JP2009249569A - Epoxy resin composition for optical element sealing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition for an optical element sealing material, excellent in heat resistance, light resistance, hygroscopicity, adhesiveness and colorless transparency, providing a cured object having sufficient strength, and, in particular, useful as a sealing material of an LED emitting light of short wavelengths. <P>SOLUTION: This epoxy resin composition for the optical element sealing material contains (A) a component: an alicyclic epoxy resin composition, (B) a component: a rubber-like polymer particle, and (C) a component: one kind, two kinds or more of curing agents selected from the group comprising acid anhydrides, modified acid anhydrides, and cationic polymerization initiators, a content of the (A) component is 100-50 mass% with respect to total epoxy resin component, a content of the (B) component is 1-50 mass% with respect to the total epoxy resin component, and light beam transmittance is 70% or more at 400 nm of wavelength in the cured object having 2±0.2 mm of thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an epoxy resin composition for a light emitting device sealing material, in which an alicyclic epoxy resin, rubber-like polymer particles, and a curing agent are blended.
The cured product of the epoxy resin composition for optical element sealing material of the present invention is excellent in heat resistance, moisture resistance, light resistance, adhesion, and transparency, and has no brittleness problem. It is useful as an encapsulant for LEDs that emit light with a short wavelength, especially for applications related to optical semiconductors.

  Epoxy resins are excellent in heat resistance, adhesion, water resistance, mechanical strength, electrical properties, etc., so they are used in various fields such as adhesives, paints, materials for civil engineering and construction, insulating materials for electrical and electronic parts, etc. in use. As the normal temperature or heat curable epoxy resin, aromatic epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, phenol or cresol novolac type epoxy resin are generally used.

  In recent years, many light emitting devices such as optical semiconductors (LEDs) that have been put to practical use in various display boards, image reading light sources, traffic signals, large display units, and the like are manufactured by resin sealing. The sealing resin used here generally contains the above aromatic epoxy resin and an alicyclic acid anhydride as a curing agent.

On the other hand, due to the dramatic progress of today's LEDs, higher output and shorter wavelengths of LED elements are rapidly becoming a reality. Particularly, LEDs using a periodic table group III nitride semiconductor are shorter. Light emission with a wavelength and high output is possible.
However, when an LED element using a nitride semiconductor is sealed with the above-described aromatic epoxy resin, the aromatic ring of the epoxy resin absorbs light of a short wavelength, so that the resin sealed over time deteriorates. There arises a problem that the emission luminance is remarkably lowered due to yellowing.

Then, LED sealed using the alicyclic epoxy resin obtained by oxidizing cyclic olefin represented by 3, 4- epoxy cyclohexyl methyl-3 ', 4'-epoxy cyclohexane carboxylate is proposed. (Patent Document 1, Patent Document 2).
However, the cured resin encapsulated with the above alicyclic epoxy resin is very brittle, easily cracked by the thermal cycle, and extremely poor in moisture resistance, so it is not suitable for applications that require long-term reliability. Met.

  Therefore, studies for imparting flexibility to epoxy resins are being actively conducted. Among them, there is a method of improving flexibility by blending an elastomer such as a carboxyl group-terminated butadiene / acrylonitrile copolymer (CTBN) or a thermoplastic elastic body into an epoxy resin. Also known is a method of adding a flexible epoxy resin having a flexible skeleton in the molecule such as diglycidyl ester of dimer acid or diglycidyl ether of polypropylene glycol.

However, the method of adding a thermoplastic elastic body is improved in crack resistance, but the effect of improving moisture resistance is insufficient, and is unsuitable for applications requiring long-term reliability characteristics.
In addition, the method of adding a flexible epoxy resin is simply to soften the cured product, the heat resistance of the cured product is reduced, and the resin sealed over time is deteriorated. The problem of deteriorating will occur.

Therefore, an LED sealed with an alicyclic epoxy resin obtained by oxidizing a cyclic olefin and a hydrogenated epoxy resin typified by a hydrogenated bisphenol A type epoxy resin has been proposed (Patent Document 3, Patent). Document 4 and Patent document 5).
However, in a cured resin using a combination of an alicyclic epoxy resin obtained by oxidizing the above cyclic olefin and an alicyclic epoxy resin obtained by hydrogenating an aromatic epoxy resin such as a bisphenol A type epoxy resin, moisture resistance is Although improved, the effect of improving brittleness is insufficient, and it is insufficient in terms of suppressing crack fracture caused by the thermal cycle.

Thus, a colorless and transparent cured product is obtained, and the LED encapsulant that is excellent in heat resistance, ultraviolet resistance, moisture resistance (moisture absorption resistance) and adhesion, and improves the brittleness of the epoxy cured product. A solution to the fundamental problem was awaited.
JP-A-9-213997 JP 2000-196151 A JP 2000-143939 A JP-A-11-199645 JP 2001-19742 A

  The present invention solves the problems of heat resistance and brittleness of conventional epoxy cured products, and provides a cured product having excellent heat resistance, moisture resistance, light resistance, adhesion, colorless transparency and sufficient strength. It is an object of the present invention to provide an epoxy resin composition for an optical element sealing material that is particularly useful as a sealing material for LEDs that emit light having a short wavelength.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have obtained an epoxy resin composition containing an alicyclic epoxy resin, rubber-like polymer particles, and a specific curing agent. The inventors have found that the object can be achieved and have completed the present invention.
That is, the present invention includes the following inventions.

[1] The following (A) component, (B) component, and (C) component are contained, the content of (A) component is 100-50 mass% with respect to all the epoxy resin components, An optical element seal characterized in that the content is 1 to 50% by mass with respect to all epoxy resin components, and the light transmittance at a wavelength of 400 nm of a cured product having a thickness of 2 mm ± 0.2 mm is 70% or more. Epoxy resin composition for fastening materials.
(A) component; alicyclic epoxy resin (B) component; rubber-like polymer particles
Component (C): one or more curing agents selected from the group consisting of acid anhydrides, modified acid anhydrides, and cationic polymerization initiators

[2] At least one epoxy selected from the group consisting of an epoxy resin obtained by epoxidizing a cyclic olefin and an epoxy resin obtained by hydrogenating an aromatic epoxy resin, wherein the alicyclic epoxy resin of component (A) is epoxidized The epoxy resin composition for optical element sealing materials according to [1], which is a resin.

[3] The alicyclic epoxy resin of component (A) is 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, an epoxy resin obtained by hydrogenating a bisphenol A type epoxy resin, bisphenol F It is 1 type, or 2 or more types chosen from the group which consists of the epoxy resin obtained by hydrogenating a type epoxy resin, and the epoxy resin obtained by hydrogenating a biphenol type epoxy resin, It is characterized by the above-mentioned. Epoxy resin composition for optical element sealing material.

[4] The rubber-like polymer particles of the component (B) graft 5 to 50% by mass of the shell layer of the following (Ba-2) with respect to 50 to 95% by mass of the rubber particle core of the following (Ba-1). The epoxy resin composition for optical element sealing materials according to any one of [1] to [3], which is rubbery polymer particles (Ba) obtained by polymerization.
(Ba-1): 50% by mass or more of at least one monomer selected from the group consisting of a diene monomer and a (meth) acrylate monomer, and other copolymerizable vinyl monomers 50 used as necessary Rubber particle core made of rubber elastic body, polysiloxane rubber-based elastic body, or a mixture thereof composed of mass% or less (Ba-2): (meth) acrylic acid ester, aromatic vinyl compound, and vinyl cyanide compound Shell layer comprising a polymer obtained by (co) polymerizing one or more selected from the group consisting of

[5] The rubber-like polymer particles of the component (B) are (Bb-2) (meth) acrylic acid ester 70 to 100 mass in the presence of (Bb-1) acrylic rubber and / or conjugated diene rubber. %, Rubber-like polymer particles (Bb) obtained by (co) polymerizing monomer components consisting of 0-30 mass% aromatic vinyl monomer and 0-30 mass% of other copolymerizable monomers The epoxy resin composition for optical element sealing materials according to any one of [1] to [3].

[6] The curing agent of component (C) is one or more selected from the group consisting of hexahydrophthalic anhydride and glycol-modified products thereof, methylhexahydrophthalic anhydride and glycol-modified products thereof, and onium salts. The epoxy resin composition for optical element sealing materials according to any one of [1] to [5], wherein

[7] Further, the following (D) component and / or (E) component is contained in an amount of 0.01 to 10% by mass with respect to the total epoxy resin component, respectively [1] to [6] An epoxy resin composition for an optical element sealing material according to claim 1.
(D) component; 1 type, or 2 or more types of antioxidant chosen from the group which consists of a phenolic antioxidant, sulfur type antioxidant, and phosphorus antioxidant (E) component; UV absorber

[8] The rubber-like polymer particles of the component (B) are dispersed in the whole or a part of the epoxy resin component, and then mixed with other components. [1] to [7] ] The epoxy resin composition for optical element sealing materials in any one of.

[9] The epoxy resin composition for optical element sealing materials according to any one of [1] to [8], wherein the optical element is a light emitting element having a main emission peak at a wavelength of 350 to 550 nm.

