxy compounds, glycidyl esters, triglycidyl isocyanurate, and 2,2-bis (hydroxymethyl) -1-butanol. Examples include 1,2-epoxy-4- (2-oxiranyl) cyclosoxane adduct (trade name “EHPE3150”, manufactured by Daicel Chemical Industries, Ltd.). These epoxy compounds can be used individually or in combination of 2 or more types.

  Furthermore, a reaction diluent can also be used for the resin composition for optical semiconductor encapsulation of the present invention. The viscosity can be adjusted by using a reactive diluent. As the reactive diluent, an aliphatic polyglycidyl ether compound (such as alkylene glycol diglycidyl ether) having a viscosity at room temperature (25 ° C.) of 200 mPa · s or less (preferably 100 mPa · s or less) can be suitably used. . Examples of the aliphatic polyglycidyl ether include cyclohexanedimethanol diglycidyl ether, cyclohexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and polypropylene glycol. A diglycidyl ether etc. can be mentioned. An oxetane compound or a vinyl ether compound having cationic curability can also be used as a reactive diluent.

  The amount of the reactive diluent used can be adjusted as appropriate. For example, it is 30 parts by weight or less, preferably 25 parts by weight or less (for example, 100 parts by weight of the rubber particle dispersion curable epoxy resin (A) (for example, 5 to 25 parts by weight). If the amount of the reactive diluent used exceeds 30 parts by weight, it tends to be difficult to obtain desired performance such as crack resistance.

[Polyfunctional thiol (B)]
The polyfunctional thiol (B) is preferably a 2-6 functional thiol (thioalcohol having 2-6 mercapto groups in the molecule). The polyfunctional thiol is preferably in a liquid state at normal temperature (25 ° C.). These polyfunctional thiols may be primary, secondary, or a mixture thereof. Moreover, even if it is solid thiol, as long as it melt | dissolves in an epoxy resin or hardening | curing agents (an acid anhydride etc.), it does not matter.

  As typical examples of polyfunctional thiols, compounds represented by the following formulas (2a) to (2h) can be given.

  Examples of commercially available first-class polyfunctional thiols include “EGMP-4”, “TMMP”, “TEMPIC”, “PEMP”, “DPMP” (manufactured by Sakai Chemical Industry Co., Ltd.). Commercially available secondary polyfunctional thiols include trade names “BD-1”, “NR-1”, “PE-1” (above, Showen Denko Co., Ltd., Karenz MT (registered trademark) series). and so on.

  As usage-amount of polyfunctional thiol (B), it is 1-50 weight part with respect to 100 weight part of total amounts of the epoxy-group containing compound contained in the resin composition for optical semiconductor sealing, Preferably it is 3-40 weight. Part, more preferably about 5 to 25 parts by weight. If the amount of the polyfunctional thiol (B) used is less than 1 part by weight, the crack resistance of the resulting cured product tends to decrease, and if it exceeds 50 parts by weight, the viscosity increases too much, and the pot life is increased (pot life). It tends to be shorter.

[Curing agent (C)]
The curing agent (C) has a function of curing the epoxy resin. As the curing agent (C) in the present invention, a conventional curing agent can be used as a curing agent for an epoxy resin, and an acid anhydride is particularly preferable. In particular, the curing agent (C) in the present invention is preferably an acid anhydride which is liquid at 25 ° C., for example, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenyl succinic anhydride, methylendomethylenetetrahydroanhydride. And phthalic acid. In addition, solid acid anhydrides at room temperature (25 ° C.) such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, etc., are acid anhydrides that are liquid at room temperature (25 ° C.). It can be used as the curing agent (C) in the present invention by dissolving in a product or the like to form a liquid mixture.

  In the present invention, as the curing agent (C), commercially available products such as trade name “Rikacid MH-700” (manufactured by Shin Nippon Rika Co., Ltd.) and trade name “HN-5500” (manufactured by Hitachi Chemical Co., Ltd.) are used. It can also be used.

