JP2007270004A - Curable silicone resin composition, translucent sealing material and light emitting device using the same - Google Patents

Abstract

The present invention relates to a curable silicone resin composition that can be sealed at a temperature lower than 300 ° C. and can be used as a light-transmitting sealing material excellent in light transmittance, heat resistance, and light resistance in a wavelength region from ultraviolet light to visible light. Providing things.
A curable methyl phenyl silicone resin in which the proportion of a linear methyl phenyl silicone resin having one or both ends of a silanol group is 60 to 100% by mass, and a metal alkoxide, Curable silicone resin in which the ratio of metal alkoxides to the total of methylphenyl silicone resin and metal alkoxides (provided that the ratio of metal alkoxides is a ratio converted to metal oxide) is 1 to 30% by mass. A curable silicone resin composition, wherein the cured product is a translucent cured product having a refractive index (measured by 633 nm light) of 1.48 or more.
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Description

The present invention relates to a curable silicone resin composition whose cured product has excellent properties as a translucent sealing material. In this specification, “translucent sealing” means sealing having both a function of transmitting light and a sealing function, and “translucent sealing material” has such a function. It means a sealing material. In the present specification, when “translucent” or “translucent” is referred to, it means that light in the wavelength region of visible light (400 to 800 nm) is transmitted from near-ultraviolet light, preferably the wavelength region. Light transmittance (at a thickness of 100 μm) is 80% or more, more preferably 90% or more.
The present invention also relates to a translucent sealing material using the curable silicone resin composition.
The present invention also relates to a light-emitting element that is translucently sealed using the curable silicone resin composition.

  Currently, lighting equipment using a white light emitting diode (hereinafter referred to as “LED”) as a light emitting element is being put into practical use. Advantages when using white LEDs as illumination include 1) less power consumption and lower running costs compared to incandescent and fluorescent lamps, 2) long lifespan, saving replacement, and 3) miniaturization. 4) Do not use harmful substances such as mercury in fluorescent lamps.

  A general white LED has a structure in which the LED is transparently sealed with a transparent resin. For example, in a typical one-chip white LED, a blue LED, for example, a blue LED having an emission layer of InGaN in which In is added to GaN, a phosphor that emits yellow light by blue light emitted from the LED, for example, It is light-transparent sealed with a transparent resin containing a YAG phosphor. As a transparent resin used for translucent sealing, an epoxy resin has been conventionally used. When current is passed through the blue LED, blue light (wavelength 450 to 460 nm) is emitted from the LED. Next, the YAG phosphor is excited by part of the blue light, and yellow light is emitted from the phosphor. Since blue light and yellow light are in a complementary color relationship, when they are mixed, they are recognized as white light by human eyes.

  However, epoxy resins are inferior in heat resistance and light resistance (especially UV resistance). Therefore, when used for a long period of time, the epoxy resin is thermally deteriorated or light deteriorates, and moisture enters from the sealed portion. Thus, there is a problem that the operation of the LED is hindered or the resin is discolored by the ultraviolet rays emitted from the LED, and the light transmittance of the light-transmitting sealed portion is lowered.

  Further, the LED can be used at a higher ambient temperature and a larger input as the heat resistance from the mounting substrate to the light emitting portion is smaller and the heat resistant temperature is higher. Therefore, thermal resistance and heat resistance are key points for increasing the output of the LED. However, since the epoxy resin is inferior in heat resistance, there is a problem that it is not suitable for use at high output. For example, an epoxy resin turns yellow at a temperature of 130 ° C. or higher.

  In order to solve the above problems, it has been disclosed to use a fluorinated cured product for light-transmitting sealing of a light emitting element (see Patent Document 1). Fluorine-containing cured products are superior in transparency, light resistance and heat resistance compared to epoxy resins, but are inferior in adhesion to the object to be sealed, so that there is a problem that they are easily peeled off from the object to be sealed. is there. In addition, the material of the LED chip, specifically the material of the light emitting layer of the LED chip, has a high refractive index, specifically the refractive index of light in the visible light region, which is as high as 2.5 to 3.0. Since the cured product has a low refractive index of light in the same wavelength region, extraction efficiency of light in the same wavelength region is not always sufficient.

On the other hand, LED sealed with the glass produced by the sol-gel method is proposed conventionally (refer patent document 2). According to this LED, it is possible to reduce the hygroscopicity through the sealing material and the light transmission deterioration due to the discoloration of the sealing material, and it is also possible to improve the heat resistance.
However, the sol-gel glass tends to have pores, and if moisture enters the pores, there is a problem that the operation of the LED is hindered. In general, glass is inferior in adhesiveness to a substrate or a wiring metal compared to a resin, so that there is a problem that moisture enters from the interface between the sealing glass and the substrate or the wiring metal.

  In addition, it has also been proposed that the low melting point glass is heated and melted to transparently seal the LED (see Patent Document 3). However, generally, when the low-melting glass is heated and melted, it is necessary to heat the glass to a temperature of 400 to 700 ° C. Therefore, there is a possibility that the phosphor used in the LED is subjected to thermal deterioration.

International Publication No. 2005-085303 Pamphlet Japanese Patent Laid-Open No. 2002-203989 JP 2004-356506 A

In order to solve the above-described problems in the prior art, the present invention can be sealed at a temperature lower than 300 ° C., and has excellent light transmittance, heat resistance, and light resistance in a wavelength region from ultraviolet light to visible light. It aims at providing the curable silicone resin composition which can be used as a light-sealing sealing material, and the translucent sealing material using this curable silicone resin composition.
Another object of the present invention is to provide a light-emitting element that is light-transparent sealed using the curable silicone resin composition.