[10] The epoxy resin composition for optical element sealing materials according to any one of [1] to [9], wherein the optical element is a light emitting diode (LED).

[11] An epoxy resin cured product obtained by curing the epoxy resin composition for optical element sealing materials according to any one of [1] to [10].

  The cured product of the epoxy resin composition for optical element sealing material of the present invention is excellent in heat resistance, moisture resistance (moisture absorption resistance) and adhesion, and has sufficient strength, and also has excellent light resistance. It can be industrially advantageously used as an epoxy resin composition for a sealing material of an optical element such as an LED using a group III nitride compound semiconductor that emits light of a short wavelength.

Hereinafter, embodiments of the present invention will be described in detail.
In this specification, “(meth)) acryl” is a general term for “acryl” and “methacryl”, and the same applies to “(meth) acrylate”.
“(Co) polymerization” means “polymerization” or “copolymerization”.

[Epoxy resin composition for sealing material]
The epoxy resin composition for optical element sealing materials of this invention contains the following (A) component, (B) component, and (C) component, and content of (A) component is 100 with respect to all the epoxy resin components. The content of the component (B) is 1 to 50% by mass with respect to all the epoxy resin components, and the light transmittance at a wavelength of 400 nm of a cured product having a thickness of 2 mm ± 0.2 mm is 70. % Or more. The epoxy resin composition for an optical element sealing material of the present invention further contains the following component (D) and / or component (E) in an amount of 0.01 to 10% by mass with respect to the total epoxy resin component. Is preferred.
(A) component; alicyclic epoxy resin (B) component; rubber-like polymer particles
Component (C): One or more curing agents selected from the group consisting of acid anhydrides, acid anhydride modifications, and cationic polymerization initiators (D) Component: phenolic antioxidants, sulfur oxidations 1 type, or 2 or more types of antioxidant chosen from the group which consists of an antioxidant and phosphorus antioxidant (E) component; Ultraviolet absorber Each component is demonstrated below.

{(A) component: alicyclic epoxy resin}
As the alicyclic epoxy resin of component (A) of the epoxy resin composition for optical element sealing material of the present invention, an epoxy resin obtained by epoxidizing a cyclic olefin, an epoxidized product of hydrogenated bisphenol A, and an aromatic epoxy resin An epoxy resin obtained by hydrogenating an epoxy resin, an epoxy resin obtained from a carboxylic acid such as methylhexahydrophthalic acid, etc., and an epoxy resin obtained by epoxidizing a cyclic olefin for reasons such as low chlorine content, and Those selected from epoxy resins obtained by hydrogenating aromatic epoxy resins are preferred.

  Examples of alicyclic epoxy resins obtained by epoxidizing cyclic olefins include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 1,2-epoxy-vinylcyclohexene, bis (3, 4-epoxycyclohexylmethyl) adipate, 1-epoxyethyl-3,4-epoxycyclohexane, limonene diepoxide, oligomeric alicyclic epoxy resin (Daicel Chemical Industries, Ltd. trade name; Epolide GT300, Epolide GT400, EHPE-3150), etc. An epoxy resin obtained by epoxidizing any of these olefins. Among these, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate is preferable, and when this alicyclic epoxy resin is blended, the viscosity of the epoxy resin composition can be reduced, Can be improved.

  Examples of epoxy resins obtained by hydrogenating aromatic epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol. Type epoxy resin, biphenol type epoxy resin such as 4,4′-biphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, naphthalenediol type epoxy resin, trisphenylol methane Epoxy resin obtained by hydrogenating an aromatic ring of an aromatic epoxy resin such as an epoxy resin, a tetrakisphenylolethane type epoxy resin, and a phenol dicyclopentadiene novolac type epoxy resin. Of these, hydrogenated epoxy resins obtained by hydrogenating the aromatic rings of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and biphenol type epoxy resin are particularly preferable because an epoxy resin having a high hydrogenation rate can be obtained.

  The hydrogenation rate of the hydrogenated epoxy resin obtained by hydrogenating such an aromatic epoxy resin is preferably 90 to 100%, and more preferably 95 to 100%. When the hydrogenation rate is less than 90%, when a nitride semiconductor LED is encapsulated, it absorbs short-wavelength light, the resin deteriorates over time, and the light emission luminance decreases significantly due to yellowing. It is not preferable. This hydrogenation rate can be measured by determining a change in absorbance (wavelength; 275 nm) using a spectrophotometer.

The hydrogenated epoxy resin as described above can be produced by selectively hydrogenating an aromatic ring by a known method in the presence of a catalyst. An example of a more preferable production method is a method in which an aromatic ring is selectively hydrogenated in the presence of a catalyst in which an aromatic epoxy resin is dissolved in an organic solvent and rhodium or ruthenium is supported on graphite. As the graphite of the catalyst carrier, it is preferable to use a graphite having a surface area in the range of 10 to 400 m ² / g. The reaction is usually carried out within a range of a pressure of 1 to 30 MPa, a temperature of 30 to 150 ° C., and a time of 0.5 to 20 hours. After completion of the reaction, the catalyst and the like are removed by filtration, and the organic solvent is distilled off under reduced pressure until it substantially disappears to obtain a hydrogenated epoxy resin.

  The above alicyclic epoxy resins may be used alone or in combination of two or more.

In addition, as for the total chlorine content of the alicyclic epoxy resin of (A) component, 0.3 mass% or less is preferable. If the total chlorine content exceeds 0.3% by mass, the moisture resistance, the high temperature electrical characteristics and the light resistance are deteriorated, and the metal material of the object to be sealed is corroded.
In this specification, “total chlorine” refers to all chlorine contained in the epoxy resin.

  In addition, the epoxy equivalent (WPE) of the alicyclic epoxy resin as the component (A) is preferably 100 to 4000 g / equivalent. When the epoxy equivalent exceeds 4000 g / equivalent, the viscosity of the epoxy resin composition becomes high and handling becomes difficult, which is not preferable. If the epoxy equivalent is less than 100 g / equivalent, the molecular weight of the epoxy resin becomes too small, and the epoxy resin evaporates during epoxy curing, which is not preferable.

  (A) component in the epoxy resin composition for optical element sealing materials of this invention; the mixture ratio of an alicyclic epoxy resin is 100-50 mass% with respect to all the epoxy resin components, Preferably it is 100-70 mass. %, More preferably 100 to 80% by mass. If the blending ratio of the alicyclic epoxy resin is too small, the light deterioration resistance is remarkably lowered, which is not preferable.

In order to balance physical properties such as heat resistance and adhesion, as a component (A) of the epoxy resin composition for an optical element sealing material of the present invention, an epoxy resin obtained by hydrogenating an aromatic epoxy resin and a cyclic olefin are epoxidized. The blending ratio when using the resulting alicyclic epoxy resin in combination is
(A) 100% by mass of component Epoxy resin obtained by hydrogenating aromatic epoxy resin: 5 to 95% by mass
Alicyclic epoxy resin obtained by epoxidizing cyclic olefin: 95-5% by mass
Is preferable.
When there are too many epoxy resins which hydrogenated the aromatic epoxy resin, it will be inferior to heat resistance, and when there are too many alicyclic epoxy resins obtained by epoxidizing a cyclic olefin, it will be inferior to adhesiveness or flexibility.

{Other epoxy resins}
The epoxy resin composition for optical element sealing material of the present invention can be used in combination with other epoxy resins of the component (A) within the range not impairing the effects of the present invention. Examples of other epoxy resins that can be used in combination include the following.

(1) Bifunctional epoxy resin having an aromatic ring structure Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, diglycidyl ether of bisphenol A-alkylene oxide adduct, alkylene oxide adduct of bisphenol F Diglycidyl ether, bisphenol S type epoxy resin, tetramethyl bisphenol A type epoxy resin, tetramethyl bisphenol F type epoxy resin, thiodiphenol type epoxy resin, dihydroxy diphenyl ether type epoxy resin, terpene diphenol type epoxy resin, biphenol type epoxy Resin, tetramethylbiphenol type epoxy resin, hydroquinone type epoxy resin, methyl hydroquinone type epoxy resin, dibutyl hydroxyl Emission type epoxy resins, resorcin type epoxy resin, methyl resorcin type epoxy resin, dihydroxynaphthalene type epoxy resin

(2) Polyfunctional type epoxy resin Phenol novolak type epoxy resin; Cresol novolak type epoxy resin; Bisphenol A novolak type epoxy resin; Dicyclopentadiene phenol type epoxy resin; Terpene phenol type epoxy resin; Phenol aralkyl type epoxy resin; Epoxy resin; naphthol novolak type epoxy resin; polyhydric phenol resin obtained by condensation reaction with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal, heavy petroleum oil or pitches, formaldehyde polymer and phenols Epoxy resin produced from various phenolic compounds such as modified phenolic resin obtained by polycondensation in the presence of an acid catalyst and epihalohydrin

(3) Epoxy resins having other structures Manufactured from various amine compounds such as diaminodiphenylmethane, aminophenol and xylenediamine, and epoxy resins produced from epihalohydrin, various carboxylic acids such as dimer acid, and epihalohydrin Reactive diluent for epoxy resin such as epoxy resin, epoxy resin produced from aliphatic monoalcohol or polyhydric alcohol and epihalohydrin, glycidyl ester of aliphatic carboxylic acid, glycidyl ether of monophenol

  The above-mentioned other epoxy resins may be used alone or in combination of two or more.

