JP2008120843A - Light-transmissive silicone resin, light-transmissive silicone resin composition, and optical semiconductor device - Google Patents

Abstract

A highly transparent silicone resin having high adhesive strength and heat resistance to a silver substrate and useful as a die attach material for an LED chip is provided.
The silicone resin of the present invention has an average unit formula: (R ¹ SiO _3/2 ) _a (R ² ₂ SiO _2/2 ) _b (R ³ ₃ SiO _1/2 ) _c (SiO _4/2 ) _d (XO _1/2 ) _e (wherein R ^{1 to} R ³ are monovalent hydrocarbon groups having 1 to 10 carbon atoms or an epoxy group-containing organic group, X is a hydrogen atom or an alkyl group. R ^{1 to} R ³ 0.1 to 40 mol% of the total number is an epoxy group-containing organic group, 5 mol% or more is a phenyl group, a, e are positive numbers, b, c, d are 0 or positive numbers, b / a is 0 -10, c / a is 0 to 5, d / (a + b + c + d) is 0 to 0.5, and e / (a + b + c + d) is 0.01 to 1.) Epoxy which is liquid at room temperature and produces a transparent cured product upon heating. It is a group-containing silicone resin.
[Selection figure] None

Description

  The present invention relates to a light-transmitting silicone resin and a light-transmitting silicone resin composition used for bonding or sealing a semiconductor (photo-semiconductor) element that functions by transmitting and receiving optical signals, such as LEDs, CCDs, and photocouplers. And an optical semiconductor device bonded or sealed with such a resin or resin composition.

  Conventionally, a highly transparent epoxy resin has been used as a material for bonding or sealing optical semiconductor elements such as LEDs, CCDs, and photocouplers. In particular, as a die attach material for adhering the LED chip on the substrate or the cup, an epoxy resin is frequently used because of its high adhesiveness. However, in recent years, deterioration and discoloration of the epoxy resin are becoming a problem as the heat generation amount of the LED increases. On the other hand, the use of addition-reactive silicone rubber as a die attach material or sealing material for optical semiconductors is also considered, but there is a problem that the adhesive strength is low.

  Conventionally, polyorganosiloxanes containing epoxy groups and silanol groups have been used as light transmissive resin materials that have high adhesive strength and heat resistance and are useful as die attach materials and sealing materials for optical semiconductors such as LEDs. There is known an epoxy-modified silicone resin composition comprising a silicone resin having a viscosity and a curing catalyst. (For example, see Patent Document 1)

In addition, an epoxy resin composition comprising an epoxy resin, (a) a silicone resin having an epoxy group or amino group, and (b) a hydroxyl group or a hydrolyzable group, a curing agent and an inorganic filler (for example, see Patent Document 2) A curable resin composition (see, for example, Patent Document 3) comprising an epoxy resin, a silicone resin, an epoxy group-containing polyorganosiloxane that is a block copolymer, an inorganic filler, and a curing catalyst is known. Furthermore, an epoxy resin composition comprising a compound having two or more epoxies in one molecule, an acid anhydride curing agent, a specific surface-treated filler (for example, see Patent Document 4), and the like are also known. .
JP-A-5-287077 Japanese Patent Publication No. 62-27095 Japanese Patent Laid-Open No. 56-145942 JP-A-4-236217

  However, the epoxy-modified silicone resin composition described in Patent Document 1 has a problem that transparency is not sufficient and adhesion to silver as a substrate is insufficient. In addition, the curable resin compositions described in Patent Document 2 and Patent Document 3 also have insufficient transparency. Furthermore, the epoxy resin composition described in Patent Document 4 has a problem in that it has transparency but is insufficient in heat resistance and has a large discoloration during heat generation.

  The present invention has been made to solve these problems, and has high adhesive strength and heat resistance to metal substrates such as silver, and has high transparency useful as a die attach material for LED chips. An object of the present invention is to provide an epoxy group-containing silicone resin and a composition thereof.