In order to achieve the above object, the present invention provides a curable methylphenyl silicone resin in which the proportion of a linear methylphenyl silicone resin having one or both ends of a silanol group is 60 to 100% by mass;
Metal alkoxides, and
Curing in which the ratio of metal alkoxides to the total of the curable methyl phenyl silicone resin and the metal alkoxides (however, the ratio of metal alkoxides is a ratio converted to metal oxide) is 1 to 30% by mass. A silicone resin composition comprising:
Provided is a curable silicone resin composition in which the cured product becomes a translucent cured product having a refractive index (measured by 633 nm light) of 1.48 or more.

In the curable silicone resin composition of the present invention, the curable methylphenylsilicone resin contains a trifunctional silicon unit or a polyfunctional curable methylphenylsilicone resin containing a trifunctional silicon unit and a bifunctional silicon unit. Including more than 40% by weight
It is preferable that the molar ratio of the trifunctional silicon unit to the total of the trifunctional silicon unit and the bifunctional silicon unit in the polyfunctional curable methylphenyl silicone resin is 0.4 to 1.0.

  In the curable silicone resin composition of the present invention, the molar ratio of phenyl groups to methyl groups in the polyfunctional curable methylphenyl silicone resin is preferably 0.4 to 1.2.

  In the curable silicone resin composition of the present invention, the metal alkoxide is preferably at least one selected from the group consisting of titanium alkoxides, zirconium alkoxides and oligomers thereof.

  The curable silicone resin composition of the present invention may further contain a fluorescent material.

  Moreover, this invention provides the translucent sealing material which consists of a curable silicone resin composition of this invention.

  Moreover, this invention provides the light emitting element light-transparent-sealed with the hardened | cured material of the curable silicone resin composition of this invention.

  The curable silicone resin composition of the present invention, when used as a translucent sealing material, is far more transparent than a conventional low melting glass heated and melted at a temperature of 400 to 700 ° C. Can be transparently sealed at a low temperature (130 ° C. to 300 ° C.). Thereby, when LED is light-transparent-sealed, a possibility that the fluorescent substance in LED may receive thermal deterioration is reduced.

Further, the cured product of the curable silicone resin composition of the present invention is a translucent cured product having excellent light transmittance in the wavelength region from near ultraviolet light to visible light. Therefore, when the curable silicone resin composition of the present invention is used as a translucent sealing material, the sealing portion is excellent in light transmittance in the above wavelength region.
The cured product of the curable silicone resin composition of the present invention is excellent in light resistance, particularly ultraviolet resistance. Therefore, when the curable silicone resin composition of the present invention is used as a translucent sealing material, the sealing portion is excellent in light resistance, particularly ultraviolet resistance.

  In addition, the cured product of the curable silicone resin composition of the present invention has high adhesive strength, excellent adhesive processability, high mechanical heat resistance over a long period of time, good gas leak resistance, high airtightness retention, and high heat resistance. It has many characteristics such as good dimensional stability. When the curable silicone resin composition of the present invention is used as a light-transmitting encapsulant, the encapsulated portion has both of these characteristics.

  A light-emitting element that is translucently sealed using a cured product of the curable silicone resin composition of the present invention has excellent long-term reliability. In other words, even when used for a long period of time, the sealing part is thermally deteriorated or light deteriorates, moisture enters from the sealed part and the operation of the LED is inhibited, or the resin is discolored by ultraviolet rays emitted from the LED, There is no possibility that the light transmittance of the light-transmitting sealing portion is lowered.

  A white LED can be produced by translucently sealing a blue LED or a near-ultraviolet LED using a curable silicone resin composition of the present invention containing a desired fluorescent substance.

The curable silicone resin composition of the present invention contains a curable methylphenyl silicone resin and a metal alkoxide, and its cured product (hereinafter referred to as “resin cured product”) has a refractive index (by 633 nm light). Measurement value) 1.48 or more translucent cured product.
A light-transmitting cured product having a refractive index (measured by 633 nm light) of 1.48 or more is excellent in light transmittance (at a thickness of 100 μm) in a wavelength range from 400 nm to 800 nm from near ultraviolet light to visible light, Specifically, the light transmittance in the wavelength region is 80% or more. For this reason, it is suitable as a translucent sealing material for light emitting elements such as LEDs. The light transmittance of the resin cured product is more preferably 90% or more.

Each component of the curable silicone resin composition of the present invention will be described in detail below.
The curable silicone resin composition of the present invention is a linear methylphenyl silicone resin having a silanol group at one end or both ends as a curable methylphenyl silicone resin (hereinafter referred to as “linear methylphenyl silicone resin”). Containing.
The linear methylphenyl silicone resin has less curing shrinkage during heat curing than the polyfunctional curable methylphenyl silicone resin described below. For this reason, there is a low possibility that bubbles remain in the cured resin or cracks are generated.
Further, since the resin has a linear structure, the cured resin has excellent flexibility, which also contributes to preventing cracks from occurring in the cured resin.
The linear methylphenyl silicone resin is excellent in heat resistance and can be uniformly dispersed in the curable silicone resin composition.

The silanol groups at one or both ends condense with the metal alkoxides and polyfunctional curable methylphenyl silicone resin described later when the curable silicone resin composition is heated and cured. Thereby, when the curable silicone resin composition of this invention is used as a translucent sealing material, it is prevented that a linear methylphenyl silicone resin bleeds out from a sealing part.
The linear methylphenyl silicone resin may be either one having a silanol group at one end or one having a silanol group at both ends. Further, the curable silicone resin composition of the present invention may contain both a linear methylphenyl silicone resin having a silanol group at one end and a linear methylphenyl silicone resin having a silanol group at both ends. .
However, the linear methylphenyl silicone resin preferably has silanol groups at both ends.

