JP2017082027A - Curable epoxy resin composition for primarily encapsulating photocoupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-conductive composition, a heat-releasing grease, a paste, a pad, a sheet, and a film improved dramatically in heat conductivity in a heat-transferring direction.SOLUTION: A curable epoxy resin composition for primarily encapsulating a photocoupler includes: 100 mass pts. of prepolymer (A) having a ratio of 0.6-2.0 of an epoxy group equivalent to an acid anhydride group equivalent, which is a reaction product of an epoxy resin (A-1) being solid or having no fluidity at 25°C with acid anhydride (A-2); 80-1,000 mass pts. of an inorganic filler (B); 0.05-5 mass pts. of a hardening accelerator (C) comprising an onium salt represented by the following formula (1): XY(1) where in the formula (1), Xis a cation such as an aliphatic quaternary phosphonium ion, and Yis an inion such as a tetrafluoroborate ion; 0.01-10 mass pts. of 1 or not less than 2 of antioxidants (D) selected from phenolic, phosphorus, and sulfur antioxidants; and 1-10 mass pts. of a hydrotalcite-like compound and/or a calcined product of the hydrotalcite-like compound (E).SELECTED DRAWING: None

Description

  The present invention relates to a thermosetting epoxy resin composition for primary encapsulation of a photocoupler and an optical semiconductor device using the same.

  A photocoupler is a device that combines a light-emitting element and a light-receiving element that converts an input electric signal into light by a light-emitting element and transmits the light to the light-receiving element. For this reason, it is important to efficiently transmit light from the light emitting side to the light receiving side. Moreover, it often has a double structure in order to block light from the outside and impart moisture resistance reliability and flame retardancy. That is, the light emitting element is sealed with a primary sealing resin having light transmission ability, and subsequently sealed with a secondary sealing resin having a light shielding property. Conventionally, a silicone resin has been used for the primary sealing resin, and an epoxy resin has been used for the secondary sealing resin. On the other hand, in recent years, for the purpose of cost reduction, only the periphery of a light receiving element or a light emitting element is sealed with a silicone resin, and then an epoxy resin is applied as a primary sealing resin.

  The efficiency of the photocoupler is expressed by CTR (Current Transfer Ratio) and can be obtained by the ratio of the current on the light emitting side and the electromotive force on the light receiving side. In order to obtain a high CTR value, the light transmittance of the resin composition, particularly high light transmittance in the near-infrared light in the vicinity of 700 nm to 1,000 nm is necessary.

  Patent Document 1 discloses that an epoxy resin composition excellent in reliability and light transmittance is used for a photocoupler. In order to obtain high CTR, it has been shown that reduction of light absorption by metallic substances and light scattering by fused spherical silica are important. However, as the performance of photocouplers has improved, it has been used as an inorganic filler. In the case of fused spherical silica, the light transmission of the resin composition is improved by certainly increasing the light scattering, but the refractive index of the resin component such as fused silica and epoxy resin and curing agent rich in aromatics is large. Since it is far away, the resin composition using the resin composition does not have sufficient light transmission.

  In order to obtain high transmittance even if inorganic filler is contained due to moldability and low thermal expansion coefficient, the refractive index of resin component and inorganic filler is made close, or a specific range of inorganic filler and epoxy resin Patent Documents 2 and 3 exemplify premixing with acid and acid anhydrides. However, the curing agent used in Patent Document 2 uses an aromatic compound such as a phenol novolak or a cresol novolak curing agent. In recent years, since the output of light emitting elements has been increased and the usage environment has shifted to a high temperature side, the primary sealing resin has been severely degraded, and the CTR has decreased due to coloring and the like, and satisfactory results cannot be obtained. In addition, the composition disclosed in Patent Document 3 is often obtained as a paste and has a problem in handling properties.

  Furthermore, it is common to use a GaAs chip as a light emitting element used in such a photocoupler. However, this GaAs is weak against acids, such as acid anhydrides and derivatives thereof used as curing agents for epoxy resins. Recently, the problem of chip destruction due to coexistence with acidic materials has become a problem.

  Patent Documents: Epoxy resin compositions that combine hydrotalcite compounds and hindered amine antioxidants (light stabilizers) to obtain excellent high-temperature storage properties without impairing flame retardancy, moldability, and curability 4 is a composition substantially using a phenol curing agent. When used in an acid anhydride curing agent, a hindered amine antioxidant acts as a curing accelerator, and the composition gels during blending and production. It has been found that not only there is a risk of causing scumming, but also heat resistance discoloration is poor, and it causes mold stains.