The light transmissive silicone resin of the present invention has an average unit formula:
(R ¹ SiO _3/2 ) _a (R ² ₂ SiO _2/2 ) _b (R ³ ₃ SiO _1/2 ) _c (SiO _4/2 ) _d (XO _1/2 ) _e (wherein R ¹ , R ² and R ³ are the same or different monovalent hydrocarbon group or epoxy group-containing organic group having 1 to 10 carbon atoms, and X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, provided that ¹ to 40 mol% is an epoxy group-containing organic group, 5 mol% or more is a phenyl group, and a and e are positive numbers, based on the total number of R ^{1 to} R ³ in the molecule. b, c and d are all 0 or a positive number, and b / a is a number from 0 to 10, c / a is a number from 0 to 5, and d / (a + b + c + d) is 0 to 0. E / (a + b + c + d) is a number of 0.01 to 1), and is liquid at room temperature and transparent by heating. Wherein the causing Do cured product.

  The light transmissive silicone resin composition of the present invention contains (A) the light transmissive silicone resin of the present invention and (B) a curing agent having two or more groups that react with an epoxy group in one molecule. And a transparent cured product is produced by heating.

  The optical semiconductor device of the present invention is characterized in that an optical semiconductor element is bonded onto a substrate with the above-described light-transmitting silicone resin or light-transmitting silicone resin composition of the present invention.

  The optical semiconductor device of the present invention is characterized in that an optical semiconductor element is sealed with the above-described light transmissive silicone resin or light transmissive silicone resin composition of the present invention.

  The light transmissive silicone resin of the present invention is cured by heating to produce a cured product having excellent transparency and high adhesive strength and heat resistance. In addition, the light-transmitting silicone resin composition of the present invention obtained by mixing such a light-transmitting silicone resin with a curing agent such as an acid anhydride is cured by heating, has good transparency and high adhesive strength. A cured product having heat resistance is produced. Therefore, the light transmissive silicone resin and the composition thereof of the present invention are useful as materials for bonding and sealing optical semiconductor elements such as LEDs, CCDs, and photocouplers, and are particularly suitable as LED die attach. ing.

  Hereinafter, embodiments of the present invention will be described. First, an embodiment of the silicone resin that is the component (A) of the present invention will be described.

The component (A) has a unit (T unit) represented by the formula: R ¹ SiO _3/2 , a unit (D unit) represented by the formula: R ² ₂ SiO _2/2 , and a formula: R ³ ₃ SiO. A silicone resin that is liquid at room temperature and has at least one unit selected from a unit (M unit) represented by _1/2 and a unit (Q unit) represented by SiO _4/2.
(R ¹ SiO _3/2 ) _a (R ² ₂ SiO _2/2 ) _b (R ³ ₃ SiO _1/2 ) _c (SiO _4/2 ) _d (XO _1/2 ) _e

In the above formula, R ¹ , R ² and R ³ are the same or different monovalent hydrocarbon group or epoxy group-containing organic group (hydrocarbon group) having 1 to 10 carbon atoms.

  Examples of monovalent hydrocarbon groups include methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups and other alkyl groups; vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, etc. Alkenyl group; aryl group such as phenyl group, tolyl group and xylyl group; aralkyl group such as benzyl group and phenethyl group; chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, nonafluorobutyl Examples include substituted alkyl groups such as an ethyl group. Among them, a monovalent hydrocarbon group having 1 to 8 carbon atoms is preferable, and a methyl group or a phenyl group is particularly preferable. In addition, the epoxy group-containing organic group includes 2,3-epoxypropyl group, 3,4-epoxybutyl group, 4,5-epoxypentyl group and the like; 2-glycidoxyethyl group, 3-glycol Glycidoxyalkyl groups such as a sidoxypropyl group and 4-glycidoxybutyl group; β- (or 2-) (3,4-epoxycyclohexyl) ethyl group, γ- (or 3-) (3,4- Examples are epoxycyclohexylalkyl groups such as (epoxycyclohexyl) propyl group.

However, 1 to 40 mol% based on the total number of ^R 1 to R ³ in the molecule are the epoxy group-containing organic group. When the content of the epoxy group-containing organic group is less than the lower limit of the above range, curability becomes insufficient. On the other hand, when the upper limit of the above range is exceeded, there is a problem that the viscosity is difficult to adjust, which is not preferable. Further, since it is superior in that it is possible to increase the refractive index, it is preferable 5 to 40 mol% based on the total number of R ¹ to R ³ is a phenyl group. In particular, 5 to 40 mol% of R ¹ is preferably a phenyl group.