{(B) component; rubber-like polymer particles}
Component (B) used in the epoxy resin composition for a light emitting device sealing material of the present invention; the composition, structure and the like of the rubber-like polymer particles are not particularly limited as long as the effects of the present invention are obtained. Polymer particles (Ba) or rubber-like polymer particles (Bb) are preferred.
In addition, you may use together rubber-like polymer particle (Ba) and rubber-like polymer particle (Bb) as rubber-like polymer particle of (B) component.

Rubbery polymer particles (Ba): rubber obtained by graft polymerization of 5 to 50% by mass of the shell layer of (Ba-2) below with respect to 50 to 95% by mass of the rubber particle core of the following (Ba-1) Polymeric particles (Ba-1): 50% by mass or more of one or more monomers selected from the group consisting of a diene monomer and a (meth) acrylic acid ester monomer, and other copolymerization used as necessary Rubber particle core comprising a rubber elastic body composed of 50% by mass or less of a vinyl monomer, a polysiloxane rubber-based elastic body, or a mixture thereof (Ba-2): (meth) acrylic acid ester, aromatic vinyl compound, and Shell layer comprising a polymer obtained by (co) polymerizing one or more selected from the group consisting of vinyl cyanide compounds

  Rubber-like polymer particles (Bb): (Bb-2) (Meth) acrylic acid ester 70 to 100% by mass, aromatic vinyl monomer in the presence of (Bb-1) acrylic rubber and / or conjugated diene rubber Rubber-like polymer particles obtained by (co) polymerizing monomer components consisting of 0-30% by mass and other copolymerizable monomers 0-30% by mass

<Regarding Rubbery Polymer Particles (Ba)>
First, rubbery polymer particles (Ba) will be described.

In the above-mentioned rubber-like polymer particles (Ba), the core portion (Ba-1) is made of a polymer mainly composed of an elastomer or a rubber-like polymer, and the shell layer (Ba-2) has the core portion ( What consists of the polymer component graft-polymerized to Ba-1) is preferable.
Here, the shell layer (Ba-2) is formed so as to cover part or all of the surface of the core part by graft polymerization of the monomer constituting the graft component of the shell layer to the component constituting the core particle. can do.

(About the core (Ba-1))
The polymer constituting the core part (Ba-1) is cross-linked, and can swell in a good solvent of the polymer constituting the core part, but is not substantially dissolved and preferably insoluble in the epoxy resin. . The gel content of the core (Ba-1) is preferably 60% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 95% by mass or more. Since the polymer constituting the core part (Ba-1) preferably has properties as rubber, the glass transition temperature (Tg) is preferably 0 ° C. or lower, preferably −10 ° C. or lower.

  The polymer constituting the core part (Ba-1) is composed of a monomer containing 50% by mass or more of at least one monomer selected from conjugated diene monomers and (meth) acrylic acid ester monomers, or It is preferable to use polysiloxane rubber or these in combination.

  Examples of the conjugated diene monomer constituting the core part (Ba-1) include butadiene, isoprene, chloroprene, etc., but they are available at a low price, and the properties of the resulting polymer as rubber are good. In view of easy polymerization, butadiene is particularly preferable.

Examples of the (meth) acrylic acid ester monomer constituting the core part (Ba-1) include butyl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate, etc., but the properties of the resulting polymer as rubber are good. From the viewpoint of easy polymerization, butyl acrylate and 2-ethylhexyl acrylate are particularly preferable.
These can be used alone or in combination of two or more.

  The amount of the conjugated diene monomer and / or the (meth) acrylic acid ester monomer used is preferably 50% by mass or more, more preferably 60% by mass or more based on the total weight of the core part (Ba-1). When this ratio is less than 50% by mass, the ability to impart toughness to the epoxy resin may decrease.

  The polymer constituting the core part (Ba-1) is one or more kinds of vinyl copolymerizable with the conjugated diene monomer or (meth) acrylic acid ester monomer as the main component. There may be a copolymerized polymer with a monomer. Examples of such monomers include alkyl (meth) acrylates other than the above-described alkyl (meth) acrylate, vinyl aromatic monomers such as styrene and α-methylstyrene, and vinylcyan monomers such as (meth) acrylonitrile and substituted acrylonitrile. It can be illustrated. These can be used alone or in combination of two or more. The amount of other copolymerizable vinyl monomers used is preferably 50% by mass or less, more preferably 40% by mass or less, based on the total weight of the core part (Ba-1).

  Moreover, you may use a polyfunctional monomer as a component which comprises the said core part (Ba-1), in order to adjust a crosslinking degree. Examples of the polyfunctional monomer include divinylbenzene, butanediol di (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, allyl (meth) acrylate, diallyl itaconate, diallyl phthalate, and the like. These can be used alone or in combination of two or more. The usage-amount of these polyfunctional monomers is 10 mass% or less with respect to the total weight of a core part (Ba-1), Preferably it is 5 mass% or less, More preferably, it is 3 mass% or less. If the polyfunctional monomer is used in excess of 10% by mass, the properties of the core part (Ba-1) as an elastomer are impaired, which is not preferable.

  Furthermore, it is also possible to use a polysiloxane rubber as the core part (Ba-1) instead of the vinyl polymerizable polymer as described above or in combination with these. When polysiloxane rubber is used as the core (Ba-1), for example, polysiloxane rubber 1 composed of alkyl or allyl disubstituted silyloxy units such as dimethylsilyloxy, methylphenylsilyloxy, diphenylsilyloxy, etc. Species or two or more can be used. When using such a polysiloxane rubber, if necessary, partially use a polyfunctional alkoxysilane compound during polymerization, or radically react a silane compound having a vinyl reactive group. It is more preferable to introduce a crosslinked structure in advance, for example.

(About shell layer (Ba-2))
The shell layer (Ba-2) has a function of giving affinity to the epoxy resin so that the rubber-like polymer particles (Ba) are stably dispersed in the state of primary particles in the epoxy resin. The polymer constituting the shell layer (Ba-2) is graft-polymerized to the polymer constituting the core part (Ba-1), and is substantially bonded to the polymer constituting the core part (Ba-1). It is preferable. Specifically, the polymer constituting the shell layer (Ba-2) is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more bonded to the core part (Ba-1). It is desirable that The shell layer (Ba-2) preferably has swelling, compatibility or affinity for the organic solvent and alicyclic epoxy resin (A) described later. Further, the shell layer (Ba-2) has reactivity with the alicyclic epoxy resin (A) or the curing agent (C) compounded at the time of use depending on the necessity at the time of use, and the alicyclic type. Under the condition that the epoxy resin (A) is cured by reacting with the curing agent (C), the epoxy resin (A) may have a function of chemically reacting with these to form a bond.

  The polymer constituting the shell layer (Ba-2) can be obtained at a low cost, and can have both good graft polymerizability and affinity for the epoxy resin. A polymer or copolymer obtained by polymerizing or copolymerizing at least one component selected from a group vinyl compound and a vinyl cyanide compound is preferred. Further, in particular, when chemical reactivity at the time of curing the epoxy resin of the shell layer is obtained, in addition to the above-mentioned monomers, it has reactive side chains such as hydroxyalkyl (meth) acrylate and epoxyalkyl (meth) acrylate ( Monomer group consisting of (meth) acrylic acid esters, epoxy alkyl vinyl ether, (meth) acrylamide (including N-substituted), α, β-unsaturated acid, α, β-unsaturated acid anhydride, and maleic acid derivative A copolymer obtained by copolymerizing one or more components selected from the above is more preferred. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene, α-methylstyrene, (meth) acrylonitrile, (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, Examples thereof include glycidyl (meth) acrylate, glycidyl vinyl ether, (meth) acrylamide, maleic anhydride, maleic imide and the like. It is not limited to these. These 1 type can be used individually or in combination of 2 or more types as appropriate.

(Core / shell ratio)
A preferable core part (Ba-1) / shell layer (Ba-2) ratio (mass ratio) in the rubber-like polymer particles (Ba) used in the epoxy resin composition for a light emitting device sealing material of the present invention is 50 / It is preferable that it is the range of 50-95 / 5, More preferably, it is 60 / 40-90 / 10. When the ratio of core part ((Ba-1) / shell layer (Ba-2) (weight ratio) exceeds 50/50 and the ratio of core part (Ba-1) decreases, the ratio to the alicyclic epoxy resin (A) On the other hand, when the ratio of the shell layer (Ba-2) is decreased to exceed 95/5, aggregation tends to occur during handling in the present invention, and problems arise in operability. Expected physical properties may not be obtained.

  There is no restriction | limiting in particular about the manufacturing method of such rubber-like polymer particle (Ba), It can manufacture by a well-known method, for example, emulsion polymerization, suspension polymerization, micro suspension polymerization, etc. Among these, the production method by emulsion polymerization is particularly suitable.