  As a usage-amount of a hardening | curing agent (C), 50-150 weight part with respect to 100 weight part of total amounts of the epoxy-group containing compound contained in the resin composition for optical semiconductor sealing, for example, Preferably 52-145 weight Part, more preferably about 55 to 140 parts by weight. More specifically, it is 0.5 to 1.5 equivalents (acid anhydride equivalents) per 1 equivalent of epoxy groups in all epoxy resins (epoxy compounds) contained in the resin composition for optical semiconductor encapsulation. It is preferable to use in proportions. When the amount of the curing agent (C) used is less than 50 parts by weight, the effect becomes insufficient and the toughness of the cured product tends to be reduced, while the amount of the curing agent (C) used exceeds 150 parts by weight. When the cured product is colored, the hue may deteriorate.

[Curing accelerator (D)]
The curing accelerator (D) is a compound having a function of accelerating the curing rate when the epoxy resin is cured by the curing agent (C). As the curing accelerator (D) in the present invention, a commonly used conventional curing accelerator can be used. For example, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), And salts thereof (eg, phenol salt, octylate, p-toluenesulfonate, formate, tetraphenylborate salt); 1,5-diazabicyclo [4.3.0] nonene-5 (DBN), and its Salts (eg, phosphonium salts, sulfonium salts, quaternary ammonium salts, iodonium salts); tertiary amines such as benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N-dimethylcyclohexylamine; Imidazoles such as 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole; Phosphines such as acid esters and triphenylphosphine; Phosphonium compounds such as tetraphenylphosphonium tetra (p-tolyl) borate; Organometallic salts such as tin octylate and zinc octylate; Metal chelates (aluminum trisacetylacetonate, aluminum And a chelate compound of a metal such as aluminum trisacetoacetate, such as aluminum or titanium, and an acetoacetate ester or diketone). These can be used alone or in admixture of two or more.

  Among these, as the curing accelerator (D), a diazabicycloundecene-based curing accelerator (DBU and its salt) is preferable. From the viewpoint of improving the hue of the cured product, it is preferable to use 50% by weight or more, particularly 70% by weight or more of the total curing accelerator used as the diazabicycloundecene curing accelerator.

  In the present invention, as the curing accelerator (D), trade names “U-CAT SA 506”, “U-CAT SA 102”, “U-CAT 5003”, “U-CAT 18X”, “12XD” (any , San Apro Co., Ltd.), trade names "TPP-K", "TPP-MK" (both made by Hokuko Chemical Co., Ltd.), trade names "PX-4ET" (made by Nippon Chemical Industry Co., Ltd.), etc. It is also possible to use commercially available products.

  As the usage-amount of a hardening accelerator (D), 0.05-5 weight part with respect to 100 weight part of total amounts of the epoxy-group containing compound contained in the resin composition for optical semiconductor sealing, for example, Preferably it is 0. 0.1 to 3 parts by weight, particularly preferably 0.2 to 3 parts by weight, and most preferably about 0.25 to 2.5 parts by weight. When the amount of the curing accelerator (D) used is less than 0.05 parts by weight, the curing acceleration effect may be insufficient. On the other hand, when the amount of the curing accelerator (D) used is more than 5 parts by weight, The cured product may be colored to deteriorate the hue.

[Thermosetting catalyst (E)]
The thermosetting catalyst (E) in the present invention has a function of initiating polymerization of an epoxy resin (epoxy compound). The thermosetting catalyst (E) in the present invention is preferably a cationic polymerization initiator that generates cationic species by heat treatment and initiates polymerization of the rubber particle dispersion-curable epoxy resin (A).

  Examples of the cationic polymerization initiator that generates cationic species by performing heat treatment include aryldiazonium salts, aryliodonium salts, arylsulfonium salts, allene-ion complexes, etc., and trade name “PP-33”. “CP-66”, “CP-77” (manufactured by ADEKA Corporation), trade name “FC-509” (manufactured by 3M Corporation), trade name “UVE1014” (manufactured by GE Corporation) , Trade name "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L", "Sun-Aid SI-110L" (manufactured by Sanshin Chemical Industry Co., Ltd.), trade name "CG-24-61" Commercial products such as (manufactured by Ciba Japan Co., Ltd.) can be suitably used. Further, a chelate compound of a metal such as aluminum or titanium and a acetoacetate ester or diketone compound and a silanol such as triphenylsilanol, or a chelate compound of a metal such as aluminum or titanium and acetoacetate ester or diketone It may be a compound with phenols such as bisphenol S.