Japanese Patent Laid-Open No. 62-108583 JP-A-6-25386 JP 2011-37996 A Japanese Patent No. 5,540,485

  An object of the present invention is to obtain a thermosetting epoxy resin composition for primary sealing of a photocoupler that has excellent handling properties and excellent reliability including heat resistance and light resistance, and a photocoupler device using the same. .

  As a result of intensive studies, the present inventors have found that a resin composition having the following composition solves the above problems, and completed the present invention.

  That is, the present invention provides the following thermosetting epoxy resin composition for primary encapsulation of a photocoupler and a photocoupler primary-sealed thereby.

[1]
(A) (A-1) A reaction product of an epoxy resin that is not solid or fluid at 25 ° C. and (A-2) an acid anhydride, which is an epoxy group equivalent / an acid anhydride group equivalent. Is a ratio of 0.6 to 2.0: 100 parts by mass,
(B) Inorganic filler: 80 to 1,000 parts by mass,
(C) The following formula (1):
X ⁺ Y ⁻ (1)
[In the formula (1), X ⁺ represents an aliphatic quaternary phosphonium ion, an aromatic quaternary phosphonium ion, an onium ion of 1,8-diaza-bicyclo [5.4.0] undecan-7-ene, and an imidazole derivative. Y ⁻ represents a tetrafluoroborate ion, a tetraphenylborate ion, a hexafluorophosphate ion, a bistrifluoromethylsulfonylimido ion, or a tris (trifluoromethylsulfonyl) carbonate ion. , An anion selected from trifluoromethanesulfonate ion, halogenated acetate ion, carboxylate ion and halogen ion. ]
Curing accelerator comprising an onium salt represented by: 0.05 to 5 parts by mass,
(D) One or more antioxidants selected from phenol-based, phosphorus-based and sulfur-based antioxidants: 0.01 to 10 parts by mass and (E) hydrotalcite-like compound and / or hydrotalcite Baked product of like compound: A thermosetting epoxy resin composition for primary sealing of a photocoupler, containing 1 to 10 parts by mass.

[2]
The thermosetting epoxy resin composition for primary sealing of a photocoupler according to [1], wherein the inorganic filler of component (B) is spherical silica or glass particles.
[3]
The thermosetting epoxy resin composition for primary encapsulation of a photocoupler according to [1] or [2], wherein the curing accelerator of component (C) is a quaternary phosphonium salt.

[4]
The hydrotalcite-like compound of component (E) is represented by the following formula (2)
^{_{[M 2+ 1-x M 3+}} x (OH) 2] x + [(A n- x / n) · mH 2 O] x- (2)
^{(Wherein, M 2+} is a divalent metal ^{ion, M 3+} is a trivalent metal ^{ion, A n-is} an n-valent anion, x is the number of the range of 0 <x <1, m Represents a number from 0 to 10.)
The hydrotalcite-like compound fired product is represented by the following formula (3):
M ²⁺ _1-x M ³⁺ xO _{1 + x / 2} (3)
(X is a number in the range 0 <x <1)
The thermosetting epoxy resin composition for primary sealing of a photocoupler according to any one of [1] to [3], which is a compound represented by:

[5]
[1] A photocoupler that is primarily sealed with the thermosetting epoxy resin composition according to any one of [4].

  The thermosetting epoxy resin composition for primary sealing of a photocoupler of the present invention is useful for a photocoupler device because of excellent handling properties and excellent reliability including heat resistance and light resistance.

  Hereinafter, although the thermosetting epoxy resin composition for primary sealing of the photocoupler of the present invention will be described in detail, the present invention is not limited to these.

(A) (A-1) Reaction product of epoxy resin not solid or fluid at 25 ° C. and (A-2) acid anhydride (A) By containing component (A) as a resin component, heat A semiconductor light-emitting device that suppresses yellowing of a cured product of the curable epoxy resin composition and has little deterioration with time is realized. Moreover, when it becomes solid, handling of the thermosetting epoxy resin manufactured by kneading | mixing etc. becomes easy.