A linear methylphenyl silicone resin is obtained by hydrolyzing a bifunctional silicon monomer (R ₂ Si—X ₂ ) and partially (co) condensation polymerization (where R is a methyl group or a phenyl group). And two Rs may be the same or different, and X is a hydroxyl group or a hydrolyzable group such as an alkoxy group or a chlorine atom, preferably a hydroxyl group. For example, a bifunctional silicon monomer in which two R are a methyl group and a phenyl group is hydrolyzed and partially polycondensed, or a bifunctional silicon monomer in which two R are a methyl group and two R are It is obtained by hydrolyzing a bifunctional silicon monomer that is a phenyl group and partially co-condensation polymerizing. However, the linear methylphenyl silicone resin after partial (co) condensation polymerization contains both a methyl group and a phenyl group as R.

The curable silicone resin composition of the present invention includes a curable methylphenyl silicone resin containing a trifunctional silicon unit or a curable methylphenylsilicone resin containing a bifunctional silicon unit and a trifunctional silicon unit as a curable methylphenylsilicone resin. You may contain. Hereinafter, in this specification, the curable methylphenyl silicone resin containing a trifunctional silicon unit and the curable methylphenyl silicone resin containing a bifunctional silicon unit and a trifunctional silicon unit are collectively referred to as “multifunctional curable methylphenylsilicone resin”. "
The polyfunctional curable methyl phenyl silicone resin is obtained by hydrolyzing a trifunctional silicon monomer (RSi-X ₃ ) and partially (co) condensation polymerizing, or by using a bifunctional silicon monomer (R ₂ Si-X ₂ ). It is obtained by hydrolyzing a trifunctional silicon monomer (RSi-X ₃ ) and partially cocondensation polymerizing (wherein R is a methyl group or a phenyl group, and two or more R in the silicon monomer) When present, R may be the same or different and are preferably the same, and X is a hydroxyl group or a hydrolyzable group such as an alkoxy group or a chlorine atom, and may be a hydroxyl group. preferable.). However, the polyfunctional curable methyl phenyl silicone resin after partially (co) condensation polymerization contains both methyl group and phenyl group as R.
In addition, at the time of condensation polymerization or co-condensation polymerization, a monofunctional silicon monomer (R ₃ Si—X) or a tetrafunctional silicon monomer (Si—X ₄ ) may be used in combination.

The polyfunctional curable methyl phenyl silicone resin hydrolyzes a trifunctional silicon monomer (RSi-X ₃ ) and partially (co) condensation-polymerizes, or hydrolyzes a bifunctional silicon monomer and a trifunctional silicon monomer. It is obtained by decomposing and partially copolycondensation, for example, a method of hydrolyzing trichloromethylsilane and trichlorophenylsilane and partially copolycondensation, hydrolyzing dichlorodimethylsilane and trichlorophenylsilane And partially cocondensation polymerization, dichlorodiphenylsilane and trichloromethylsilane are hydrolyzed and partially cocondensation polymerized.
The polyfunctional curable methyl phenyl silicone resin has a silanol group formed by hydrolysis of X. The polyfunctional curable methylphenylsilicone resin can be further condensed by the silanol group (can be cured), and is finally cured into a resin cured product having substantially no silanol group. The cured resin is composed of trifunctional silicon units (RSiO _3/2 ), or composed of bifunctional silicon units (R ₂ SiO) and trifunctional silicon units (RSiO _3/2 ). The cured resin may have a monofunctional silicon unit (R ₃ SiO _1/2 ) or a tetrafunctional silicon unit (SiO ₂ ).
Each silicon unit in the polyfunctional curable methylphenylsilicone resin is produced by hydrolysis of X together with each silicon unit of these resin cured products, and each silicon unit containing silanol groups contributing to the curability of the silicone resin. Also means. For example, a bifunctional silicon unit having a silanol group is represented by (R ₂ Si (OH)-), and a trifunctional silicon unit having a silanol group is represented by (RSi (OH) _2- ) or (RSi (OH) =). expressed. In addition, the molar ratio of each silicon unit in the polyfunctional curable methyl phenyl silicone resin is considered to be equal to the molar ratio of each silicon monomer as a raw material.

The polyfunctional curable methylphenylsilicone resin in the present invention is obtained by the molar ratio of trifunctional silicon units (simply the molar ratio of trifunctional silicon units) to (total of bifunctional silicon units and trifunctional silicon units) determined from Si-NMR. Also referred to as 0.4) -1.0. If the molar ratio of the trifunctional silicon unit is within the above range, the polyfunctional curable methylphenyl silicone resin is excellent in terms of heat resistance and light resistance. The molar ratio of the trifunctional silicon unit is more preferably 0.4 to 0.8, and further preferably 0.5 to 0.8.
The molar ratio of each silicon unit in the polyfunctional curable methyl phenyl silicone resin is considered to be equal to the molar ratio of each silicon monomer as a raw material. Therefore, the molar ratio of the trifunctional silicon unit in the polyfunctional curable methylphenyl silicone resin can be adjusted by adjusting the molar ratio of the silicon monomer used as the raw material.

In the polyfunctional curable methylphenylsilicone resin in the present invention, the ratio of the number of moles of phenyl groups to the number of moles of methyl groups determined from H-NMR (hereinafter referred to as “Ph / Me mole ratio”) is 0.4 to. Those of 1.2 are preferred. When the Ph / Me molar ratio is in the above range, the polyfunctional curable methylphenyl silicone resin is excellent in terms of heat resistance and workability. The Ph / Me molar ratio is more preferably 0.5 to 1.1, and still more preferably 0.5 to 1.0.
The Ph / Me molar ratio in the polyfunctional curable methyl phenyl silicone resin is considered to be equal to the Ph / Me molar ratio in each silicon monomer. Therefore, the Ph / Me molar ratio in the polyfunctional curable methylphenyl silicone resin can be adjusted by adjusting the Ph / Me molar ratio of the silicon monomer used as a raw material.