  As the usage-amount of a thermosetting catalyst (E), 0.01-15 weight part with respect to 100 weight part of total amounts of the epoxy group containing compound contained in the resin composition for optical semiconductor sealing, for example, Preferably it is 0. 0.01 to 12 parts by weight, particularly preferably 0.05 to 10 parts by weight, and most preferably about 0.1 to 10 parts by weight. By using within this range, a cured product having excellent heat resistance, transparency, and weather resistance can be obtained.

[Other ingredients]
You may mix | blend another component with the resin composition for optical semiconductor sealing of this invention as needed. Examples of such other components include polyol compounds (excluding polyether polyol) that are liquid at 25 ° C.

  Examples of the polyol compound that exhibits a liquid state at 25 ° C. include polyester polyol and polycarbonate polyol.

  Examples of the polyester polyol include trade names “Placcel 205”, “Placcel 205H”, “Placcel 205U”, “Placcel 205BA”, “Placcel 208”, “Placcel 210”, “Placcel 210CP”, “Placcel 210BA”, “ Plaxel 212, Plaxel 212CP, Plaxel 220, Plaxel 220CPB, Plaxel 220NP1, Plaxel 220BA, Plaxel 220ED, Plaxel 220EB, Plaxel 220EC, Plaxel 230, Plaxel 230CP, Plaxel 240, Plaxel 240CP, Plaxel 210N, Plaxel 220N, Plaxel L205AL, Plaxel L208AL “Plaxel L212AL”, “Plaxel L220AL”, “Plaxel L230AL”, “Plaxel 305”, “Plaxel 308”, “Plaxel 312”, “Plaxel L312AL”, “Plaxel 320”, “Plaxel L320AL”, “Plaxel L330AL”, Commercial products such as “Placcel 410”, “Placcel 410D”, “Placcel 610”, “Placcel P3403”, and “Placcel CDE9P” (manufactured by Daicel Chemical Industries, Ltd.) can be used.

  As the polycarbonate polyol, for example, trade names “Placcel CD205PL”, “Placcel CD205HL”, “Placcel CD210PL”, “Placcel CD210HL”, “Placcel CD220PL”, “Placcel CD220HL” (manufactured by Daicel Chemical Industries, Ltd.), trade names “UH-CARB50”, “UH-CARB100”, “UH-CARB300”, “UH-CARB90 (1/3)”, “UH-CARB90 (1/1)”, “UC-CARB100” (Ube Industries, Ltd.) )), Trade names such as "PCDL T4671", "PCDL T4672", "PCDL T5650J", "PCDL T5651", "PCDL T5652" (manufactured by Asahi Kasei Chemicals Corporation) can be used.

  As a usage-amount of the polyol compound which exhibits a liquid state at 25 degreeC, for example, about 0-50 weight part (for example, 3-50 weight part) with respect to 100 weight part of rubber particle dispersion-curable epoxy resins (A), Preferably 0 to 40 parts by weight (for example, 10 to 40 parts by weight).

  In addition to the above, the resin composition for encapsulating an optical semiconductor of the present invention may contain various additives within a range that does not impair the effects of the present invention.

  For example, when a compound having a hydroxyl group (polyol compound or the like) such as ethylene glycol, neopentyl glycol, diethylene glycol, propylene glycol, or glycerin is used as the additive, the reaction can be allowed to proceed slowly. In addition, as long as the viscosity and transparency are not impaired, silicone-based and fluorine-based antifoaming agents, leveling agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, surfactants, fillers, Conventional additives such as a flame retardant, a colorant, an antioxidant, an ultraviolet absorber, an ion adsorbent, a pigment, and a release agent can be used. As the compounding quantity of these various additives, it is 5 weight% or less, respectively with respect to the resin composition for optical semiconductor sealing, for example. The total amount of these additives is, for example, 10% by weight or less, preferably 5% by weight or less, based on the total amount of the resin composition for optical semiconductor encapsulation.