(A-1) Epoxy resin which does not have solid or fluidity at 25 ° C. This epoxy resin is an epoxy resin which does not have solid or fluidity at 25 ° C. mainly from the viewpoint of handleability. Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol type epoxy resins, or 4,4′-. Biphenol type epoxy resin such as biphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, naphthalenediol type epoxy resin, trisphenylol methane type epoxy resin, tetrakisphenylol ethane type Epoxy resin, triphenolalkane type epoxy resin, aralkyl type epoxy resin, biphenyl skeleton-containing aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, heterocyclic type epoxy resin, naphthalene ring containing epoxy resin Stilbene type epoxy resin, triazine derivative epoxy resin, alicyclic epoxy resin, epoxy resin hydrogenated aromatic ring, silicone-modified epoxy resin, etc., one of which is used alone or two or more of them are used. Can be used together.

  Among them, the use of bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, triazine derivative epoxy resin, epoxy resin with hydrogenated aromatic ring or silicone modified epoxy resin in terms of heat resistance and light resistance Among the triazine derivative epoxy resins, 1,3,5-triazine nucleus derivative epoxy resins are more preferable. In particular, an epoxy resin having an isocyanurate ring is excellent in light resistance and electrical insulation, and desirably has a divalent, more preferably a trivalent epoxy group per one isocyanurate ring. Specific examples include tris (2,3-epoxypropyl) isocyanurate, tris (α-methylglycidyl) isocyanurate, and tris (α-methylglycidyl) isocyanurate.

  The melting point or softening point of the epoxy resin that does not have solid or fluidity at 25 ° C. used in the present invention is preferably 40 to 125 ° C.

(A-2) Acid anhydride The acid anhydride of the component (A-2) used in the present invention acts as a curing agent, is non-aromatic for improving heat resistance and light resistance, and Those having no carbon-carbon double bond are preferred, and examples thereof include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, and hydrogenated methylnadic anhydride. Among these, Hexahydrophthalic anhydride and / or methylhexahydrophthalic anhydride are preferred. These acid anhydride curing agents may be used alone or in combination of two or more.

  When the component (A) is configured as a combination of (A-1) an epoxy resin that does not have solidity or fluidity at 25 ° C. and (A-2) an acid anhydride, (A-2) As a compounding quantity of an acid anhydride, the total epoxy group of the epoxy resin which does not have solid or fluidity | liquidity at (A-1) 25 degreeC with respect to 1 mol of above-mentioned (A-2) acid anhydride groups is 0. 0.6 to 2.0 mol, preferably 0.8 to 1.9 mol, more preferably 0.9 to 1.8 mol. If (the total number of moles of epoxy groups) / (the number of moles of acid anhydride) is less than 0.6, the unreacted curing agent may remain in the cured product, which may deteriorate the moisture resistance of the resulting cured product. On the other hand, if it is 2.0 or more, poor curing may occur and reliability may be lowered.

  As a method for producing a prepolymer which is a reaction product of component (A), that is, (A-1) an epoxy resin which is not solid or fluid at 25 ° C. and (A-2) acid anhydride, (A-1) An epoxy resin which is not solid or fluid at 25 ° C. and (A-2) an acid anhydride [epoxy group of (A-1) component] / [(A-2) component The acid anhydride group has a molar ratio of 0.6 to 2.0, and heating and mixing may be mentioned, but the reaction is carried out in the presence of the same curing accelerator as described later as component (C). To obtain a solid product (ie, prepolymer). At this time, the solid product is preferably made into a fine powder state by pulverization or the like. The particle diameter of the fine powder is preferably in the range of 5 μm to 3 mm. The molar ratio of the epoxy group of the component (A-1) to the acid anhydride group of the component (A-2) is preferably 0.9 to 1.8. If this molar ratio is less than 0.6, an unreacted curing agent may remain in the cured product and deteriorate the moisture resistance of the resulting cured product. On the other hand, if it is 2.0 or more, poor curing may occur and reliability may be lowered.

The detailed reaction conditions for the prepolymer synthesis are as follows. The component (A-1) and the component (A-2) are reacted at 60 to 120 ° C., preferably 70 to 110 ° C. for 4 to 20 hours, preferably 6 to 15 hours. Alternatively, the curing accelerators of the component (A-1), the component (A-2) and the component (C) are previously added at 30 to 80 ° C., preferably 40 to 70 ° C. for 2 to 12 hours, preferably 3 to 8 hours. Let react for hours.
Thus, the prepolymer is obtained as a solid product having a softening point of 40 to 100 ° C., preferably 45 to 70 ° C. In order to mix this with the composition of the present invention, it is preferable to make it fine powder by pulverization or the like. If the softening point of the substance obtained by the reaction is less than 40 ° C., it does not become a solid, and if it exceeds 100 ° C., there is a possibility that the fluidity required at the time of molding as a composition cannot be obtained.