  X in the above formula is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. That is, the silicone resin has a hydroxyl group bonded to a silicon atom or an alkoxy group that is a hydrolyzable group.

  Further, a and e in the above formula are positive numbers, and b, c and d are all 0 or positive numbers. B / a is a number from 0 to 10, c / a is a number from 0 to 5, d / (a + b + c + d) is a number from 0 to 0.5, and e / (a + b + c + d) is 0. It is a number from 01 to 1. When the values of a to e are out of the above range, the curability is lowered, which is not preferable.

  The viscosity of the component (A) at 25 ° C. is not particularly limited, but is preferably in the range of 1,000 to 5,000,000 mPa · s, and particularly preferably in the range of 2,000 to 2,000,000 mPa · s. s. The average molecular weight of the component (A) is not particularly limited, but the weight average molecular weight is preferably in the range of 500 to 100,000, and particularly preferably in the range of 800 to 30,000.

  The method for preparing the silicone resin as the component (A) is not limited, but for example, the following method can be adopted.

That is, a unit represented by (A1) (1) formula: R ⁴ SiO _3/2 (wherein R ⁴ is a monovalent hydrocarbon group), (2) formula: R ⁵ ₂ SiO _2/2 (Wherein R ⁵ are the same or different monovalent hydrocarbon groups), (3) Formula: R ⁶ ₃ SiO _1/2 (wherein R ⁶ is the same or different 1 And a mixture of one or more of silanes or siloxanes having at least one selected from the units represented by formula (4): SiO _4/2 (A2) General formula: R ⁷ R ⁸ _f Si (OR ⁹ ) _(3-f) (wherein R ⁷ is an epoxy group-containing organic group, R ⁸ is a monovalent hydrocarbon group, R ⁹ .f alkyl groups is 0, 1 or 2. epoxy group represented by) containing alkoxysilane or its The partial hydrolyzate, it is preferable to adopt a method of reacting in the presence of a basic catalyst.

R ⁴ , R ⁵ and R ⁶ in the above formula are the same or different monovalent hydrocarbon groups, and the same monovalent hydrocarbon groups as R ¹ , R ² or R ³ are exemplified. Preferably more than 10 mol% of R ⁴ is a phenyl group, and particularly preferably more than 30 mol% of R ⁴ is a phenyl group.

  Examples of the silane or siloxane as the component (A1) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, 3,3,3- Trifluoropropyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, methylphenyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, dimethoxydi Examples thereof include ethoxysilane and hydrolytic condensates thereof.

The component (A2) is a component for introducing an epoxy group-containing organic group, and is represented by the general formula: R ⁷ R ⁸ _f Si (OR ⁹ ) _(3-f) . R ⁷ in the formula is an epoxy group-containing organic group, and examples thereof are the same as the epoxy group-containing organic group in R ¹ , R ² or R ³ . R ⁸ is a monovalent hydrocarbon group, and the same monovalent hydrocarbon group as R ¹ , R ² or R ³ is exemplified. R ⁹ is an alkyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. F in the formula is 0, 1 or 2, and preferably 0.

  Examples of the epoxy group-containing alkoxysilane (A2) include 3-glycidoxypropyl (methyl) dimethoxysilane, 3-glycidoxypropyl (methyl) diethoxysilane, and 3-glycidoxypropyl (methyl) dibutoxy. Silane, 2- (3,4-epoxycyclohexyl) ethyl (methyl) dimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl (phenyl) diethoxysilane, 2,3-epoxypropyl (methyl) dimethoxysilane, 2 , 3-epoxypropyl (phenyl) dimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltributoxysilane, 2- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl Examples include rutriethoxysilane, 2,3-epoxypropyltrimethoxysilane, and 2,3-epoxypropyltriethoxysilane.