[Production of resin composition for optical semiconductor encapsulation]
In order to produce the optical semiconductor sealing resin composition of the present invention, a method usually used for producing a curable resin composition can be used. For example, a predetermined amount of rubber particle dispersion curable epoxy resin (A), polyfunctional thiol (B), curing agent (C) and curing accelerator (D), or rubber particle dispersion curable epoxy resin (A), multiple Add other components (other epoxy compounds, additives, etc.) to the functional thiol (B) and thermosetting catalyst (E) as necessary, and stir and mix while excluding bubbles under vacuum heating. It is prepared by. The temperature at the time of stirring and mixing is usually preferably set to 10 to 60 ° C. If the set temperature at the time of preparation is less than 10 ° C., the viscosity is too high to make uniform stirring and mixing operations difficult. Conversely, if the temperature at the time of preparation exceeds 60 ° C., a curing reaction occurs, and a normal optical semiconductor. Since the sealing resin composition cannot be obtained, it is not preferable. When stirring and mixing, a general-purpose device such as a kneader or dissolver may be used, for example, by stirring and mixing for about 10 minutes.

  For the polyfunctional thiol (B), curing agent (C), curing accelerator (D), thermosetting catalyst (E) and other components (other epoxy compounds, additives, etc.), rubber particles produced in advance Although it can also add and mix | blend with a dispersion-curable epoxy resin (A), some or all of them can also be added and mix | blended at the time of manufacture of a rubber particle dispersion-curable epoxy resin (A).

  The resin composition for encapsulating an optical semiconductor of the present invention preferably exhibits a liquid state at normal temperature (25 ° C.) from the viewpoint of processability when encapsulating an optical semiconductor element. The viscosity (25 ° C.) of the resin composition for sealing an optical semiconductor is preferably 20000 mPa · s or less (for example, 200 to 20000 mPa · s), more preferably 15000 mPa · s or less (for example, 200 to 15000 mPa · s). It is.

  The resin composition for encapsulating an optical semiconductor of the present invention is cured to form a cured product that can exhibit excellent crack resistance while maintaining high heat resistance and transparency. Therefore, it can be suitably used for sealing an optical semiconductor element.

[Hardened product of resin composition for optical semiconductor encapsulation]
A cured product is obtained by heating the resin composition for optical semiconductor encapsulation.

  As glass transition temperature of the hardened | cured material of the resin composition for optical semiconductor sealing of this invention, 110-210 degreeC is preferable, More preferably, it is 130-200 degreeC.

  The cured product of the resin composition for encapsulating an optical semiconductor of the present invention is preferably optically homogeneous. Optically homogeneous means, for example, that the refractive index is uniform in the cured resin, and can be determined by high light transmittance or light scattering, as will be described later. is there. Optical homogeneity is achieved, for example, by the degree of curing of the cured resin being uniform in the cured product.

  The cured product of the resin composition for encapsulating an optical semiconductor of the present invention preferably has excellent transparency, and the light transmittance at a wavelength of 450 nm in a cured product having a thickness of 3 mm is preferably 80 T% or more, more preferably. It is 85 T% or more. When the transmittance is lower than the above range, when used as a sealant for an optical semiconductor element, the light emission efficiency may be lowered and the performance may be lowered.

[Optical semiconductor device]
In the optical semiconductor device of the present invention, the optical semiconductor element is sealed with the resin composition for sealing an optical semiconductor. The method for sealing the optical semiconductor element is not particularly limited, and a well-known and commonly used method can be used. Examples thereof include a potting method, a casting method, and a printing method.

  For example, the optical semiconductor element can be sealed by injecting the resin composition for optical semiconductor sealing prepared by the above-described method into a predetermined mold and heat curing under predetermined conditions. Thereby, the optical semiconductor device in which the optical semiconductor element is sealed with the optical semiconductor sealing resin composition is obtained. The resin composition for encapsulating an optical semiconductor of the present invention has a temperature of 100 to 200 ° C., preferably 100 to 190 ° C., more preferably 100 to 180 ° C., and a curing time of 30 to 600 minutes, preferably 45 to 540. Minutes, more preferably 60 to 480 minutes. When the curing temperature and the curing time are lower than the lower limit value in the above range, curing is insufficient. On the contrary, when the curing temperature and the curing time are higher than the upper limit value in the above range, the resin component may be decomposed. Although the curing conditions depend on various conditions, when the curing temperature is high, the curing time is short, and when the curing temperature is low, the curing time is long and can be adjusted as appropriate. Further, the curing can be performed by dividing the curing temperature into two or more stages.