(B) Inorganic filler An inorganic filler is mix | blended with the thermosetting epoxy resin composition of this invention. As such an inorganic filler, what is normally mix | blended with an epoxy resin composition is mentioned. For example, silicas such as fused silica and crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, antimony trioxide, glass particles and the like can be mentioned. From the viewpoint of close refractive index and fluidity, spherical silica and Glass particles are desirable. Although the average particle diameter and shape of these inorganic fillers are not particularly limited, those having an average particle diameter of 3 to 50 μm are preferable. The average particle diameter can be determined as a cumulative weight average value D _{50 (or} median diameter) in particle size distribution measurement by laser diffraction method.

  In particular, fused spherical silica and spherical glass particles are preferably used as the inorganic filler, and in view of moldability, fluidity, burrs, and transmittance, fused spherical silica is preferred, and the average particle size is 5 to 30 μm. In particular, 7 to 25 μm is preferable. If the average particle size is less than 5 μm, the viscosity is greatly increased, the fluidity is lowered, and the transmittance may be lowered. If the average particle size is larger than 30 μm or the maximum particle size is larger than 53 μm, many burrs may occur. Moreover, in order to obtain high fluidization, it is preferable to use a combination of a fine region of 0.1 to 3 μm, a medium particle size region of 4 to 8 μm, and a coarse region of 10 to 50 μm.

The inorganic filler of the component (B) increases the bonding strength with the resin component of the component (A), improves the adhesion between the inorganic filler and the resin component, increases the strength of the molded product, For the purpose of preventing attenuation, the surface may be pretreated with a coupling agent such as a silane coupling agent or a titanate coupling agent.
Examples of such a coupling agent include epoxy functions such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. It is preferable to use a mercapto functional alkoxysilane such as a functional alkoxysilane or γ-mercaptopropyltrimethoxysilane. The blending amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited, but the treatment filler does not discolor when left at 150 ° C. or more like many amine functional alkoxysilanes. Those are preferred.

  (B) The compounding quantity of the inorganic filler which is a component is 80-1,000 mass parts with respect to 100 mass parts of (A) component, and 200-800 mass parts is especially preferable. If it is less than 80 parts by mass, sufficient strength may not be obtained. If it exceeds 1,000 parts by mass, unfilled defects due to thickening and flexibility will be lost, resulting in defects such as peeling in the element. May occur. In addition, it is preferable to make the compounding quantity of the inorganic filler which is this (B) component into the range of 10-92 mass% of the whole composition, especially 50-88 mass%.

(C) Curing accelerator The curing accelerator of the component (C) is blended to accelerate curing of the thermosetting epoxy resin composition of the present invention. As the curing accelerator, a curing accelerator composed of an onium salt represented by the following formula (1) is used.

X ⁺ Y ⁻ (1)

[In the formula (1), X ⁺ represents an aliphatic quaternary phosphonium ion, an aromatic quaternary phosphonium ion, an onium ion of 1,8-diaza-bicyclo [5.4.0] undecan-7-ene, and an imidazole derivative. Y ⁻ represents a tetrafluoroborate ion, a tetraphenylborate ion, a hexafluorophosphate ion, a bistrifluoromethylsulfonylimido ion, or a tris (trifluoromethylsulfonyl) carbonate ion. , An anion selected from trifluoromethanesulfonate ion, halogenated acetate ion, carboxylate ion and halogen ion. ]

  As a hardening accelerator which consists of onium salt represented by the said Formula (1), a quaternary phosphonium salt is preferable and a quaternary phosphonium bromide is more preferable from a viewpoint of heat resistance, light resistance, and few impurities.

  The compounding quantity of a hardening accelerator is 0.05-5 mass parts with respect to 100 mass parts of (A) component, and it is especially preferable to set it as the range of 0.1-2.0 mass parts. If it is out of the above range, the balance of heat resistance and moisture resistance of the cured product of the epoxy resin composition may be deteriorated, or curing at the time of molding may be very slow or fast.

(D) Antioxidant The thermosetting epoxy resin composition of this invention mix | blends (D) antioxidant for the initial stage transmittance | permeability improvement and long-term transmittance | permeability maintenance. (D) As an antioxidant of a component, it is characterized by using 1 type, or 2 or more types of antioxidant chosen from a phenol type, phosphorus type | system | group, sulfur type antioxidant, and as a specific example of antioxidant. Include the following antioxidants.