  Further, it is preferable that the polyfunctional curable methyl phenyl silicone resin is substantially composed of only a bifunctional silicon unit and a trifunctional silicon unit. Such a polyfunctional curable methyl phenyl silicone resin is not easily decomposed or discolored even when kept at a high temperature of 250 ° C. or higher for a long time, and is excellent in heat resistance.

  The polyfunctional curable methyl phenyl silicone resin can be used after being modified with an epoxy resin, a phenol resin, an alkyd resin, a polyester resin, an acrylic resin, or the like. However, the amount of the resin to be modified is preferably small, and the polyfunctional curable methyl phenyl silicone resin is preferably substantially unmodified.

The curable silicone resin composition of the present invention contains a linear methylphenyl silicone resin as an essential component as a curable methylphenyl silicone resin, and optionally contains a polyfunctional curable methylphenyl silicone resin. However, the curable methyl phenyl silicone resin preferably includes a polyfunctional curable methyl phenyl silicone resin. By containing a polyfunctional curable methylphenyl silicone resin, the adhesion to the object to be sealed is improved, the hardness of the resin cured product is increased, and the curing rate when heat-curing the curable silicone resin composition is increased. The effect of raising etc. arises. However, if the content ratio of the polyfunctional curable silicone resin is increased, curing shrinkage at the time of heat curing is increased, so that bubbles may remain in the cured resin or cracks may be generated.
In this invention, when curable methylphenyl silicone resin contains polyfunctional curable methylphenyl silicone resin, it is preferable that the ratio is more than 0 mass% and 40 mass% or less, and it is 7-40 mass%. More preferably, it is 10-35 mass%. When the ratio of the polyfunctional curable methyl phenyl silicone resin is more than 40% by mass, the curing shrinkage at the time of heat curing increases, so that the risk of bubbles remaining in the cured resin or occurrence of cracks increases.
In addition, the ratio of the linear methylphenyl silicone resin in curable methyl phenyl silicone resin is 60-100 mass%.

In the present invention, the silanol groups of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin used as the curable methylphenyl silicone resin are other components of the curable silicone resin composition, that is, metal alkoxides. And the optional fluorescent material, the mixing of the curable methyl phenyl silicone resin, the metal alkoxides, and the optional fluorescent material can be controlled uniformly and freely.
As a result, a curable silicone resin composition capable of sufficiently expressing the characteristics of the curable methylphenyl silicone resin, the metal alkoxides, and the optionally included fluorescent substance is obtained.

In the curable silicone resin composition of the present invention, the metal alkoxides act as a condensation catalyst for the curable methylphenyl silicone resin and a refractive index adjusting agent for increasing the refractive index of the cured resin. In addition, these metal alkoxides have effects such as increasing the hardness of the cured product and improving the adhesion to the object to be sealed.
The metal alkoxides in the present invention are represented by the following general formula.
M (OR) _n
In the above formula, M represents a metal element, and specifically, titanium, zirconium, aluminum, tantalum, germanium, or hafnium is exemplified.
n varies depending on M, but when M is aluminum, n = 3, when M is titanium, zirconium, germanium or hafnium, n = 4, and when M is tantalum, n = 5 is there.
OR is an alkoxy group having 8 or less carbon atoms, preferably an alkoxy group having 2 to 8 carbon atoms, and more preferably an alkoxy group having 4 to 8 carbon atoms. In addition, all the alkoxy groups couple | bonded with M may be the same, and may mutually differ. However, usually, the same alkoxy group is bonded to M.
In the present invention, oligomers of metal alkoxides represented by the above general formula can also be used. However, when using oligomers of metal alkoxides represented by the above general formula, those having a molecular weight not so large, preferably 10-mer or less, more preferably 8-mer or less are used. .

  In the curable silicone resin composition of the present invention, the metal alkoxides act as a condensation catalyst for the curable methylphenyl silicone resin. Therefore, when selecting metal alkoxides to be included in the curable silicone resin composition, it is necessary to consider the strength of the catalytic action by the metal alkoxides. That is, when the catalytic action of the metal alkoxides is too strong, the polymerization of the curable methylphenyl silicone resin becomes too fast, and each component may not be uniformly dispersed in the curable silicone resin composition. . This tendency is remarkable when the curable methyl phenyl silicone resin contains a polyfunctional curable methyl phenyl silicone resin. Therefore, when using a metal alkoxide having a strong catalytic action, particularly when using a monomer, the OR of the metal alkoxide represented by the above general formula, so that the catalytic action does not become too strong, That is, it is preferable to use an alkoxy group having a relatively large number of carbon atoms. Specifically, it is preferable to use an alkoxy group having about 4 to 8 carbon atoms. On the other hand, even if the metal alkoxide has a strong catalytic action, when an oligomer, for example, about 7 to 8 mer is used, the catalytic action is not so strong, so the carbon number of the alkoxy group is compared. It is preferable to use a small product. Specifically, it is preferable to use an alkoxy group having about 3 to 4 carbon atoms.

Specific examples of the metal alkoxides that can be contained in the curable silicone resin composition of the present invention include the following.
Titanium alkoxides Tetraisopropyl titanate (Ti (Oi-C ₃ H ₇ ) ₄ ), tetranormal butyl titanate (Ti (On-C ₄ H ₉ ) ₄ ), butyl titanate dimer ( _{(C 4 H 9 O) 3} Ti-O-Ti (OC 4 H 9) 3), butyl titanate tetramer, butyl titanate heptamer, tetra (2-ethylhexyl) titanate (Ti (OC ₈ H _{17) 4} ), Tetramethyl titanate (Ti (OCH ₃ ) ₄ )
Zirconium alkoxides <br/> zirconium tetra-n-propylate (Zr (O-n-C 3 H 7) 4), zirconium tetraisopropylate (Zr (O-i-C 3 H 7) 4), zirconium n-butyrate (Zr (O-n-C 4 H 9) 4), zirconium t- butylate (Zr (O-t-C 4 H 9) 4)
Germanium alkoxides <br/> germanium tetrachloride ethoxylate _{(Ge (C 2 H 5)} 4)
Aluminum alkoxides <br/> aluminum triisopropylate (Al (O-i-C 3 H 7) 3)
Tantalum alkoxides <br/> pentaethoxytantalum _{(Ta (C 2 H 5)} 3)
Hafnium alkoxides <br/> hafnium tetraisopropylate (Hf (O-i-C 3 H 7) 4)

  Among the above metal alkoxides, titanium alkoxides, zirconium alkoxides, and oligomers thereof are preferable because they have a high refractive index, are easy to handle because of their appropriate reactivity, and are inexpensive.