  In the optical semiconductor device of the present invention, since the optical semiconductor element is sealed with the resin composition for sealing an optical semiconductor of the present invention, it is possible to maintain excellent light intensity over a long period of time. Therefore, long and high performance can be maintained, and high reliability can be obtained as a long-life optical semiconductor device.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples. In addition, the measurement of the average particle diameter of the rubber particles, the maximum particle diameter, the measurement of the viscosity of the rubber particle dispersion curable epoxy resin obtained in the production example, the resin composition for optical semiconductor encapsulation obtained in the examples and comparative examples And the evaluation test of hardened | cured material was done with the following method.

(Average particle diameter of rubber particles, maximum particle diameter)
The average particle size and the maximum particle size of the rubber particles were analyzed using a particle size analyzer (“Nanotrac ^™ ” type UPA-EX150) manufactured by Nikkiso Co., Ltd., which uses a dynamic light scattering method as a measurement principle. As a sample, 1 part by weight of rubber particle dispersion curable epoxy resin was dissolved in 20 parts by weight of tetrahydrofuran (THF), and the rubber particles were dispersed and measured. In the obtained particle size distribution measurement results, the cumulative average diameter, which is the particle diameter when the cumulative curve becomes 50%, was taken as the average particle diameter of the rubber particles. The largest particle size (μm) at the time when the frequency (%) of the particle size distribution measurement result exceeded 0.00 was defined as the maximum particle size.

(viscosity)
The viscosity of the rubber particle-dispersed curable epoxy resin obtained in Production Example [5 parts by weight of rubber particles dispersed in 100 parts by weight of Celoxide 2021P (manufactured by Daicel Chemical Industries)] is a digital viscometer (trade name) Viscosity at 25 ° C. was measured using “DVU-EII type” (manufactured by Tokimec Co., Ltd.).

(Refractive index difference)
Each cured product obtained in Examples and Comparative Examples was cut into 20 mm length × 6 mm width × 1 mm thickness to obtain test pieces. As an intermediate solution, monobromonaphthalene was sandwiched between the prism and the test piece and adhered. The refractive index at 20 ° C. and sodium D line was measured with a multi-wavelength Abbe refractometer (trade name “DR-M2”) manufactured by Atago Co., Ltd. The absolute value of the difference between the refractive index of the rubber particles and the measured refractive index of the cured product was taken as the refractive index difference.
The refractive index of the rubber particles is as follows: 1 g of rubber particles is cast into a mold and compression molded at 210 ° C. and 4 MPa to obtain a flat plate having a thickness of 1 mm. From the obtained flat plate, a test piece of 20 mm length × 6 mm width is obtained. The refractive index at 20 ° C. and sodium D line was measured in the same manner as described above.

(Heat-resistant)
Each of the optical semiconductor encapsulating resin compositions obtained in Examples and Comparative Examples was thermally cured at 110 ° C. for 2 hours + 150 ° C. for 3 hours to prepare a test piece (length 10 mm, width 5 mm, thickness 5 mm). did. About this test piece, the glass transition temperature (Tg, (degreeC)) was measured using the thermomechanical measurement apparatus (TMA) (The Seiko Instruments company make, brand name "TMA SS6100"), and it was set as the heat resistant parameter | index.

(transparency)
Thermosetting was performed under the same conditions as in the heat resistance test to produce a cured resin product having a thickness of 3 mm, which was used as a test piece. About this test piece, the light transmittance [transmittance (T%)] at wavelengths of 400 nm and 380 nm was measured using a spectrophotometer [manufactured by Shimadzu Corporation, trade name “UV-2450”]. did.

(Crack resistance test)
Using each resin composition for encapsulating optical semiconductors obtained in Examples and Comparative Examples, an LED framed on an LED frame under the same conditions as those for producing the heat-resistant test piece, a heat cycle tester ( A product name “TSE-11” manufactured by ESPEC CORP. Was used, and a crack resistance test in a heat cycle test was performed with 105 ° C. for 30 minutes and −45 ° C. for 30 minutes as one cycle. In addition, after making 10 samples for each sample, it was confirmed that all samples had no cracks before the test. Thereafter, the number of cracked samples every 100 cycles and 500 cycles was confirmed with a 20-fold magnifier using the heat cycle tester. The cracks were generated from the edge of the reflector. The case where the number of cracks was 0 to 2 was evaluated as ◯, the case of 3 to 6 as Δ, and the case of 7 or more as ×.