  In the above production method, the components (A1) and (A2) are reacted in the presence of a basic catalyst. The basic catalyst is a catalyst for co-hydrolyzing the (A1) component and the (A2) component to cause a condensation reaction. For example, alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, cesium hydroxide, etc. An alkali metal alkoxide such as sodium-t-butoxide, potassium-t-butoxide and cesium-t-butoxide; and an alkali metal silanol compound such as a sodium silanolate compound, a potassium silanolate compound and a cesium silanolate compound. In order to co-hydrolyze and condense the components (A1) and (A2), water may be added as necessary. Further, after reacting the component (A1) and the component (A2), the solid content concentration in the reaction system may be adjusted with an organic solvent as necessary, and further reacted.

  Furthermore, by the equilibration reaction with a basic catalyst, siloxane bond cleavage and recombination occur randomly, and as a result, the resulting epoxy group-containing silicone resin may be in an equilibrium state. If the reaction temperature is too low, the equilibration reaction will not proceed sufficiently, and if the reaction temperature is too high, the silicon-bonded organic group will be thermally decomposed, so the reaction temperature of the equilibration reaction should be 80 ° C to 200 ° C. It is preferable that it is 100 to 150 degreeC especially. Further, by selecting an organic solvent having a boiling point of 80 to 200 ° C., the equilibration reaction can be easily performed at the reflux temperature. The equilibration reaction can be stopped by neutralizing the basic catalyst. For neutralization, it is preferable to add a weak acid such as carbon dioxide or carboxylic acid. The salt produced by neutralization can be easily removed by filtration or washing with water.

  Next, the light transmissive silicone resin composition of the embodiment will be described. The light-transmitting silicone resin composition of the embodiment contains the light-transmitting silicone resin as the component (A) and (B) the curing agent, and the curing agent as the component (B) is 1 A compound having two or more groups that react with an epoxy group in the molecule is used.

  As this (B) curing agent, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, dodecyl succinic anhydride, methyl nadic anhydride, Acid anhydrides such as benzophenone tetracarboxylic anhydride and butane tetracarboxylic anhydride, ethylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-aminoethylpiperazine, bis (4-amino-3-methylcyclohexyl) methane, metaxyl Amino compounds such as lenamine, menthanediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-5,5) undecane, epoxy resin-diethylenetriamine adduct, amine-ethylene oxide adac , Mention may be made of modified aliphatic polyamines such as cyanoethylated polyamines, phenols, bisphenol A, bisphenol F, tetrabromobisphenol A, phenol compounds such as cresol, and xylene resin.

  In the embodiment of the present invention, it is particularly preferable to use an acid anhydride having compatibility with the component (A). The compounding quantity of an acid anhydride hardening | curing agent can be made into a normal quantity. (A) It is preferable to set it as 1-100 weight part with respect to 100 weight part of component. Alternatively, the number of moles of acid anhydride is preferably in the range of 0.2 to 1.5 times the number of moles of the epoxy group of component (A). Particularly preferably, the number of moles of acid anhydride is in the range of 0.4 to 1.0 times.

  The light transmissive silicone resin composition of the embodiment of the present invention contains (C) an organic compound having two or more epoxy groups in one molecule, together with such a component (A) and component (B). be able to.

  (C) As a compound which has 2 or more of epoxy groups in 1 molecule which is a component, conventionally well-known various epoxy resins can be used regardless of liquid state and solid state. Specific examples include epoxy resins synthesized from various novolak resins such as epichlorohydrin and bisphenol, alicyclic epoxy resins, or epoxy resins introduced with halogen atoms such as chlorine and bromine atoms. One kind can be used alone or two or more kinds can be used in combination. Among these, it is particularly preferable to use a bisphenol type epoxy resin with little coloring. When the component (C) is added, the number of moles of acid anhydride is in the range of 0.2 to 1.5 times the total number of moles of the epoxy groups of the components (A) and (C). The number of moles of acid anhydride is preferably in the range of 0.4 to 1.0 times.

  A curing accelerator can be added to the silicone resin composition of the embodiment of the present invention as necessary. Examples of the curing accelerator include phosphorus such as triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylborate, tetraphenylphosphine / tetraphenylborate. System compounds; tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 1,8-diazabicyclo [5.4.0] undecene-7; 2-methylimidazole, 2-phenylimidazole, 2 -Imidazole compounds such as phenyl-4-methylimidazole.