  The particle diameter of the rubber-like polymer particles (Ba) used in the epoxy resin composition for a light-emitting device sealing material of the present invention is not particularly limited as long as the effect of the present invention is obtained, and the rubber-like particles are in an aqueous latex state. Anything that can be stably obtained can be used without problems. From the viewpoint of industrial productivity, those having a volume average particle size of about 0.03 to 1 μm are preferable in terms of easy production. The volume average particle diameter of the rubber-like polymer particles can be measured using Microtrac UPA (manufactured by Nikkiso Co., Ltd.).

<Rubber polymer particles (Bb)>
Next, the rubber-like polymer particles (Bb) will be described.

  The rubber-like polymer particles (Bb) are (Bb-2) (meth) acrylic acid ester in an amount of 70 to 100% by mass, preferably 80 in the presence of (Bb-1) acrylic rubber and / or conjugated diene rubber. ~ 100% by weight, aromatic vinyl monomer 0-30% by weight, preferably 0-20% by weight and other copolymerizable monomers 0-30% by weight, preferably 0-15% by weight (total 100% by weight) It is formed by polymerizing a monomer component.

  (Bb-2) As a usage rate of a monomer component, it is preferable that it is 20-65 mass parts with respect to 100 mass parts of (Bb-1) rubber components, especially 28-45 mass parts. If this proportion exceeds 65 parts by mass, the effect of improving the strength tends to decrease, and if it is less than 20 parts by mass, it becomes difficult to produce a stable material in practice, and the effect of improving brittleness also tends to decrease. Occurs.

  In addition, in the (Bb-2) monomer component constituting the rubber-like polymer particle (Bb), when the (meth) acrylic acid ester is less than 70% by mass, the compatibility is lowered and the effect of improving brittleness is lowered. A trend arises. Moreover, when an aromatic vinyl monomer exceeds 30 mass%, there exists a tendency for a weather resistance to fall.

  The method for polymerizing the rubber-like polymer particles (Bb) is not particularly limited, but a known emulsion polymerization method is advantageous for practical use.

  In addition, as an average particle diameter in the latex of the rubber component (Bb-1) of the rubber-like polymer particles (Bb), a value measured by a light scattering method using a light source having a wavelength of 546 nm is 100 to 400 nm. Furthermore, the thing of 150-300 nm is preferable. In view of weather resistance, acrylic rubber is more preferable than conjugated diene rubber.

  As said acrylic rubber, what was manufactured by the manufacture example 3 mentioned later, for example is mentioned. These may be used alone or in combination of two or more.

  Examples of the conjugated diene rubber include those having a refractive index adjusted by copolymerization of a diene monomer and styrene. These may be used alone or in combination of two or more.

  (Bb-2) As said (meth) acrylic acid ester which comprises a monomer component, for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid n -Octyl and the like. These may be used alone or in combination of two or more.

  (Bb-2) Examples of the aromatic vinyl monomer constituting the monomer component include styrene and α-methylstyrene. These may be used alone or in combination of two or more.

  Examples of the other copolymerizable monomer include acrylonitrile. These may be used alone or in combination of two or more.

  As the rubber-like polymer particles (Bb), those of various multilayer structures are known. For example, the multilayer structure disclosed in Japanese Patent Publication No. 55-27576, manufactured in Production Example 3 described later, is used. Things.

<(B) component; blending ratio of rubber-like polymer particles>
Component (B) such as the aforementioned rubber-like polymer particles (Ba) and / or rubber-like polymer particles (Bb) in the epoxy resin composition for optical element sealing material of the present invention; blending of rubber-like polymer particles A ratio is 1-50 mass% with respect to all the epoxy resin components, Preferably it is 1-40 mass%, More preferably, it is 1-30 mass%. When the blending ratio of the rubber-like polymer particles is too small, the effect of the present invention due to the use of the component (B) cannot be sufficiently obtained, and when it is too large, the transparency of the cured product is lowered, which is not preferable.

{(C) component; curing agent}
Component (C) used in the epoxy resin composition for optical element sealing material of the present invention; the curing agent is selected from the group consisting of an acid anhydride, a modified acid anhydride, and a cationic polymerization initiator.

<Acid anhydride>
The acid anhydride as a curing agent in the epoxy resin composition for a light emitting device sealing material of the present invention is preferably an acid anhydride having no carbon-carbon double bond in the molecule. Examples thereof include hydrophthalic acid, methylhexahydrophthalic anhydride, hydrogenated nadic anhydride, hydrogenated methyl nadic anhydride, hydrogenated trialkylhexahydrophthalic anhydride, and 2,4-diethylglutaric anhydride. These may be used alone or in combination of two or more. Among these, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride are particularly preferable in that they have excellent heat resistance and a colorless cured product can be obtained.

  When only the acid anhydride is used as the curing agent, the blending ratio of the acid anhydride varies depending on the epoxy equivalent of the total epoxy resin component of the epoxy resin composition for optical element sealing material, but preferably 100 parts by mass of the total epoxy resin component On the other hand, it mix | blends within the range of 40-200 mass parts.

<Modified product of acid anhydride>
The modified acid anhydride in the epoxy resin composition for a light emitting device sealing material of the present invention is the above-mentioned acid anhydride, preferably hexahydrophthalic anhydride or methylhexahydrophthalic acid modified with glycol or the like. Is.
Examples of glycols that can be used for modification include glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol; and two or more of these Copolymer polyether glycols of glycol and / or polyether glycol can be used. These may be used alone or in combination of two or more.

  The amount of modification is preferably 0.4 mol or less of glycol with respect to 1 mol of acid anhydride. When the amount of modification increases, the viscosity of the composition increases, workability deteriorates, the reactivity with the epoxy resin decreases, the curing slows down, and the productivity when sealing the device is deteriorated. This is not preferable.

  When only the modified acid anhydride is used as the curing agent, the blending ratio of the modified acid anhydride varies depending on the epoxy equivalent of all the epoxy resin components of the epoxy resin composition for optical element sealing material, but preferably all It mix | blends within the range of 40-200 mass parts with respect to 100 mass parts of epoxy resin components.

<Cationic polymerization initiator>
The cationic polymerization initiator as a curing agent in the epoxy resin composition for optical element sealing material of the present invention includes an active energy ray cationic polymerization initiator that generates a cationic species or a Lewis acid by active energy rays, or a cation by heat. Thermal cationic polymerization initiators that generate seeds or Lewis acids can be used.

Examples of active energy ray cationic polymerization initiators include metal fluoroboron complex salts and boron trifluoride complex compounds as described in US Pat. No. 3,379,653; bis (perfluoroalkyls) as described in US Pat. No. 3,586,616. Sulfonyl) methane metal salts; aryldiazonium compounds as described in US Pat. No. 3,708,296; aromatic onium salts of Group VIa elements of the periodic table as described in US Pat. No. 4,058,400; Aromatic onium salts of Group Va elements of the periodic table as described; dicarbonyl chelates of Group IIIa to Va elements of the periodic table as described in US Pat. No. 4068091; described in US Pat. No. 4,139,655 Such thiopyrylium salts; MF ₆ as described in US Pat. No. 4,161,478 ^- anion (where M is phosphorus, are selected from antimony and arsenic) form of the periodic table VIb element; described in U.S. Pat. No. 4,256,828; U.S. Pat arylsulfonium complex salts as described in No. 4,231,951 Aromatic iodonium complex salts and aromatic sulfonium complex salts; R. Bis [4- (diphenyl) as described by Watt et al. In "Journal of Polymer Science, Polymer Chemistry Edition", Vol. 22, p. 1789 (1984). Sulfonio) phenyl] sulfide-bis-hexafluorometal salts (for example, phosphates, arsenates, antimonates, etc.). In addition, mixed ligand metal salts of iron compounds and silanol-aluminum complexes can also be used.

  Preferred cationic active energy ray cationic polymerization initiators include arylsulfonium complex salts, aromatic sulfonium or iodonium salts of halogen-containing complex ions, and aromatic onium salts of Group II, V and VI elements of the periodic table. The Some of these salts are FX-512 (3M), UVR-6990 and UVR-6974 (Union Carbide), UVE-1014 and UVE-1016 (General Electric) ), KI-85 (Degussa), SP-150 and SP-170 (Asahi Denka) and Sun Aid SI-60L, SI-80L and SI-100L (Sanshin Chemical Co., Ltd.). .

  As the thermal cationic polymerization initiator, a cationic or protonic acid catalyst such as a triflic acid salt, a boron trifluoride ether complex compound, boron trifluoride or the like can be used. A preferred thermal cationic polymerization initiator is a triflate, for example, diethylammonium triflate, triethylammonium triflate, diisopropylammonium triflate, ethyl diisopropylammonium triflate etc. available from 3M as FC-520 ( Many of these are described by Modern Coatings published in October 1980 by RR Alm). On the other hand, among aromatic onium salts used as active energy ray cationic polymerization initiators, there are those that generate cationic species by heat, and these can also be used as thermal cationic polymerization initiators. Examples include Sun Aid SI-60L, SI-80L, and SI-100L (Sanshin Chemical Industry Co., Ltd.).