(Light resistance test)
Using the test piece for evaluating the transparency, a light resistance test for 500 hours was performed with a light resistance tester (manufactured by Daipla Intes) at 23 ° C. After the test, the transmittance at 450 nm was compared. Light resistance was determined by the following formula.
[1-((transmittance before test−transmittance after test) / transmittance before test)] × 100

Production Example 1
A 1 L polymerization vessel equipped with a reflux condenser was charged with 500 g of ion exchange water and 0.68 g of sodium dioctyl succinate, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream. Here, a monomer mixture consisting of 9.5 g of butyl acrylate, 2.57 g of styrene, and 0.39 g of divinylbenzene corresponding to about 5% by weight of the amount required to form the core portion is collectively collected. After adding and emulsifying with stirring for 20 minutes, 9.5 mg of potassium peroxodisulfate is added, stirring for 1 hour for the initial seed polymerization, followed by addition of 180.5 mg of potassium peroxodisulfate, Stir for 5 minutes. Here, 180.5 g of the remaining amount (about 95% by weight) of butyl acrylate, 48.89 g of styrene, 7.33 g of divinylbenzene and 0.95 g of sodium dioctyl succinate are added to form the core part. The dissolved monomer mixture was continuously added over 2 hours to perform the second seed polymerization, and then aged for 1 hour to obtain a core part.

  Next, 60 mg of potassium peroxodisulfate was added and stirred for 5 minutes. To this, a solution obtained by dissolving 0.3 g of sodium dioctyl succinate in 60 g of methyl methacrylate, 1.5 g of acrylic acid, and 0.3 g of allyl methacrylate was added. The monomer mixture was continuously added over 30 minutes to perform seed polymerization, and then aged for 1 hour to form a shell layer covering the core portion.

  Next, the mixture was cooled to room temperature (25 ° C.) and filtered through a plastic mesh having an opening of 120 μm to obtain a latex containing particles having a core-shell structure. The obtained latex was frozen at −30 ° C., dehydrated and washed with a suction filter, and then blown and dried at 60 ° C. overnight to obtain rubber particles (1). The obtained rubber particles (1) had an average particle size of 254 nm, a maximum particle size of 486 nm, and a refractive index of 1.500.

  Using a dissolver (1000 rpm, 60 minutes) in a state heated to 60 ° C. in a nitrogen stream, 5 parts by weight of the obtained rubber particles (1) were added to 100 parts of Celoxide 2021P (manufactured by Daicel Chemical Industries, Ltd.). It was dispersed in a part and vacuum degassed to obtain a rubber particle dispersion curable epoxy resin (A-1) (viscosity at 25 ° C .: 559 mPa · s).

Production Example 2
Rubber particles (2) were obtained in the same manner as in Production Example 1 except that 2.7 g of 2-hydroxyethyl methacrylate was used instead of 1.5 g of acrylic acid. The obtained rubber particles (2) had an average particle size of 261 nm, a maximum particle size of 578 nm, and a refractive index of 1.500.
Further, in the same manner as in Production Example 1, a rubber particle dispersion curable epoxy resin (A-2) (viscosity at 25 ° C .: 512 mPa · s) was obtained.

Production Example 3
A 1 L polymerization vessel equipped with a reflux condenser was charged with 500 g of ion-exchanged water and 1.3 g of sodium dioctyl succinate and heated to 80 ° C. while stirring under a nitrogen stream. Here, a monomer mixture consisting of 9.5 g of butyl acrylate, 2.57 g of styrene, and 0.39 g of divinylbenzene corresponding to about 5% by weight of the amount necessary to form the core portion is collectively collected. After adding and emulsifying with stirring for 20 minutes, 12 mg of potassium peroxodisulfate was added and stirred for 1 hour to perform the initial seed polymerization, followed by addition of 228 mg of potassium peroxodisulfate and stirring for 5 minutes. . Here, 180.5 g of the remaining amount of butyl acrylate necessary for forming the core portion (about 95% by weight), 48.89 g of styrene, 7.33 g of divinylbenzene, 1.2 g of sodium dioctyl succinate The dissolved monomer mixture was continuously added over 2 hours to perform the second seed polymerization, and then aged for 1 hour to obtain a core portion.