  Moreover, you may mix | blend a small amount of additives, for example, pigments and dyes, such as a plasticizer, a peeling agent, a flame retardant, antioxidant, a ultraviolet absorber, titanium dioxide, carbon black, or iron oxide. Furthermore, fumed silica, silica airgel, silica gel, and reinforcing silica fillers treated with organosilanes, organosiloxanes or organosilazanes, asbestos, crushed fused quartz, aluminum oxide, aluminum oxalate, oxalic acid Zirconium, magnesium oxide, zinc oxide, talc, diatomaceous earth, mica, calcium carbonate, clay, zirconia, glass, sand, graphite, barium sulfate, zinc sulfate, aluminum powder, sawdust, cork, fluorocarbon polymer powder, silicone rubber powder, You may mix | blend fillers, such as silicone resin powder. Furthermore, an organic solvent may be blended as necessary.

  The silicone resin and silicone resin composition of the embodiment of the present invention are liquid at room temperature and have good light transmission (transparency). Moreover, it is excellent in sclerosis | hardenability and it hardens | cures by heating and gives hardened | cured material with favorable light transmittance. The obtained cured product has good mechanical strength, moisture resistance, heat resistance, weather resistance, and the like, and also has high adhesion to various base materials including silver. Therefore, the silicone resin and the silicone resin composition can be suitably used for bonding or sealing an optical semiconductor such as an LED, CCD, or photocoupler.

Furthermore, the silicone resin of the embodiment has a refractive index at 25 ° C. (for example, measured by an Abbe refractometer) of 1.42 to 1.54, and the refractive index of the curing agent or filler (for example, hexahydro, which is a curing agent). The refractive index n of phthalic anhydride at 25 ° C. is 1.48, and the refractive index n of SiO ₂ as a filler at 25 ° C. is 1.458. Even when blended, light scattering does not occur at the interface, and a highly transparent cured product can be obtained. Therefore, it is particularly suitable for sealing an optical semiconductor.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example.

Example 1
A four-necked flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 221 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 312 g of phenyltrimethoxysilane, 243 g of dimethyldimethoxysilane and 138 g of methyltrimethoxysilane. Was added together with 225 g of toluene and mixed uniformly, and then a mixed solution of 60 g of water and 1.5 g of 6N-NaOH aqueous solution was added dropwise. Further, 64 g of water was added and mixed, and then heated and stirred at the reflux temperature of methanol for 1 hour.

  Thereafter, 304 g of toluene was added, the reflux tube was switched to a distillation system, and then heated to 100 ° C. to distill off methanol. Next, the mixture was cooled to room temperature, 1 g of acetic acid was added and mixed, the impurities were filtered, and then the filtrate was heated under reduced pressure to distill off toluene. In this way, 594 g of a transparent liquid product (S1) was obtained.

  The obtained product had an epoxy equivalent of 636, a weight average molecular weight of 10,000, and a viscosity at 25 ° C. (measured with a rotational viscometer) of 1000 Pa · s. Further, a refractive index of 25 ° C. was measured using an Abbe refractometer No. It was 1.49 when measured by 25368.

When this product was analyzed by ²⁹ Si-nuclear magnetic resonance spectrum analysis, it was confirmed that it was a polyorganosiloxane (epoxy group-containing silicone resin) (S1) having the following average unit formula.
Average unit formula: (EpSiO _3/2 ) ₁₆ (PhSiO _3/2 ) ₂₉ (MeSiO _3/2 ) ₁₈ (Me ₂ SiO _2/2 ) ₃₇ (XO _1/2 ) ₁₆
(In the formula, Ep: 2- (3,4-epoxycyclohexyl) ethyl group, Ph: phenyl group, Me: methyl group, X: hydrogen atom or methyl group.)

  Subsequently, when this epoxy group-containing silicone resin (S1) was heated at 180 ° C. for 12 hours, a transparent cured product was obtained.