In the curable silicone resin composition of the present invention, the ratio of the metal alkoxide to the total of the curable methylphenyl silicone resin and the metal alkoxide is 1 to 30% by mass. Here, the ratio of metal alkoxides is a ratio in terms of metal oxide. Specifically, in the case of titanium alkoxide is a ratio in terms of TiO _2, when the zirconium alkoxides is the proportion in terms of ZrO _2, a ratio of the case of an aluminum alkoxide in terms of Al ₂ O _3, tantalum In the case of alkoxides, the ratio is converted to Ta ₂ O ₅ , in the case of germanium alkoxides, the ratio is converted into GeO ₂ , and in the case of hafnium alkoxides, the ratio is converted into HfO ₂ .

If the ratio of the metal alkoxide is within the above range, the catalytic action due to the addition of the metal alkoxide is sufficiently exerted, so that the curable silicone resin composition has excellent curability at the time of heat curing, while curing at the time of heat curing. There is little shrinkage. For this reason, there is a low possibility that bubbles remain in the cured resin or cracks are generated. Further, the addition of metal alkoxides gives the cured resin a refractive index of 1.48 or more (measured value with 633 nm light). When the ratio of the metal alkoxide is less than 1% by mass, the catalytic action due to the addition of the metal alkoxide cannot be exhibited, the curability at the time of heat curing is inferior, and the adhesion is insufficient. is there. In addition, the refractive index of the cured resin does not become 1.48 or more (measured value with 633 nm light). If the ratio of the metal alkoxide is more than 30% by mass, the refractive index of the cured resin can be 1.48 or more (measured value by 633 nm light), but the resin shrinks because the curing shrinkage during heat curing increases. There is an increased risk of bubbles remaining in the cured product and cracking.
The proportion of the metal alkoxide is preferably 2 to 28% by mass, more preferably 3 to 25% by mass.

The curable silicone resin composition of the present invention contains a fluorescent material as necessary. As such an application, a case where a white LED is produced by light-transparent sealing of a blue LED or a near-ultraviolet LED with a cured product of the curable silicone composition of the present invention containing a fluorescent substance can be mentioned. When the LED is transparently sealed with a cured product of a curable silicone resin composition containing a fluorescent material, the light emitted from the LED is mixed with the light emitted by exciting the phosphor with a part of this light. As a result, light having a different color from the light emitted from the LED is emitted from the light-transmitting sealed portion. Under the present circumstances, white LED can be manufactured by selecting suitably the fluorescent substance contained in a curable silicone resin composition so that white light may be emitted from the transparently sealed part. For example, when light-sealing a blue LED, if the curable silicone resin composition contains a phosphor that is excited by blue light from the LED and emits yellow light, the blue light emitted from the LED is emitted. Then, white light is emitted from the portion that is transparently sealed by mixing the yellow light emitted by exciting the phosphor with a part of the blue light. Further, when light-sealing a blue LED, the curable silicone resin composition contains a phosphor that is excited by blue light from the LED and emits green light and a phosphor that emits red light. If so, the blue light emitted from the LED and the green light and red light emitted by the phosphor being excited by a part of this blue light are mixed together and light is emitted from the light-sealed portion. Is done.
On the other hand, when a near-ultraviolet LED is transparently sealed, a phosphor that emits blue light, a phosphor that emits green light, and a phosphor that emits red light are cured by the near-ultraviolet light from the LED. If it is contained in the silicone resin composition, the blue light, green light and red light, which are excited and emitted by a part of the near-ultraviolet light from the LED, are mixed and translucently sealed. White light is emitted.

The following are mentioned as a specific example of the fluorescent substance used when light-sealing blue LED or near-ultraviolet LED and manufacturing white LED.
A phosphor that is excited by light emitted from a blue LED and emits light: A phosphor that emits yellow light:
(Y, Gd) ₃ Al ₅ O ₁₂ : Ce, Y ₃ Al ₅ O ₁₂ : Tb, Ce, Tb ₃ Al ₅ O ₁₂ : Ce, Tb ₃ Al ₅ O ₁₂ : Ce, CaGa ₂ S ₄ : Eu, ( Sr, Ca, Ba) ₃ SiO ₄ : Eu, Ca _x (Si, Al) ₁₂ (O, N) ₁₆ : Eu, α-sialon: Eu, (Ba, Sr) ₃ SiO ₅ , Li ₂ SrSi ₂ O ₄ : Eu
Phosphors that emit green light:
Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, SrGa ₂ S ₄ : Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, SrSi ₂ O ₂ N ₂ : Eu, CaAlSiN ₃ : Eu
Phosphors that emit red light:
(Sr, Ca) S: Eu, (Sr, Ca) ₂ Si ₅ N ₈ : Eu, CaSiN ₂ : Eu, CaAlSiN ₃ : Eu
A phosphor that emits light when excited by light emitted from a near-ultraviolet LED.
(Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu
Phosphors that emit green light:
_{ZnS: Cu, Al, BaMgAl 10} O 17: Eu, Mn, SrAl 2 O 4: Eu, SrGa 2 S 4: Eu, (Li, Na) TbW 2 O 8, LaPO 4: Ce, Tb
Phosphors that emit red light:
Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, LiW ₂ O ₈ : Eu, Sm, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Mn, (Ba, Sr, Ca) ₃ MgSi ₂ O ₈ : Eu, Mn, MgO.MgF ₂ .GeO ₂ : Mn, Ca (Eu _1-x La _x ) ₄ Si ₃ O ₁₃

  When the curable silicone resin composition contains a fluorescent material, the content of the fluorescent material is not particularly limited, and may be appropriately selected as necessary. When a blue LED or a near-ultraviolet LED is transparently sealed to produce a white LED, the curable silicone resin composition may contain 0.01 to 50% by mass of a fluorescent substance.