  Examples of phenolic antioxidants include 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, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] 2,4,8,10-tetraoxaspiro [ 5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-t-butyl-4-hydroxybenzyl) benzene and the like.

  Phosphorus antioxidants include triphenyl phosphite, diphenylalkyl phosphite, phenyl dialkyl phosphite, tri (nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, triphenyl phosphite , Distearyl pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, diisodecylpentaerythritol diphosphite, di (2,4-di-tert-butylphenyl) pentaerythritol diphosphite , Tristearyl sorbitol triphosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenyldiphosphonate, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) ) -2,4,8,10-teto Oxa-3,9-diphosphaspiro [5,5] undecane and 3,9-bis (octadecyloxy) 2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] An undecane etc. are mentioned.

  Examples of sulfur-based antioxidants include diuraryl thiopropionate, distearyl thiopropionate, dibenzyl disulfide, and trisnonylphenyl phosphite.

These antioxidants can be used alone or in combination of two or more. The compounding quantity of antioxidant is 0.01-10 mass parts with respect to 100 mass parts of (A) component, and it is preferable to set it as 0.1-8 mass parts especially. If the amount is too small, sufficient heat resistance may not be obtained and discoloration may occur, while if too large, curing inhibition may occur, and sufficient curability and strength may not be obtained.
Of these antioxidants, phosphorus-based antioxidants are preferably used, and among them, 3,9-bis (octadecyloxy) 2,4,8,10-tetraoxa-3,9-diphosphaspiro. [5,5] Undecane is particularly preferably used.

(E) Hydrotalcite-like compound and / or calcined product of hydrotalcite-like compound The thermosetting epoxy resin composition of the present invention traps anions such as carbonyl ions or neutralizes the pH of the composition. (E) A fired product of a hydrotalcite-like compound and / or a hydrotalcite-like compound is added. Examples of the hydrotalcite-like compound include layered double hydroxides represented by the following composition formula (2).

^{_{[M 2+ 1-x M 3+}} x (OH) 2] x + [(A n- x / n) · mH 2 O] x- (2)

In the above formula (2), M ²⁺ is a divalent metal ion such as Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Mn ²⁺ , and M ³⁺ is Al ³⁺ , Fe ³⁺ , Cr ³⁺ is a trivalent metal ion such ^{as, a n-is _{OH -, Cl -, CO 3}} 2-, which is an n-valent anion such as _SO ^{4 2-.} x is a numerical value of 0 <x <1, particularly 0.10 to 0.50, more preferably 0.20 to 0.33, and m is a numerical value in the range of 0 to 10, particularly 0. It is -8, Furthermore, it is 0-4.

  The fired product of the hydrotalcite-like compound is, for example, a double oxide that can be represented by the following general formula (3).

M ²⁺ _1-x M ³⁺ xO _{1 + x / 2} (3)

  In the above formula (3), x is a positive number.

In addition, as the component (E) of the present invention, a zinc-modified hydrotalcite compound such as Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .wH ₂ O, Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ may be used. Yes (w is a real number).

The hydrotalcite-like compound of component (E) and the fired product of the hydrotalcite-like compound have anion exchange ability. Therefore, a chip such as GaAs used as a light emitting element is protected by capturing carbonyl ions such as formate ion and acetate ion derived from component (A) or bringing the pH of the cured product close to neutral. It is something that can be done.

  The component (E) of the present invention is preferably a hydrotalcite compound represented by the following general formula (4) and / or a fired product of the hydrotalcite compound.

Mg _a Al _b (OH) _c CO ₃ .nH ₂ O (4)

  In the above formula (4), a, b, and c are numbers greater than 0 that satisfy 2a + 3b−c = 2, and n is a number that satisfies 0 ≦ n ≦ 4.

Examples of the hydrotalcite compound represented by the above formula (4) include Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ , Mg ₄ Al ₂ (OH) ₁₂ CO ₃ .3.5H ₂ O, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O, Mg ₃ Al _{2 (OH) 10 CO 3 ·} 1.7H 2 O , and the like. As commercial products, trade names “DHT-4A”, “DHT-4A-2”, “DHT-4C”, “DHT-6”, “Kyoward 500” (all manufactured by Kyowa Chemical Industry Co., Ltd.) “STABIACE HT” -1 "," STABIACE HT-7 "," STABIACE HT-P "(manufactured by Sakai Chemical Industry), and the like.