Example 2
88 g of the silicone resin (S1) obtained in Example 1 was mixed with 8.4 g of 4-methylhexahydrophthalic anhydride and 3.6 g of hexahydrophthalic anhydride as a curing agent (refractive index of 1.48 at 25 ° C. ) Was added and mixed, and 0.1 g of U-CAT5003 (manufactured by San Apro), which is a curing accelerator, was further added and mixed. Thereafter, vacuum degassing was performed to obtain a transparent liquid epoxy group-containing silicone resin composition. It was 55 Pa.s when the viscosity (25 degreeC) of this liquid composition was measured with the rotational viscometer. Further, the refractive index of this resin composition at 25 ° C. was 1.49.

  Next, the epoxy group-containing silicone resin composition thus obtained was placed in a mold surface-coated with Teflon (registered trademark) and heated at 120 ° C. for 1 hour and then at 150 ° C. for 1 hour to obtain a transparent cured product. was gotten. The cured product had a light transmittance of 90% and a hardness (measured with a Shore D hardness meter) of 65. In addition, the measurement of the light transmittance measured the transmittance | permeability of the light of wavelength 550nm with the ultraviolet visible spectrophotometer about the hardened | cured material of thickness 1.5mm.

  Moreover, the die shear strength of the obtained silicone resin composition was measured based on US STD-883. That is, after applying the epoxy group-containing silicone resin composition obtained in Example 2 to one side of a 4 mm square silicon die, this surface was brought into contact with a silver plate, and then at 120 ° C. for 1 hour and then at 150 ° C. for 1 hour. Bonded by heating. The die shear strength of this adhesion test piece was measured with a Series 4000 Bondtester manufactured by Dage, and found to be 35 kgf.

Example 3
To 65 g of the silicone resin (S) obtained in Example 1, 19.2 g of (3 ′, 4′-epoxycyclohexane) methyl-3,4-epoxycyclohexanecarboxylate (refractive index of 1.50 at 25 ° C.) As a curing agent, a mixture of 8.4 g of 4-methylhexahydrophthalic anhydride and 3.6 g of hexahydrophthalic anhydride (refractive index of 1.48 at 25 ° C.) was added and mixed, and further, U— which is a curing accelerator. CAT5003 (manufactured by San Apro) 0.1 g was added and mixed. Thereafter, vacuum degassing was performed to obtain a transparent liquid epoxy group-containing silicone resin composition. It was 9 Pa.s when the viscosity (25 degreeC) of this liquid composition was measured with the rotational viscometer. Further, the refractive index of this resin composition at 25 ° C. was 1.49.

  Next, the epoxy group-containing silicone resin composition thus obtained was placed in a mold surface-coated with Teflon (registered trademark) and heated at 120 ° C. for 1 hour and then at 150 ° C. for 1 hour to obtain a transparent cured product. was gotten. The light transmittance of this cured product measured in the same manner as in Example 2 was 89%, and the hardness (measured with a Shore D hardness meter) was 75.

  Moreover, the die shear strength of the obtained silicone resin composition was measured based on US STD-883. That is, after the epoxy group-containing silicone resin composition obtained in Example 3 was applied to one side of a 4 mm square silicon die, this surface was brought into contact with a silver plate, and then at 120 ° C. for 1 hour and then at 150 ° C. for 1 hour. Heated. It was 31 kgf when the die shear strength of this adhesion test piece was measured by Series4000Bondtester made from Dage.

Example 4
A four-necked flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 428 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 190 g of phenyltrimethoxysilane, 324 g of dimethyldimethoxysilane and 82 g of methyltrimethoxysilane. Was added together with 450 g of toluene and mixed uniformly, and then a mixed solution of 60 g of water and 1.7 g of 6N-NaOH aqueous solution was dropped and mixed. Further, 64 g of water was added and mixed, and then heated and stirred at the reflux temperature of methanol for 1 hour.

  Thereafter, 600 g of toluene was added, the reflux tube was switched to a distillation system, and then heated to 100 ° C. to distill off methanol. Next, the mixture was cooled to room temperature, and 1.8 g of acetic acid was added and mixed. After impurities were filtered, toluene was distilled off by heating the filtrate under reduced pressure. In this way, 670 g of a transparent liquid product (S2) was obtained.

  The obtained product had an epoxy equivalent of 400, a weight average molecular weight of 2000, and a viscosity at 25 ° C. of 10 Pa · s. Further, a refractive index of 25 ° C. was measured using an Abbe refractometer No. It was 1.48 when measured by 25368.