  In addition to the fluorescent substance, the curable silicone resin composition of the present invention may contain another photofunctional substance. Specific examples of the optical functional material include inorganic fillers having a light refractive index in the wavelength range from near ultraviolet light to visible light different from that of the resin cured product. Here, the light refractive index of the resin cured product refers to the light refractive index of the resin cured product not containing an inorganic filler, and a measured value by 633 nm light is used. The light refractive index of the inorganic filler is also measured using 633 nm light. When such an inorganic filler is contained in the curable silicone resin composition, the inorganic filler functions as a light scattering agent in the cured resin. Therefore, the cured resin has a light scattering function and is useful for applications such as a light diffusion plate. Specific examples of the inorganic filler include a filler made of silica, titania or alumina, and spherical silica is particularly preferable. The average particle size of the inorganic filler is preferably 1 to 10 μm. However, when such an inorganic filler is contained, the content of the inorganic filler is such that the light transmittance of the resin cured product containing the inorganic filler is 1.48 or more.

The curable silicone resin composition of the present invention can be obtained by mixing a curable methylphenyl silicone resin, a metal alkoxide, and, if necessary, a fluorescent material to obtain a uniform composition.
The curable methyl phenyl silicone resin is usually handled in a solution (varnish) dissolved in a solvent such as transport and storage. After the solvent is volatilized and removed from the varnish, the metal alkoxides and, if necessary, a fluorescent material can be mixed to produce. Since the curable silicone resin composition of the present invention contains a linear methylphenyl silicone resin that is liquid at room temperature as an essential component as a curable methyl phenyl silicone resin, the product thus produced has fluidity. A paste-like or slurry-like curable silicone resin composition is obtained.
In addition, when linear methylphenyl silicone resin and polyfunctional curable methylphenyl silicone resin are used as the curable methylphenyl silicone resin, both are mixed in advance, and then the metal alkoxide and, if necessary, the fluorescent substance are mixed. .
Although the temperature which volatilizes and removes a solvent is based also on the kind of solvent used for a varnish, it is 70-180 degreeC, Preferably it is 70-140 degreeC.

  As the curable methyl phenyl silicone resin, a methyl phenyl silicone resin obtained by partially condensing a linear methyl phenyl silicone resin and a polyfunctional curable methyl phenyl silicone resin as raw materials (hereinafter referred to as “partially condensed methyl phenyl”). It is also possible to use “phenyl silicone resin”. In the present specification, when referring to a partially condensed methylphenyl silicone resin, both a partially condensed linear methylphenyl silicone resin and a partially condensed polyfunctional curable methylphenyl silicone resin are used. means.

Partially condensed methylphenylsilicone resin undergoes a dehydration condensation reaction of the linear methylphenylsilicone resin and polyfunctional curable methylphenylsilicone resin as raw materials to some extent. There is little generation of moisture. Accordingly, as the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin, the curable silicone resin composition containing the partially condensed methylphenyl silicone resin is not partially condensed. Compared with a curable silicone resin composition containing a functional methylphenyl silicone resin, there is less risk of bubbles being generated when heat-curing. For this reason, when this curable silicone resin composition is used as a translucent sealing material, the external appearance, airtight reliability, and adhesive strength reliability of a sealing part improve.
In addition, the partially condensed methylphenyl silicone resin has less shrinkage at the time of curing as compared with the linear methylphenyl silicone resin and polyfunctional curable methylphenyl silicone resin as raw materials. Therefore, by using a partially condensed methylphenyl silicone resin as the curable methylphenylsilicone resin, the risk of bubbles remaining in the resin cured product or the occurrence of cracks is further reduced.
From the above points, it is preferable to use a partially condensed methylphenyl silicone resin as the curable methylphenyl silicone resin. In particular, when a polyfunctional curable methyl phenyl silicone resin is used as the curable methyl phenyl silicone resin, it is preferable to use a partially condensed methyl phenyl silicone resin.

  When the curable methyl phenyl silicone resin is partially condensed, the reaction is stopped to such an extent that the curing reaction by heating the resin as a raw material is not completely completed. When the linear methylphenyl silicone resin is partially condensed, the reaction is stopped to the extent that the curing reaction of the raw linear methylphenyl silicone resin is not completely completed. Similarly, when the polyfunctional curable methyl phenyl silicone resin is partially condensed, the reaction is stopped to the extent that the curing reaction of the polyfunctional curable methyl phenyl silicone resin as a raw material is not completely completed. In order to stop the reaction to such an extent that the curing reaction of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin is not completely completed, for example, heating at a lower temperature than in the case of a normal curing reaction, or Heat for a shorter time than the time required for the curing reaction. In order to partially condense the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin, for example, a curing reaction is performed at a temperature of 120 ° C. to 200 ° C., and the crosslinking reaction does not proceed, that is, gelation occurs. Stop the reaction where it is not.

The partial condensation of the linear methylphenyl silicone resin and the polyfunctional curable methylphenylsilicone resin is carried out at the stage of the resin alone before mixing the metal alkoxides and the optional fluorescent material. As described above, the metal alkoxide acts as a condensation catalyst for the curable methyl phenyl silicone resin. For this reason, when the partial condensation of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin is performed after mixing with the metal alkoxide, the curing reaction is accelerated by the catalytic action of the metal alkoxide, It is difficult to stop the reaction to such an extent that the curing reaction is not completely completed. There is also a problem that workability is inferior.
The partial condensation of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin may be performed by any of the following methods (1) to (3).
(1) Each is partially condensed before mixing them.
(2) The two are mixed and then partially condensed.
(3) After some condensing to some extent before mixing both, after mixing both, it further condenses further.