  (E) The compounding quantity of a component is 1-10 mass parts with respect to 100 mass parts of (A) component, Preferably it is 2-8 mass parts. If the amount of the component (E) is less than the lower limit, the effect cannot be obtained sufficiently. Moreover, when the quantity of (E) component is added exceeding the said upper limit, sclerosis | hardenability and the fall of adhesiveness may be caused.

  In addition to the above components (A) to (E), the composition of the present invention may further contain the following components.

(F) Release agent A release agent can be mix | blended with the thermosetting epoxy resin composition of this invention. (F) The mold release agent of a component is mix | blended in order to improve the mold release property at the time of shaping | molding.

  Mold release agents include natural waxes such as carnauba wax, synthetic waxes such as acid wax, polyethylene wax, and fatty acid ester. Generally, yellowing easily occurs under high temperature conditions or under light irradiation. In many cases, glycerin derivatives and fatty acid esters with little discoloration or carnauba wax with little discoloration over time, although having little color change, are preferred. Particularly preferred are glycerin monostearate and stearyl stearate because they are less colored initially and less discolored over time.

  (F) The compounding quantity of the mold release agent of a component is 0.05-7.0 mass parts with respect to 100 mass parts of (A) component, Especially 0.1-5.0 mass parts is preferable. If the blending amount is less than 0.05 parts by mass, sufficient releasability may not be obtained, and if it exceeds 7.0 parts by mass, a squeeze out defect or poor adhesion may occur.

(G) Coupling agent In the thermosetting epoxy resin composition of the present invention, a silane coupling agent is used to increase the bonding strength between the resin composition and the metal in order to increase the bond strength between the resin and the inorganic filler. Coupling agents such as titanate coupling agents can be blended.
Examples of such a coupling agent include epoxy functions such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. It is preferable to use a mercapto functional alkoxysilane such as a functional alkoxysilane or γ-mercaptopropyltrimethoxysilane. The amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited, but the resin discolors when left at 150 ° C. or more like an amine-based silane coupling agent. Is less preferred.

The blending amount of the component (G) is preferably 0.1 to 8.0 parts by weight, and particularly preferably 0.5 to 6.0 parts by weight with respect to 100 parts by weight of the component (A). If the amount is less than 0.1 parts by mass, the effect of bonding to the substrate is not sufficient, and if it exceeds 8.0 parts by mass, the viscosity may be extremely reduced, which may cause voids.

Other Additives Various additives can be further blended in the thermosetting epoxy resin composition of the present invention as necessary. For example, reinforcing agents such as glass fibers, additives such as silicone powder, silicone oil, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, and light stabilizers for the purpose of improving the properties of the resin do not impair the effects of the present invention. Although it can be added and blended in a range, it is preferable that the refractive index is close to the component (A) so as not to prevent light transmission.

  As a method for producing the thermosetting epoxy composition of the present invention, a prepolymer, an inorganic filler, a curing accelerator, and other additives are blended at a predetermined composition ratio, and this is sufficiently uniformly mixed by a mixer or the like. Examples thereof include a method of performing a melt mixing process using a hot roll, a kneader, an extruder, and the like, then cooling and solidifying, and pulverizing to an appropriate size to obtain a molding material for the thermosetting epoxy resin composition.

The most common molding method for the sealing material includes a transfer molding method and a compression molding method. In the transfer molding method, a transfer molding machine is used and a molding pressure of 5 to 20 N / mm ² , a molding temperature of 120 to 190 ° C., a molding time of 30 to 500 seconds, particularly a molding temperature of 150 to 185 ° C. and a molding time of 30 to 180 seconds. It is preferable. In the compression molding method, a compression molding machine is used, and the molding temperature is preferably 120 to 190 ° C., the molding time is 30 to 600 seconds, and the molding temperature is preferably 130 to 160 ° C. and the molding time is 120 to 300 seconds. Further, in any molding method, post-curing may be performed at 150 to 185 ° C. for 0.5 to 20 hours.

  The thermosetting epoxy resin composition of the present invention is heat-cured at 180 ° C. for 4 hours, 10 g of the cured product is put into 50 g of pure water, treated at 121 ° C. for 20 hours, and then insoluble matters in the liquid are removed by filtration. In the extract thus obtained, the pH of the extract is 4 or more and 7 or less, preferably 4.5 or more and 6.5 or less. If the pH is within this range, not only the heat discoloration resistance of the resin composition is improved, but also the reliability with respect to an acid-sensitive chip such as GaAs is improved. In order to make it into such a range, the method of adding the hydrotalcite compound and / or the calcined product of this hydrotalcite compound is mentioned.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

  The raw materials used in Examples and Comparative Examples are shown below.