  Among these photo and thermal cationic polymerization initiators, onium salts are preferable because they are easy to handle and have a good balance between latency and curability. Among them, diazonium salts, iodonium salts, sulfonium salts, and phosphonium salts are preferable. It is particularly preferable in terms of excellent balance between handleability and latency.

  These cationic polymerization initiators may be used alone or in combination of two or more.

When only the cationic polymerization initiator is used as the curing agent, the blending ratio of the cationic polymerization initiator varies depending on the epoxy equivalent of all epoxy resin components of the epoxy resin composition for optical element sealing material, but 100 parts by mass of all epoxy resin components The amount is preferably 0.01 to 15 parts by mass, more preferably 0.05 to 5 parts by mass.
If it is out of the above range, the balance of heat resistance and moisture resistance of the cured epoxy resin is deteriorated, which is not preferable.

{Curing accelerator}
When using an acid anhydride and / or a modified product of an acid anhydride as a curing agent, the epoxy resin composition for a light emitting device sealing material of the present invention includes an epoxy resin and an acid anhydride and / or a modified product thereof. For the purpose of accelerating the curing reaction, a curing accelerator can be used.

  Examples of curing accelerators include tertiary amines and salts thereof, imidazoles and salts thereof, organic phosphine compounds, zinc octylates, tin octylates and other organic acid metal salts, and particularly preferred curing accelerators are Organic phosphine compounds.

  The blending ratio of the curing accelerator is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the acid anhydride and / or modified product blended as the curing agent. If it is out of the above range, the balance of heat resistance and moisture resistance of the cured epoxy resin is deteriorated, which is not preferable.

{(D) component; antioxidant}
The epoxy resin composition for optical element sealing material of the present invention is preferably blended with component (D); an antioxidant to prevent oxidative deterioration during heating and to produce a cured product with little coloring.
As the antioxidant, phenol-based, sulfur-based, and phosphorus-based antioxidants can be used. Specific examples include the following antioxidants.

(Phenolic antioxidant)
Monophenols; 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate, etc. Bisphenols; 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-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane, etc. Polymer Phenols; 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-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 the like.

(Sulfur-based antioxidant)
Dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, etc.

(Phosphorus antioxidant)
Phosphites; triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris (2,4-di-t-butylphenyl) phosphite, Cyclic neopentanetetraylbis (octadecyl) phosphite, cyclic neopentanetetraylbi (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbi (2,4-di-t-butyl) -4-methylphenyl) phosphite, bis [2-t-butyl-6-methyl-4- {2- (octadecyloxycarbonyl) ethyl} phenyl] hydrogen phosphite, etc. Oxaphosphaphenanthrene oxides; 9,10 - Dro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene -10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc.

  These antioxidants may be used alone or in combination of two or more, but may be used in a phenolic / sulfur combination or a phenolic / phosphorus combination. Particularly preferred.

  The blending ratio of these antioxidants is preferably 0.01 to 10% by mass with respect to the total epoxy resin components of the epoxy resin composition for optical element sealing materials of the present invention. When the blending amount of the antioxidant is too small, it is not possible to obtain a sufficient addition effect, and when it is too large, the physical properties after curing, in particular, the UV deterioration resistance is lowered, which is not preferable.

{(E) component; UV absorber}
The epoxy resin composition for optical element sealing material of the present invention can also contain (E) component; an ultraviolet absorber to further improve the light resistance.
As the UV absorber, a general UV absorber for plastics can be used, and examples thereof include the following.

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- Benzophenones such as 4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone 2 -(2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di tert-butylphenyl) ben Triazole, 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'-hydroxy-3', 3 '', 4 '', Benzotriazoles such as 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 (1,2,2,6,6-pentamethyl-4-piperidyl) [{3,5-bis (1,1-dimethylethyl) -4 -Hydroxyphenyl} methyl] butyl malonate and other hindered amines

  The blending ratio of these ultraviolet absorbers is preferably 0.01 to 10% by mass with respect to the total epoxy resin component of the epoxy resin composition for optical element sealing material of the present invention. If the blending amount of the antioxidant is too small, a sufficient addition effect cannot be obtained, and if it is too much, the physical properties after curing, particularly the heat deterioration resistance is lowered, which is not preferable.

{Other additives}
In the epoxy resin composition for optical element sealing material of the present invention, in addition to the above components, other additives are added as necessary so as not to impair the properties of the epoxy resin composition for optical element sealing material of the present invention. It can mix | blend suitably.
Examples of other additives include the following.

(i) Powdery reinforcing agents and fillers, for example, metal oxides such as aluminum oxide and magnesium oxide, silicon compounds such as finely divided silica, fused silica and crystalline silica, transparent fillers such as glass beads, and metals such as aluminum hydroxide Hydroxides, others, kaolin, mica, quartz powder, graphite, molybdenum disulfide, etc. These reinforcing agents and fillers are blended within a range that does not impair the transparency of the epoxy resin composition for optical element sealing materials of the present invention. In general, 100 parts by mass or less is appropriate for 100 parts by mass of all epoxy resin components of the epoxy resin composition of the present invention.

(ii) Coloring agents or pigments such as titanium dioxide, molybdenum red, bitumen, ultramarine blue, cadmium yellow, cadmium red and organic dyes
(iii) Flame retardants For example, antimony trioxide, bromine compounds and phosphorus compounds
(iv) Ion adsorbent
(v) Coupling agent The components (ii) to (v) are usually blended in an amount of 0.01 to 30 parts by mass per 100 parts by mass of the total epoxy resin component of the epoxy resin composition of the present invention. .

The epoxy resin composition for optical element sealing material of the present invention may further contain various curable monomers, oligomers and synthetic resins for the purpose of improving the properties of the epoxy cured product.
Examples of such compounds and resins for improving properties include diluents for epoxy resins such as aliphatic epoxies, diols or triols, vinyl ethers, oxetane compounds, fluororesins, acrylic resins, silicone resins, etc. One type or a combination of two or more types can be mentioned.
The compounding ratio of these compounds and resins is 50 in an amount within a range not impairing the original properties of the epoxy resin composition of the present invention, that is, 100 parts by mass of all epoxy resin components of the epoxy resin composition of the present invention. The mass part or less is preferable.

[Method for producing epoxy resin composition for optical element sealing material of the present invention]
Although the epoxy resin composition for optical element sealing materials of this invention is prepared by mixing the predetermined amount of the structural component of the above-mentioned epoxy resin composition for optical element sealing materials of this invention, Component B) In order to sufficiently obtain the effects of the present invention by blending rubbery polymer particles, it is necessary to sufficiently disperse the rubbery polymer particles of component (B) in the resin component. For this purpose, the rubber-like polymer particles of the component (B) are dispersed in advance in the whole amount or a part of the epoxy resin component by the method as described below, and then the remaining components are mixed to mix the optical component of the present invention. It is preferable to obtain an epoxy resin composition for an element sealing material.

Here, the epoxy resin component in which the rubber-like polymer particles of the component (B) are preliminarily dispersed is another epoxy resin that is included as necessary even if it is the alicyclic epoxy resin of the component (A). Although it may be, it is preferable that it is an alicyclic epoxy resin of (A) component.
When the rubber-like polymer particles of the component (B) are dispersed in advance in the epoxy resin component, the content of the rubber-like polymer particles of the component (B) is the sum of the rubber-like polymer particles and the epoxy resin. On the other hand, it is preferable to disperse other components to 5 to 50% by mass, preferably 10 to 50% by mass. At the time of this preliminary dispersion, if the amount of the epoxy resin is less than this range, it is not possible to obtain a sufficient uniform dispersibility improvement effect by dispersing the component (B) in advance. It becomes difficult to adjust the blending amount of component (B) in the entire epoxy resin composition.

  The (A) component alicyclic epoxy resin in which the (B) component rubber-like polymer particles are dispersed in advance and the (A) component alicyclic epoxy resin mixed together with other components are the same type. It may be different or different.

The mixing of the rubber-like polymer particles (B) and the epoxy resin (A) is preferably performed by the specific method described below.
That is, the rubber-like polymer particles (B) obtained in the state of an aqueous latex by the method for producing rubber-like polymer particles explained in the above-mentioned section of {(B) component; rubber-like polymer particles} in an organic solvent. And after obtaining a dispersion in which the rubber-like polymer particles (B) are dispersed in an organic solvent, the dispersion is mixed with at least a part of the alicyclic epoxy resin (A). As such a method, it is preferable to use, for example, a method described in JP-A No. 2004-315572, re-published WO 2004/108825, or JP-A 2005-255822.