  The partial condensation of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin may be performed in the varnish state, that is, in the presence of a solvent, or after the solvent is removed from the varnish. Good. Usually, linear methylphenyl silicone resin and polyfunctional curing are carried out by volatilizing and removing the solvent from the varnish and carrying out heat treatment to remove low-boiling compounds, followed by further raising the temperature in that state. It is preferable to perform partial condensation of the functional methylphenyl silicone resin. Partial condensation of a linear methylphenyl silicone resin or a polyfunctional curable methylphenyl silicone resin can be used to stop the curing reaction before the crosslinking reaction proceeds, It is carried out at a temperature of 90 to 200 ° C. while using the viscosity of the silicone resin as a guide. In the case of the method (1) or (3), the partial condensation of the linear methylphenyl silicone resin is preferably carried out at a temperature of 170 to 200 ° C. Such condensation is preferably carried out at a temperature of 90 to 140 ° C.

  Polyfunctional curable methyl phenyl silicone resins (including partially condensed methyl phenyl silicone resins) have a higher viscosity than linear methyl phenyl silicone resins, and are high-viscosity liquids or solids with high melt viscosity at room temperature. For this reason, it is difficult to mix a linear methylphenyl silicone resin and a polyfunctional curable methylphenyl silicone resin at room temperature. Therefore, mixing of the linear methylphenyl silicone resin and the polyfunctional curable methylphenyl silicone resin is carried out in a state heated to 150 to 200 ° C.

A paste-like or slurry-like curable silicone resin composition is obtained through the above procedure. When the paste-like or slurry-like curable silicone resin composition is cured by heating, the curable methylphenylsilicone resin in the composition undergoes dehydration condensation, so that the refractive index (measured by 633 nm light) is 1.48 or more. A translucent cured product (resin cured product) is obtained.
Curing of curable methylphenyl silicone resin by dehydration condensation usually proceeds only by heating, and dehydration condensation reaction between silanol groups of the resin, more specifically, dehydration between silanol groups of linear methylphenyl silicone resin. Refraction by condensation reaction, dehydration condensation reaction between silanol groups of polyfunctional curable methylphenyl silicone resin, dehydration condensation reaction between silanol group of linear methylphenyl silicone resin and silanol group of polyfunctional curable methylphenyl silicone resin It becomes a resin cured product with a rate (measured value with 633 nm light) of 1.48 or more. At this time, it is considered that the curable methyl phenyl silicone resin and the metal alkoxide (M (OR) _n ) react to form an M—O—Si bond.

When the curable silicone resin composition of the present invention is used as a translucent sealing material, a paste-like or slurry-like curable silicone resin composition is applied to an object to be sealed, and 140 ° C or higher, preferably 150 ° C. The light-transmitting sealing is achieved only by heating and curing at a temperature of 200 to 200 ° C. for 1 to 120 minutes. However, it is necessary to volatilize and remove the alcohol generated when the metal alkoxides are hydrolyzed before using as a light-transmitting sealing material, or to volatilize and remove after applying to the object to be sealed. . The temperature to be removed by volatilization is 70 to 180 ° C, preferably 70 to 140 ° C, although it depends on the type of alcohol generated upon hydrolysis.
The method of applying the paste-like or slurry-like curable silicone resin composition to the object to be sealed is not particularly limited, and is a method of applying with a brush, spray, bar coater, dispenser, etc., potting (dropping), screen printing, etc. Various methods can be used.

In addition, the curable resin composition of the present invention is a sheet-like, wire-like, stick-like, tablet-like (spherical, hemispherical, circular) after volatilizing and removing the alcohol generated when the metal alkoxides are hydrolyzed. It may be used as a molded body formed into a shape such as a columnar shape or a shape obtained by crushing a sphere. In the case of forming a molded article, the curable silicone resin composition after volatilizing and removing the alcohol generated when the metal alkoxide is hydrolyzed is cast into a mold in a softened state by heating to 120 to 170 ° C. It can be formed with. Specifically, using molds made of fluororesin, etc., and molds treated with release material with fluororesin such as sheet or cytop, various desired shapes such as sheets, wires, sticks, tablets, etc. It can be formed into a molded body.
The molded body of the obtained curable silicone resin composition in the form of a sheet, wire, stick, tablet, etc. is placed in its shape at the site to be sealed and heated at 120 to 170 ° C. for several minutes. Then, after softening the curable silicone resin composition, it is light-transparent sealed only by heating and curing at a temperature of 140 ° C. or higher, preferably 150 ° C. to 200 ° C. for 1 to 120 minutes.

As will be described later, the curable silicone resin composition of the present invention can be preferably used as a light-transmitting sealing material for light-emitting elements such as LEDs.
In addition, the curable silicone resin composition of the present invention can be used for host materials for doping optical functional compounds, electronic components such as resistors, conductors, and dielectric electrodes formed on glass and ceramic substrates. It can also be used as an overcoat material for protecting from.

Hereinafter, the light emitting device of the present invention will be described. The light-emitting element of the present invention is a light-emitting element such as an LED, and is light-transmitted and sealed with a cured product of the curable silicone resin composition of the present invention.
FIG. 1 is a schematic view showing an example of a light emitting device of the present invention. Here, the light emitting element is an LED. The light emitting element 1 of FIG. 1 has a housing 2 made of heat resistant resin or metal. The housing 2 has a recess 2 a that also serves as a mounting substrate for the LED chip 5. Conductive lead frames 3 and 4 are fixed on the housing 2, and one end of each of the lead frames 3 and 4 is located in the recess 2a. An LED chip 5 is fixed to one end of the lead frame 3 using a die bonding agent such as a conductive paste. One end of the lead frame 4 is connected (wire bonded) to an electrode on the LED chip 5 by a bonding wire 6. The recess 2a is light-transmitted and sealed with a cured product 7 of the curable silicone resin composition of the present invention.