(A-1) Epoxy resin not solid or fluid at 25 ° C. (A-1-1): Tris (2,3-epoxypropyl) isocyanurate (trade name TEPIC-S: Nissan Chemical Co., Ltd.) Made)
(A-1-2): 1,2-epoxy-4- (2 oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (A-2) acid anhydride (A-2- 1): Methylhexahydrophthalic anhydride (trade name Ricacid MH: manufactured by Shin Nippon Rika Co., Ltd.)
(A-2-2): Hexahydrophthalic anhydride (trade name: Ricacid HH: manufactured by Shin Nippon Rika Co., Ltd.)

(B) Inorganic filler (B-1): fused spherical silica (trade name: RS-8225 / 53C, average 10 μm, manufactured by Tatsumori Co., Ltd.)

(C) Curing accelerator (C-1): Phosphorus-based curing catalyst; quaternary phosphonium bromide (trade name: U-CAT5003, manufactured by San Apro Co., Ltd.)
(C-2): 2-ethyl-4-methylimidazole (trade name: 2E4MZ, manufactured by Shikoku Chemicals Co., Ltd.)

(D) Antioxidant (D-1): Phosphorous antioxidant (trade name: PEP-8, manufactured by ADEKA Corporation)
(D-2): Hindered amine antioxidant (trade name: LA-63, manufactured by ADEKA Corp.)

(E) a hydrotalcite-like compound and / or calcination of the hydrotalcite-like compound _{(E-1) :( Mg)} 6 Al 2 (CO 3) (OH) 16 · 4H 2 O fired product (trade name: (DHT-4A-2, manufactured by Kyowa Chemical Industry Co., Ltd.)
(E-2): (Mg) _4.3 Al ₂ (CO ₃ ) (OH) _12.6 · mH ₂ O (trade name: DHT-4A, manufactured by Kyowa Chemical Industry Co., Ltd.)

(F) Release agent (F-1): Stearyl stearate (trade name: SL-900A, manufactured by Riken Vitamin Co., Ltd.)

(G) Coupling agent (G-1): 3-mercaptopropyltrimethoxysilane (trade name: KBM-803, trade name manufactured by Shin-Etsu Chemical Co., Ltd.)

[Synthesis Example 1] Production of epoxy resin prepolymer (component A) Prepolymers A to D, which are components (A), are blended at the indicated ratio of raw material components shown in Table 1 below, and a predetermined amount using a gate mixer. The epoxy resin (A-1) and the acid anhydride (A-2) were reacted by heating under reaction conditions for synthesis.

[Examples 1-7, Comparative Examples 1-8]
The composition (parts by mass) shown in Tables 2 and 3 was produced with a hot two roll, cooled and pulverized to obtain a thermosetting epoxy resin composition. The following properties were measured for these compositions. The results are shown in Tables 2 and 3.

Handling property of composition The workability at the time of melt-mixing with the above-mentioned two heat rolls was evaluated according to the following criteria.
(Circle): After mixing each component uniformly, the composition which can be tableted easily was able to be obtained.
X: After mixing each component uniformly, only the composition which was difficult to tablet was obtained.

Spiral flow value A mold conforming to the EMMI standard was used under the conditions of a molding temperature of 175 ° C., a molding pressure of 6.9 N / mm ² , and a molding time of 90 seconds.

Bending strength at room temperature, flexural modulus Using a mold according to JIS-K6911: 2006 standard, molding was performed under conditions of a molding temperature of 175 ° C., a molding pressure of 6.9 N / mm ² , and a molding time of 90 seconds. Post-curing was performed at 180 ° C. for 4 hours. The post-cured test piece was measured for bending strength, bending elastic modulus and deflection at room temperature (25 ° C.).

Light transmittance, heat resistance Molding temperature of 175 ° C., molding pressure of 6.9 N / mm ² , molding time of 90 sec. Post cure was performed, and light transmittance at 740 nm was measured using X-lite 8200 manufactured by SDG Co., Ltd. Thereafter, heat treatment was performed at 180 ° C. for 500 hours, and the light transmittance at 740 nm was measured using X-lite 8200 manufactured by SDG Co., Ltd. in the same manner.