  More specifically, the aqueous latex containing the rubber-like polymer particles (B) is mixed with a specific organic solvent, and the aqueous phase is separated and removed so that the rubber-like polymer particles (B) are in the organic solvent. A dispersion dispersed in (1) is obtained, and the alicyclic epoxy resin (A) is mixed with the dispersion, and then the organic solvent is removed as necessary. When obtaining a dispersion in which the rubber-like polymer particles (B) are dispersed in an organic solvent, it is preferable to mix an aqueous latex of the rubber-like polymer particles (B) with a specific organic solvent, and then add a water-soluble electrolyte or aqueous solution. After adding the latex and the immiscible organic solvent, the aqueous phase is separated and removed to obtain a dispersion in which the rubber-like polymer particles (B) are dispersed in the organic solvent. By mixing this with the alicyclic epoxy resin (A) and removing volatile components including the organic solvent as necessary, the rubbery polymer particles are sufficiently added to the alicyclic epoxy resin (A). It can be uniformly dispersed. As a more preferable method, after the above-described dispersion in which the rubber-like polymer particles (B) are dispersed in an organic solvent is brought into contact with water or a water-soluble electrolyte aqueous solution, the operation of separating and removing the aqueous phase is performed one or more times. The method of mixing with an alicyclic epoxy resin (A) later is mentioned.

  Here, as the specific organic solvent to be mixed with the aqueous latex containing the rubber-like polymer particles (B), for example, esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, acetone, methyl ethyl ketone, diethyl ketone, Ketones such as methyl isobutyl ketone, alcohols such as ethanol, propanol, isopropanol and butanol, ethers such as tetrahydrofuran, tetrahydropyran, dioxane and diethyl ether, aromatic hydrocarbons such as benzene, toluene and xylene, methylene chloride, One or more organic solvents selected from halogenated hydrocarbons such as chloroform or a mixture thereof may be mentioned. When the solubility of the organic solvent in water at 20 ° C. is less than 5% by mass, a rubber-like polymer is used. Water containing particles (B) Mixing with latex tends to be somewhat difficult. Conversely, if it exceeds 40% by mass, the aqueous phase is then efficiently added after adding a water-soluble electrolyte or an immiscible organic solvent with aqueous latex. Since it tends to be difficult to separate and remove, the solubility of the organic solvent used in water at 20 ° C. is preferably 5 to 40% by mass.

  Moreover, a well-known organic solvent can be used as an organic solvent immiscible with aqueous latex. For example, esters such as ethyl acetate, propyl acetate and butyl acetate, ketones such as diethyl ketone and methyl isobutyl ketone, ethers such as diethyl ether and butyl ether, aromatic hydrocarbons such as benzene, toluene and xylene, methylene chloride Examples thereof include one or more organic solvents selected from halogenated hydrocarbons such as chloroform, or a mixture thereof, preferably having a water solubility of less than 5% by mass at 20 ° C. When the water solubility of the organic solvent is 5% by mass or more, the aqueous phase is efficiently added when added to the mixture of the aqueous latex containing the rubber-like polymer particles (B) and the specific organic solvent. The effect of separating tends to be reduced.

  In addition, the water-soluble electrolyte is not particularly limited in structure, composition, and the like, and can be used without limitation as long as it has a water-solubility that does not precipitate during operation and become a contamination source. Specific examples include water-soluble alkali metal salts, alkaline earth metal salts, and ammonium salts. More specifically, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, potassium sulfate, Examples thereof include magnesium sulfate, sodium phosphate, potassium phosphate, calcium phosphate, ammonium sulfate, and inorganic acids such as hydrochloric acid and sulfuric acid. These can be used singly or in appropriate combination of two or more.

  When an aqueous latex and a non-mixable organic solvent are not added to a mixture of an aqueous latex and a specific organic solvent, and such a water-soluble electrolyte is not added, the aqueous phase is efficiently removed from the mixture. It may be relatively difficult to separate and remove.

  More preferably, prior to mixing the dispersion of the rubber-like polymer particles (B) thus obtained in an organic solvent with the alicyclic epoxy resin (A), the dispersion is water or water-soluble. Water-soluble impurities such as emulsifiers or dispersants used in the preparation of aqueous latex containing rubber-like polymer particles (B) by performing the operation of separating the aqueous phase one or more times after contacting with the aqueous electrolyte solution It is also possible to further reduce or eliminate.

  As a method for removing a volatile component containing an organic solvent from a mixture of the alicyclic epoxy resin (A) and the rubber-like polymer particles (B) thus obtained, a known method can be applied, for example, in a tank. Batch method of charging (depressurizing) the mixture, method of bringing the mixture into countercurrent contact with a dry gas in a tank, continuous method using a thin film evaporator, extrusion equipped with a devolatilizer Or a method using a continuous stirring tank. Conditions such as temperature and required time for removing the volatile component can be appropriately selected within a range in which the alicyclic epoxy resin (A) does not react or deteriorate the quality. Further, such a volatile component removing operation can be carried out after blending the above-described curing agent (C) or an additive according to the various uses for convenience of various uses.

[Hardened body]
The light transmittance of the cured product obtained by heating and curing the epoxy resin composition for optical element sealing material of the present invention is a wavelength of 400 nm in the thickness direction in a plate-shaped cured product having a thickness of 2 mm ± 0.2 mm. The light transmittance is required to be 70% or more, preferably the light transmittance is 75% or more, more preferably 80% or more.

Moreover, the ultraviolet-ray deterioration resistance of the cured product obtained by heat-curing the epoxy resin composition for optical element sealing material of the present invention is a plate-like cured product having a thickness of 2 mm ± 0.2 mm. Using a meter (manufactured by Suga Test Instruments Co., Ltd.), after irradiating with ultraviolet rays for 100 hours under the conditions of irradiation intensity of 0.4 kw / m ² and black panel temperature of 63 ° C. (in air atmosphere), it was removed from the tester and cured with epoxy After cooling the product to room temperature, the yellowness YI value (Yellow Index) measured using a color difference meter needs to be 40 or less, preferably this YI value is 35 or less, more preferably 30 or less. .

  Moreover, the heat-resistant deterioration property of the hardened | cured material obtained by heat-curing the epoxy resin composition for optical element sealing materials of this invention is the plate-shaped hardened | cured material of thickness 2mm +/- 0.2mm in oven (Air). In an atmosphere) after being left at 150 ° C. for 100 hours, taken out of the oven, the epoxy cured product is cooled to room temperature, and the yellowness YI (Yellow Index) measured using a color difference meter must be 50 or less Preferably, this YI value is 45 or less, more preferably 40 or less.

  As described above, in order to obtain a cured product excellent in light transmittance, UV resistance, and heat resistance, it is necessary to appropriately adjust the types and blending ratios of the aforementioned components.

  The cured product of the epoxy resin composition for optical element sealing material of the present invention is excellent in heat resistance, moisture resistance, light resistance, adhesion and transparency, and has sufficient strength without brittleness problems. It is useful as an LED sealing material that emits light of a short wavelength, especially for applications related to optical semiconductors such as LEDs and CCDs.

[Light emitting element]
The epoxy resin composition for an optical element sealing material of the present invention is effective in sealing a light emitting element that emits light having a relatively short wavelength with a peak wavelength of 350 to 550 nm because of excellent light resistance.

Such light-emitting elements include Group III nitrides of the periodic table formed by metal organic chemical vapor deposition (MOCVD), molecular beam crystal growth (MBE), and halide vapor deposition (HVPE). A compound compound semiconductor, which is represented by a general formula of Al _X Ga _Y In _1-XY N (0 ≦ X ≦ 1, 0 ≦ Y ≦ 1, 0 ≦ X + Y ≦ 1), and is a so-called Al _X , GaN and InN. Included are so-called ternary systems of binary systems, Al _x Ga _1-X N, Al _x In _1-X N and Ga _x In _1-X N (where 0 ≦ X ≦ 1). Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, a pn junction, or the like, a heterostructure, or a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used.

[Sealing method]
As a general method of sealing, a low-pressure transfer molding method can be mentioned, but sealing can also be performed by injection molding, compression molding, casting, potting, casting, screen printing or the like. Although the curing conditions at the time of molding and / or after molding vary depending on the type and blending amount of each component of the epoxy resin composition, the curing temperature is preferably 50 to 200 ° C. and the curing time is preferably 1 minute to 10 hours.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples, and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following, “parts” and “%” respectively represent “parts by mass” and “mass%” (excluding “%” of physical properties).

  In the following, various evaluation methods are as follows.

<Measurement method of total chlorine content>
The total chlorine content of the epoxy resin is as follows: 0.1 g of the sample amount is dissolved in a mixed solvent of 12.5 ml of toluene / 12.5 ml of dimethyl cellosolve, 4 ml of biphenyl sodium is added, and the mixture is stirred at room temperature for 2 minutes. By titrating with a silver nitrate solution.

<UV resistance test (color difference measurement)>
An epoxy cured product produced in the same manner as the sample for measuring light transmittance was used with a metallizing vertical weather meter (manufactured by Suga Test Instruments Co., Ltd.), irradiation intensity 0.4 kw / m ² , black panel temperature 63 ° C. ( After irradiating with ultraviolet rays for 100 hours under the conditions of (air atmosphere), the product was taken out from the metallizing vertical weather meter, the epoxy cured product was cooled to room temperature, and then the yellowness YI value (Yellow Index) was measured using a color difference meter. The smaller this value, the better the resistance to UV degradation.