Next, rubber particles (3) were obtained in the same manner as in Production Example 1 except that the amount of acrylic acid used was changed from 1.5 g to 2.0 g. The rubber particles (3) obtained had an average particle size of 108 nm, a maximum particle size of 289 nm, and a refractive index of 1.500.
Further, in the same manner as in Production Example 1, a rubber particle dispersion curable epoxy resin (A-3) (viscosity at 25 ° C .: 1036 mPa · s) was obtained.

Examples 1-6, Comparative Examples 1-2
In accordance with the formulation shown in Table 1 (unit: parts by weight), each component is uniformly mixed using a self-revolving stirrer (trade name “Awatori Nerita AR-250”, manufactured by Shinky Corporation). (2000 rpm, room temperature, 5 minutes) was defoamed to obtain an optical semiconductor sealing resin composition. The obtained resin composition for optical semiconductor encapsulation was cast into a mold and heated at 110 ° C. for 2 hours and at 150 ° C. for 3 hours to obtain a cured product.

  The said evaluation test was done about the resin composition for optical semiconductor sealing and hardened | cured material which were obtained by each Example and the comparative example. The results are shown in Table 1. The meanings of the symbols in the table are as follows.

(Epoxy resin)
HBE-100: Epoxy resin mainly composed of diglycidyl ether of hydrogenated bisphenol A, trade name “Rikaresin HBE-100”, manufactured by Shin Nippon Rika Co., Ltd. YX8000: diglycidyl ether of hydrogenated bisphenol A as the main component Epoxy resin, trade name “Epicoat YX8000”, manufactured by Japan Epoxy Resins Co., Ltd. CEL-2081: adduct of 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate and ε-caprolactone, Daicel Chemical Made by Kogyo Co., Ltd.

(Multifunctional thiol)
PEMP: pentaerythritol tetrakis-3-mercaptopropionate, manufactured by Sakai Chemical Industry Co., Ltd. TEMPIC: tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, manufactured by Sakai Chemical Industry Co., Ltd. PE-1: Pentaerythritol tetrakis (3-mercaptobutyrate), manufactured by Showa Denko KK, trade name “Karenz MT (registered trademark) PE1”

(Curing agent)
Rikacid MH-700: Methylhexahydrophthalic anhydride (manufactured by Shin Nippon Rika Co., Ltd., trade name “Rikacid MH-700”)

(Curing accelerator)
U-CAT SA-506: DBU-p-toluenesulfonate, manufactured by San Apro Co., Ltd., trade name “U-CAT SA-506”

(Additive)
Ethylene glycol: Wako Pure Chemical Industries, Ltd.

Claims (6)

  It is composed of a polymer having (meth) acrylic acid ester as an essential monomer component, has a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with an epoxy group on the surface, an average particle size of 10 nm to 500 nm, and a maximum particle size Particle dispersion sclerosis | hardenability which disperse | distributed to the alicyclic epoxy resin the rubber particle whose refractive index difference with respect to the hardened | cured material of the said resin composition for optical semiconductor sealing is 50 nm-1000 nm and less than +/- 0.02 The resin composition for optical semiconductor sealing containing an epoxy resin (A), a polyfunctional thiol (B), a hardening | curing agent (C), and a hardening accelerator (D).   It is composed of a polymer having (meth) acrylic acid ester as an essential monomer component, has a hydroxyl group and / or a carboxyl group as a functional group capable of reacting with an epoxy group on the surface, an average particle size of 10 nm to 500 nm, and a maximum particle size Particle dispersion sclerosis | hardenability which disperse | distributed to the alicyclic epoxy resin the rubber particle whose refractive index difference with respect to the hardened | cured material of the said resin composition for optical semiconductor sealing is 50 nm-1000 nm and less than +/- 0.02 The resin composition for optical semiconductor sealing containing an epoxy resin (A), a polyfunctional thiol (B), and a thermosetting catalyst (E).   The resin composition for optical semiconductor encapsulation according to claim 1 or 2, wherein the polyfunctional thiol (B) is liquid at 25 ° C.   The resin composition for optical semiconductor encapsulation according to claim 1, wherein the curing agent (C) is a liquid acid anhydride at 25 ° C.   Hardened | cured material obtained by hardening | curing the resin composition for optical semiconductor sealing in any one of Claims 1-4.   An optical semiconductor device in which an optical semiconductor element is sealed with the optical semiconductor sealing resin composition according to claim 1.