Measurement of pH Using a mold conforming to JIS-K6911: 2006, molding was performed under conditions of a molding temperature of 175 ° C., a molding pressure of 6.9 N / mm ² and a molding time of 90 seconds, and post-cured at 180 ° C. for 4 hours. . Thereafter, the molded piece was pulverized, and a pulverized product having a particle size such that it passed through 70 mesh and remained on 200 mesh was collected using a sieve. 10 g of the pulverized product was put in 50 g of pure water, treated at 121 ° C. for 20 hours, and then insoluble components in the heated liquid were removed by filtration to obtain extracted water. The pH of the obtained extract was measured.

Reliability test In advance, a silicone coating layer (KJR-9090, manufactured by Shin-Etsu Chemical Co., Ltd.) was formed on the surface of a photocoupler element (GaAs-LED) under conditions of 150 ° C. × 4 hours. Then, using the thermosetting epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 8, the photocoupler element having the silicone coating layer formed thereon was molded at a temperature of 175 ° C. and a molding pressure of 6.9 N / mm. ^2. Primary sealing was performed under conditions of a molding time of 90 seconds. Then, using a black thermosetting epoxy resin material (KMC-300, manufactured by Shin-Etsu Chemical Co., Ltd.), the outer periphery of the primary sealing resin layer was 175 ° C., a molding pressure of 6.9 N / mm ² , and a molding time of 120 seconds. A secondary sealing resin layer was formed under conditions and post-cured at 180 ° C. for 4 hours to prepare a photocoupler. Ten photocouplers thus prepared were measured under conditions of 150 ° C. × 50 mA × 5,000 hours, and the defect rate was measured.

  From Tables 2 and 3, it was confirmed that the handleability was improved by prepolymerization. In addition, the resin cured products of the examples not only have high heat resistance by containing a hydrotalcite-like compound and / or a calcined product of a hydrotalcite-like compound, but also the pH approaches to neutrality and load on the chip. It was confirmed that the material is difficult to be applied.

Claims (5)

(A) (A-1) A reaction product of an epoxy resin that is not solid or fluid at 25 ° C. and (A-2) an acid anhydride, which is an epoxy group equivalent / an acid anhydride group equivalent. Is a ratio of 0.6 to 2.0: 100 parts by mass,
(B) Inorganic filler: 80 to 1,000 parts by mass,
(C) The following formula (1):
X ⁺ Y ⁻ (1)
[In the formula (1), X ⁺ represents an aliphatic quaternary phosphonium ion, an aromatic quaternary phosphonium ion, an onium ion of 1,8-diaza-bicyclo [5.4.0] undecan-7-ene, and an imidazole derivative. Y ⁻ represents a tetrafluoroborate ion, a tetraphenylborate ion, a hexafluorophosphate ion, a bistrifluoromethylsulfonylimido ion, or a tris (trifluoromethylsulfonyl) carbonate ion. , An anion selected from trifluoromethanesulfonate ion, halogenated acetate ion, carboxylate ion and halogen ion. ]
Curing accelerator comprising an onium salt represented by: 0.05 to 5 parts by mass,
(D) One or more antioxidants selected from phenol-based, phosphorus-based and sulfur-based antioxidants: 0.01 to 10 parts by mass and (E) hydrotalcite-like compound and / or hydrotalcite Baked product of like compound: A thermosetting epoxy resin composition for primary sealing of a photocoupler, containing 1 to 10 parts by mass. The thermosetting epoxy resin composition for primary sealing of a photocoupler according to claim 1, wherein the inorganic filler of component (B) is spherical silica or glass particles. The thermosetting epoxy resin composition for primary encapsulation of a photocoupler according to claim 1 or 2, wherein the curing accelerator of component (C) is a quaternary phosphonium salt. The hydrotalcite-like compound of component (E) is represented by the following formula (2)
_{^{[M 2+ 1-x M 3+}} x (OH) 2] x + [(A n- x / n) · mH 2 O] x- (2)
^{(Wherein, M 2+} is a divalent metal ^{ion, M 3+} is a trivalent metal ^{ion, A n-is} an n-valent anion, x is the number of the range of 0 <x <1, m Represents a number from 0 to 10.)
The hydrotalcite-like compound fired product is represented by the following formula (3):
M ²⁺ _1-x M ³⁺ xO _{1 + x / 2} (3)
(X is a number in the range 0 <x <1)
The thermosetting epoxy resin composition for primary sealing of a photocoupler according to any one of claims 1 to 3, which is a compound represented by the formula:   A photocoupler primarily sealed with the thermosetting epoxy resin composition according to any one of claims 1 to 5.