<Heat resistance deterioration test (color difference measurement)>
The cured epoxy product produced in the same manner as the sample for measuring light transmittance was left in an oven (in an Air atmosphere) at 150 ° C. for 100 hours, then removed from the oven, and the cured epoxy product was cooled to room temperature, followed by color difference. A yellowness YI value (Yellow Index) was measured using a meter. The smaller this value, the better the heat deterioration resistance.

<Light transmittance>
Two sheets were prepared by attaching a PET film to one side of a soft glass plate having a length of 20 cm, a width of 20 cm, and a thickness of 8 mm. One glass plate to which the film was attached was placed so that the film was on top, and a silicone tube having an outer diameter of 4 mm and an inner diameter of 2 mm was placed on the U-shape. Furthermore, place a metal plate with a thickness of 2 mm on the four corners of the glass plate, and stack another glass plate with a pre-made film on it so that the film is on the bottom. Fixed. The epoxy resin composition was poured therein and heated in an oven at 100 ° C. for 3 hours and then at 140 ° C. for 3 hours to obtain a cured product. The cured product having a thickness of 2 mm prepared by this method was cut into a 6 cm square with a diamond cutter, and light transmittance at a wavelength of 400 nm was measured using a Hitachi spectrophotometer UV Solutions U-2010 (Spectrophotometer) at 23 ° C. Was measured.

<Crack resistance test (heat crack test)>
A casting film was prepared by attaching a PET film with an adhesive to one side of a Teflon ring having an inner diameter of 28 mm, an outer diameter of 50 mm, and a thickness of 12.8 mm. The epoxy resin composition was poured therein, a hexagonal nut having an inner diameter of mm was immersed in the inner surface, and heated in an oven at 100 ° C. for 3 hours and then at 140 ° C. for 3 hours to obtain a cured product. Ten cured products prepared by this method are put in an oven set at 100 ° C. for 10 minutes and heated, and then the cured product is taken out of the oven and then immersed in an ethanol solution cooled to −40 ° C. with dry ice for 10 minutes. Cooling was performed. This was defined as one cycle, and 10 cycles were repeated to examine the number of cured products in which cracks occurred among the 10 cured products.

<Glass dislocation point Tg>
It was measured by the TMA method (temperature rising at 5 ° C./min).

<Izod impact strength>
It measured according to JIS-K-6911.

<Tensile shear adhesive strength>
According to JIS-K-6850, the iron-iron tensile shear bond strength was measured.

<Hygroscopic rate>
It is a moisture absorption rate after leaving a cured test piece (a disk having a diameter of 50 mm and a thickness of 3 mm) at 121 ° C. and 100% RH for 24 hours, and is calculated by the following formula.
Moisture absorption rate = {(mass of test piece after 24 hours in constant temperature and humidity chamber at 121 ° C. and 100% RH
-Mass of test piece before treatment) / Mass of test piece before treatment} x 100

[Production Example 1: Production of rubber-like polymer particle (Bi) latex]
In a pressure-resistant polymerizer, 200 parts of water, 0.03 part of tripotassium phosphate, 0.25 part of potassium dihydrogen phosphate, 0.002 part of ethylenediaminetetraacetic acid, 0.001 part of ferrous sulfate and dodecylbenzenesulfonic acid After adding 1.5 parts of sodium and sufficiently replacing the nitrogen with stirring to remove oxygen, 75 parts of butanediene and 25 parts of styrene were introduced into the system, and the temperature was raised to 45 ° C. Thereto was added 0.015 part of paramentane hydroperoxide, followed by 0.04 part of sodium formaldehyde sulfoxylate to initiate polymerization. Four hours after the start of polymerization, 0.01 part of paramentane hydroperoxide, 0.0015 part of ethylenediaminetetraacetic acid and 0.001 part of ferrous sulfate were added. At 10 hours after the polymerization, the residual monomer was removed by evaporation under reduced pressure to complete the polymerization. The polymerization conversion was 98%, and the volume average particle size of the obtained styrene-butadiene rubber latex was 0.1 μm.

  In a 3 L glass container, 1300 g of the obtained rubber latex (including 420 g of styrene / butadiene rubber particles and 1.5% by weight sodium dodecylbenzenesulfonate as a solid content of rubber as an emulsifier) and 440 g of pure water The mixture was charged and stirred at 70 ° C. while replacing with nitrogen. After 1.2 g of azobiisobutyronitrile (AIBN) was added, a mixture of 54 g of styrene, 72 g of methyl methacrylate, 36 g of acrylonitrile and 18 g of glycidyl methacrylate was continuously added over 3 hours, followed by graft polymerization. After completion of the addition, the reaction was terminated by further stirring for 2 hours to obtain a latex of rubber-like polymer particles (B). The polymerization conversion rate was 99.5%. The obtained latex was used as it was.

[Production Example 2: Dispersion of rubber-like polymer particles (Bi) latex]
340 g of methyl ethyl ketone (water solubility at 20 ° C., 9.99) was introduced into a 1 L mixing tank kept at 25 ° C., and the aqueous latex of rubber-like polymer particles (Bi) of Production Example 1 was stirred. 252 g was charged. After uniformly mixing, 126 g of water was added, 30 g of 5% sodium sulfate aqueous solution was added with stirring, the organic solvent layer and the aqueous layer were separated, and the aqueous layer was discharged. The total amount of rubber-like polymer particles (Bi) contained in the water layer was 0.1% or less with respect to the total amount of rubber-like polymer particles (Bi). Next, the organic solvent layer was alicyclic epoxy resin (Ai) “YX8034” (trade name of Japan Epoxy Resin; epoxy resin hydrogenated with bisphenol A type epoxy resin, hydrogenation rate of about 100%, epoxy equivalent; 290 g After mixing with 306 g / equivalent), the volatile component was distilled off under reduced pressure using a vacuum pump to obtain an epoxy resin composition containing rubber-like polymer particles (Bi). As a result of observing the dispersion state of the rubber-like polymer particles (Bi) in the cured product obtained from this epoxy resin composition, it was uniformly dispersed without aggregation.

  This epoxy resin composition contains 25 parts of rubbery polymer particles (Bi) in a total of 100 parts of alicyclic epoxy resin (Ai) and rubbery polymer particles (Bi). It is a waste.

[Production Example 3: Production of core-shell type rubbery polymer particles (B-ii) latex]
(A) Production of crosslinked methacrylic polymer (innermost layer) In a glass reactor, 220 parts of ion-exchanged water, 0.3 part of boric acid, 0.03 part of sodium carbonate, 0.09 part of sodium N-lauroyl sarcosinate, After charging 0.09 part of sodium formaldehyde sulfoxylate, 0.006 part of sodium ethylenediaminetetraacetate and 0.002 part of ferrous sulfate heptahydrate and heating to 80 ° C. with stirring in a nitrogen stream, methacrylic acid 25% of the mixed solution of the innermost layer component consisting of 25 parts of methyl and 0.1 part of allyl methacrylate was charged all at once and polymerized for 45 minutes.
Subsequently, the remaining 75% of the innermost layer component mixture was continuously added over a period of time. After completion of the addition, the polymerization was completed by maintaining at the same temperature for 2 hours. During this period, 0.2 part of sodium N-lauroyl sarcosinate was added. The average particle size of the polymer particles in the obtained innermost crosslinked methacrylic polymer latex was 160 nm (determined using light scattering at a wavelength of 546 nm), and the polymerization conversion rate ((polymer production amount) / Monomer charge amount) × 100 (%)) was 98%.

(B) Production of acrylic rubber After maintaining the crosslinked methacrylic latex polymer obtained in the above production (a) at 80 ° C. in a nitrogen stream and adding 0.1 part of potassium persulfate, n-butyl acrylate 41 A monomer mixture consisting of 1 part, 9 parts of styrene and 1 part of allyl methacrylate was continuously added over 5 hours. During this time, 0.1 part of potassium oleate was added in three portions. After completing the addition of the monomer mixture, 0.05 part of potassium persulfate was further added and held for 2 hours in order to complete the polymerization. The average particle diameter of acrylic rubber particles in the obtained latex polymer was 230 nm (determined by a light scattering method), and the polymerization conversion rate was 99%.

(C) Production of core-shell type polymer The rubbery latex polymer obtained in the production (b) was kept at 80 ° C., 0.02 part of potassium persulfate was added, 24 parts of methyl methacrylate, and n-butyl acrylate. A mixture of 1 part and 0.1 part of t-dodecyl mercaptan was added continuously over 1 hour. After completion of the addition of the monomer mixture, the mixture was held for 1 hour to obtain core-shell type rubbery polymer particles (B-ii) composed of a multilayer structure graft copolymer latex polymer. The average particle diameter of the multilayer graft copolymerized latex polymer particles was 253 nm (determined by a light scattering method), and the polymerization conversion rate was 99%.
The obtained multilayer structure graft copolymer latex polymer was used as it was.