And when this product was analyzed by ²⁹ Si-nuclear magnetic resonance spectrum analysis, it was confirmed that it was a polyorganosiloxane (epoxy group-containing silicone resin) (S2) having the following average unit formula.
Average unit formula: (EpSiO _3/2 ) ₂₉ (PhSiO _3/2 ) ₁₆ (MeSiO _3/2 ) ₄₅ (Me ₂ SiO _2/2 ) ₁₀ (XO _1/2 ) ₂₆
(In the formula, Ep: 2- (3,4-epoxycyclohexyl) ethyl group, Ph: phenyl group, Me: methyl group, X: hydrogen atom or methyl group.)

  To a silicone resin (S2) 83 g, a mixture of 11.9 g of 4-methylhexahydrophthalic anhydride and 5.1 g of hexahydrophthalic anhydride (refractive index at 25 ° C. of 1.48) was added and mixed as a curing agent, Furthermore, 0.1 g of U-CAT5003 (manufactured by Sun Apro) which is a curing accelerator was added and mixed. Thereafter, vacuum degassing was performed to obtain a transparent liquid epoxy group-containing silicone resin composition. It was 2 Pa * s when the viscosity (25 degreeC) of this liquid composition was measured with the rotational viscometer. Further, the refractive index of this resin composition at 25 ° C. was 1.48.

  Next, the epoxy group-containing silicone resin composition thus obtained was placed in a mold surface-coated with Teflon (registered trademark) and heated at 120 ° C. for 1 hour and then at 150 ° C. for 2 hours to obtain a transparent cured product. was gotten. The light transmittance of this cured product was 91%, and the hardness (measured with a Shore D hardness meter) was 70.

  The silicone resin and silicone resin composition obtained by the present invention are liquid at room temperature and highly transparent, and have excellent curability, are cured by heating and are transparent, and have good mechanical strength, moisture resistance, heat resistance, and weather resistance. Provided is a cured product having high adhesion to various base materials including silver. Therefore, it can be suitably used for bonding or sealing optical semiconductors such as LEDs, CCDs, and photocouplers.

Claims (7)

Average unit formula:
(R ¹ SiO _3/2 ) _a (R ² ₂ SiO _2/2 ) _b (R ³ ₃ SiO _1/2 ) _c (SiO _4/2 ) _d (XO _1/2 ) _e (wherein R ¹ , R ² and R ³ are the same or different monovalent hydrocarbon group or epoxy group-containing organic group having 1 to 10 carbon atoms, and X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, provided that ¹ to 40 mol% is an epoxy group-containing organic group, 5 mol% or more is a phenyl group, and a and e are positive numbers, based on the total number of R ^{1 to} R ³ in the molecule. b, c and d are all 0 or a positive number, and b / a is a number from 0 to 10, c / a is a number from 0 to 5, and d / (a + b + c + d) is 0 to 0. E / (a + b + c + d) is a number of 0.01 to 1), and is liquid at room temperature and transparent by heating. Light transmitting silicone resin, characterized in that to produce a Do cured product.   The light-transmitting silicone resin according to claim 1, wherein the refractive index at 25 ° C is 1.42 to 1.54.   A cured product that contains (A) a light-transmitting silicone resin according to claim 1 or 2 and (B) a curing agent having two or more groups that react with an epoxy group in one molecule, and is transparent by heating. A light-transmissive silicone resin composition characterized by   4. The light transmissive silicone resin composition according to claim 3, wherein the (B) curing agent is an acid anhydride compatible with the component (A).   5. The light-transmitting silicone resin composition according to claim 3, comprising (C) an organic compound having two or more epoxy groups in one molecule together with the component (A) and the component (B). object.   6. An optical semiconductor device, wherein the optical semiconductor element is bonded onto a substrate with the light transmissive silicone resin or the light transmissive silicone resin composition according to any one of claims 1 to 5.   An optical semiconductor device, wherein the optical semiconductor element is sealed with the light-transmitting silicone resin or the light-transmitting silicone resin composition according to any one of claims 1 to 5.