[Production Example 4: Core-shell type rubber-like polymer particle (B-ii) latex dispersion]
340 g of methyl ethyl ketone (solubility of water at 20 ° C., 9.99) was introduced into a 1 L mixing tank maintained at 25 ° C., and 200 g of the multilayer structure graft copolymer latex polymer obtained in Production Example 3 was added while stirring. did. After uniformly mixing, 126 g of water was added, 30 g of 5% sodium sulfate aqueous solution was added with stirring, the organic solvent layer and the aqueous layer were separated, and the aqueous layer was discharged. The total amount of rubber-like polymer particles (B-ii) contained in the water layer was 0.1% or less with respect to the total amount of rubber-like polymer particles (B-ii). Then, the organic solvent layer was alicyclic epoxy resin (Ai) YX8034 (trade name of Japan Epoxy Resin Co .; epoxy resin hydrogenated with bisphenol A type epoxy resin, hydrogenation rate of about 100%, epoxy equivalent; 290 g / equivalent ) After mixing with 330 g, the volatile component was distilled off under reduced pressure using a vacuum pump to obtain an epoxy resin composition containing core-shell type rubbery polymer particles (B-ii). As a result of observing the dispersion state of the core-shell type rubber-like polymer particles (B-ii) in the cured product obtained from this epoxy resin composition, it was uniformly dispersed without aggregation.

  This epoxy resin composition comprises the core-shell type rubbery polymer particles (B-ii) in 100 parts in total of the alicyclic epoxy resin (Ai) and the core-shell type rubbery polymer particles (B-ii). Includes 25 parts.

[Production Example 5: Production of modified acid anhydride]
Into a 1 L glass flask equipped with a stirrer, a thermometer and a condenser tube, 165 g of acid anhydride curing agent “Licacid MH-700” (trade name of Shin Nippon Rika Co., Ltd .; methyl hexahydrophthalic anhydride), ethylene ether glycol 2 g was charged and heated to 130 ° C. with stirring. After the liquid temperature reached 130 ° C., the mixture was allowed to react for 2 hours to obtain about 170 g of the intended acid anhydride glycol-modified product. As a result of analysis, the viscosity at 25 ° C. was 380 mPa.s.

[Example 1]
Epoxy resin (Ai) composition containing 80 parts of hydrogenated aromatic epoxy resin “YX8034” as the alicyclic epoxy resin (Ai) and rubber-like polymer particles (Bi) obtained in Production Example 2 20 parts of a product, 0.2 part of an ultraviolet absorber (HMB: 2-hydroxy-4-methoxybenzophenone), 0.2 part of an antioxidant (BHT: 2,6-di-t-butyl-p-cresol) at a temperature of 80 After mixing at 0 ° C. until uniform, 55 parts of “Ricacid MH-700” (trade name of Shin Nippon Rika Co., Ltd .; methyl hexahydrophthalic anhydride) was further added as an acid anhydride curing agent, and mixed until uniform. Then, 0.5 parts of “Hishicolin PX-4MP” (trade name of Nippon Chemical Industry Co., Ltd .; methyltributylphosphonium dimethyl phosphate) was added as a curing accelerator, stirred and dissolved to obtain an epoxy resin composition.
After defoaming this composition under reduced pressure, it was poured into a sample mold required for evaluation, and heated in an oven at 100 ° C. for 3 hours and then at 140 ° C. for 3 hours to obtain an epoxy cured product. It was. The physical property values of this epoxy cured product are shown in Table 1.

[Examples 2 to 6 and Comparative Examples 1 to 5]
Except changing the compounding ratios of an epoxy resin, an acid anhydride curing agent, a curing accelerator, and other additives as shown in Table 1, the same operation as in Example 1 was performed to obtain an epoxy cured product. Table 1 shows the physical property values of the obtained epoxy cured product.

In the table, details of the components used are as follows.
Hydrogenated aromatic epoxy resin (AI) “YX8034”; hydrogenated bisphenol A type epoxy resin, epoxy equivalent 290 g / equivalent, total chlorine content 0.14% by mass (manufactured by Japan Epoxy Resin Co., Ltd.)
Hydrogenated aromatic epoxy resin (A-ii) “YX8000”; hydrogenated bisphenol A type epoxy resin, epoxy equivalent 205 g / equivalent, total chlorine content 0.15 mass% (manufactured by Japan Epoxy Resin Co., Ltd.)
Aromatic epoxy resin “jER828”; bisphenol A type epoxy resin, epoxy equivalent 190 g / equivalent (manufactured by Japan Epoxy Resin Co., Ltd.)
Alicyclic epoxy resin (A-iii) “171D” obtained by epoxidizing cyclic olefin; 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, epoxy equivalent 130 g / equivalent, total chlorine contained 0.01g / equivalent or less (Japan Epoxy Resin Co., Ltd.)
Acid anhydride “MH-700”; methyl hexahydrophthalic anhydride (manufactured by Shin Nippon Chemical Co., Ltd.)
Cationic polymerization initiator “SI-100L”; aromatic sulfonium salt (manufactured by Sanshin Chemical Co., Ltd.)
Curing accelerator “PX-4MP”; methyltributylphosphonium dimethyl phosphate (manufactured by Nippon Chemical Industry Co., Ltd.)
Ultraviolet absorber (HMB): 2-hydroxy-4-methoxybenzophenone antioxidant (BHT); 2,6-di-t-butyl-p-cresol

  From Table 1, it can be seen that the epoxy resin composition for an optical element sealing material of the present invention is excellent in balance in transparency, light resistance, heat resistance, weldability, moisture resistance, and impact resistance.

Claims (11)

The following (A) component, (B) component and (C) component are contained, the content of (A) component is 100-50 mass% with respect to all the epoxy resin components, and content of (B) component is 1 to 50% by mass with respect to all epoxy resin components,
An epoxy resin composition for an optical element sealing material, wherein a cured product having a thickness of 2 mm ± 0.2 mm has a light transmittance of 70% or more at a wavelength of 400 nm.
(A) component; alicyclic epoxy resin (B) component; rubber-like polymer particle (C) component; one selected from the group consisting of an acid anhydride, a modified acid anhydride, and a cationic polymerization initiator Two or more curing agents.   The (A) component alicyclic epoxy resin is one or more epoxy resins selected from the group consisting of epoxy resins obtained by epoxidizing cyclic olefins and epoxy resins obtained by hydrogenating aromatic epoxy resins. The epoxy resin composition for optical element sealing materials of Claim 1 characterized by the above-mentioned.   (A) component cycloaliphatic epoxy resin is 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, epoxy resin obtained by hydrogenating bisphenol A type epoxy resin, bisphenol F type epoxy resin The optical element encapsulating according to claim 2, wherein the optical element is selected from the group consisting of an epoxy resin obtained by hydrogenating an epoxy resin and an epoxy resin obtained by hydrogenating a biphenol type epoxy resin. Epoxy resin composition for fastening materials. The rubber-like polymer particles of the component (B) graft-polymerize 5 to 50% by mass of the shell layer of the following (Ba-2) with respect to 50 to 95% by mass of the rubber particle core of the following (Ba-1). The epoxy resin composition for an optical element sealing material according to any one of claims 1 to 3, wherein the rubber-like polymer particles (Ba) are obtained.
(Ba-1): 50% by mass or more of at least one monomer selected from the group consisting of a diene monomer and a (meth) acrylate monomer, and other copolymerizable vinyl monomers 50 used as necessary Rubber particle core made of rubber elastic body, polysiloxane rubber-based elastic body, or a mixture thereof composed of mass% or less (Ba-2): (meth) acrylic acid ester, aromatic vinyl compound, and vinyl cyanide compound Shell layer made of a polymer obtained by (co) polymerizing one or more selected from the group consisting of   In the presence of (Bb-1) acrylic rubber and / or conjugated diene rubber, (Bb-2) (meth) acrylic acid ester 70-100% by mass, It is rubber-like polymer particles (Bb) obtained by (co) polymerizing a monomer component consisting of 0 to 30% by mass of a vinyl group monomer and 0 to 30% by mass of other copolymerizable monomers. Item 4. The epoxy resin composition for optical element sealing materials according to any one of Items 1 to 3.   The curing agent of component (C) is one or more selected from the group consisting of hexahydrophthalic anhydride and glycol-modified products thereof, methylhexahydrophthalic anhydride and glycol-modified products thereof, and onium salts. The epoxy resin composition for optical element sealing materials of any one of Claims 1 thru | or 5 characterized by these. Furthermore, the following (D) component and / or (E) component are contained 0.01-10 mass% with respect to all the epoxy resin components, respectively, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. Epoxy resin composition for optical element sealing material.
(D) component; 1 type, or 2 or more types of antioxidant chosen from the group which consists of a phenolic antioxidant, sulfur type antioxidant, and phosphorus antioxidant (E) component; UV absorber   The rubber-like polymer particles of component (B) are dispersed in the whole or part of the epoxy resin component, and then mixed with other components to produce the component. Item 4. An epoxy resin composition for an optical element sealing material according to the item.   The epoxy resin composition for optical element sealing materials according to any one of claims 1 to 8, wherein the optical element is a light emitting element having a main light emission peak at a wavelength of 350 to 550 nm.   The epoxy resin composition for optical element sealing materials according to any one of claims 1 to 9, wherein the optical element is a light emitting diode (LED).   An epoxy resin cured body obtained by curing the epoxy resin composition for optical element sealing materials according to claim 1.