In order to translucently seal the recess 2a with the cured product 7 of the curable silicone resin composition of the present invention, a paste-like or slurry-like curable silicone resin composition has a desired thickness in the recess 2a. After coating, the composition may be cured by heating at 140 ° C. or higher, preferably 150 to 200 ° C. for 1 to 120 minutes. Since the cured product 7 has a refractive index (measured by 633 nm light) of 1.48 or more, the cured product 7 is excellent in light transmittance in the wavelength range from near ultraviolet light to visible light (400 nm to 800 nm). When the thickness is 100 μm, the light transmittance is 80% or more. For this reason, the light emitting element of this invention is excellent in the utilization efficiency of the light discharge | released from LED chip 5. FIG.
Further, when the light-emitting element 1 is a blue LED or a near-ultraviolet LED, a white LED can be obtained by using a curable silicone resin composition of the present invention that is applied to the recess 2a and containing a desired fluorescent substance. Can be manufactured.

  In the light-emitting element 1 shown in FIG. 1, as the heat-resistant resin or metal housing 2, for example, a ceramics housing such as alumina, aluminum nitride, or silicon carbide, a glass ceramic housing, or a silicon oxide film on the surface A silicon housing (silica coated silicon housing) in which is formed can be used.

  When manufacturing a white LED, the LED is preferably a blue LED or a near-ultraviolet LED. The blue LED is an LED having a main emission peak wavelength of 400 to 500 nm, and examples thereof include nitride semiconductors such as GaN and InGaN, or II-VI group compound semiconductors such as ZnO and ZnS. The near-ultraviolet LED is exemplified by an LED having a main emission peak wavelength of 370 to 420 nm.

However, FIG. 1 shows an example of the light-emitting element of the present invention, and the light-emitting element of the present invention is not limited to this. For example, the connection between the lead frame 3 and the LED chip 5 may not be wire bonding, but may be flip-chip bonding or wireless bonding using a non-conductive film (Non-Conductive Film).
Moreover, the light emitting element may use a semiconductor laser instead of the LED. In order to obtain white light using a semiconductor laser, a semiconductor laser having a main emission peak wavelength of 350 to 500 nm, more specifically, a nitride semiconductor such as GaN and InGaN, or a II-VI group compound semiconductor such as ZnO and ZnS A semiconductor laser using the above can be used.

(Examples 1 to 10)
In Examples 1 to 10, only a linear methylphenyl silicone resin was used as the curable methyl phenyl silicone resin.
While stirring a linear methylphenyl silicone resin having a silanol group at both ends (product name: YF3804, manufactured by Toshiba GE) at 180 ° C. for 5 hours under reduced pressure, the low boiling point compounds are volatilized and removed. A partially condensed methylphenyl silicone resin (A) was obtained by partially condensing a linear methylphenyl silicone resin. The partially condensed methylphenyl silicone resin (A) is liquid at normal temperature.

The obtained partially condensed methylphenyl silicone resin (A) and titanium alkoxide were mixed according to the ratios shown in Table 1, and stirred uniformly to obtain a transparent paste-like curable silicone resin composition. It was. In addition, as titanium alkoxide, monomer (tetra (2-ethylhexyl) titanate, Ti (OC ₈ H ₁₇ ) ₄ ), dimer (butyl titanate dimer, (C ₄ H ₉ O) ₃ Ti—O _{-Ti (C 4 H 9 O)} 3) 4 -mer (butyl titanate _{tetramer, (C 4 H 9 O)} 3 Ti- [O-Ti (C 4 H 9 O) 2] 2 -OTi (C 4 H ₉ O) ₃₎ or 7-mer (butyl titanate _{heptamer, (C 4 H 9 O)} 3 Ti- [O-Ti (C 4 H 9 O) 2] 5 -OTi (C 4 H 9 O) ₃ ) Any one of them was used.

The following evaluation was performed about the obtained paste-like curable silicone resin composition. The results are shown in Table 1.
Evaluation of thermal decomposability The obtained curable silicone resin composition was applied to an aluminum cup so as to have a thickness of 100 to 200 μm, at 120 ° C. for 15 minutes, at 150 ° C. for 15 minutes, at 180 ° C. for 30 minutes, at 200 ° C. The composition was cured by stepwise heating in order of 30 minutes to obtain a test sample. The mass loss when the obtained test sample was heated from 50 ° C. to 200 ° C. was measured using a thermobalance (TGA, manufactured by TA Instruments). The measurement was performed in dry air, and the heating rate was 10 ° C./min. The evaluation criteria for evaluation of thermal decomposability are as follows.
○: Mass reduction when heated to 50 ° C.-200 ° C. is 1.5% or less.
X: The mass reduction | decrease at the time of heating to 50 to 200 degreeC exceeds 1.5%.

Refractive index evaluation The obtained curable silicone resin composition was applied on a glass or quartz substrate, and stepwise in order of 15 minutes at 120 ° C, 15 minutes at 150 ° C, 30 minutes at 180 ° C, and 30 minutes at 200 ° C. The composition was cured by heating to obtain a test sample. The refractive index at a wavelength of 633 [nm] of the obtained test sample was measured with a prism coupler (manufactured by Metricon). The measurement was performed at room temperature in air.

Evaluation of UV absorption characteristics The obtained curable silicone resin composition was applied on a quartz or calcium fluoride substrate, 15 minutes at 120 ° C, 15 minutes at 150 ° C, 30 minutes at 180 ° C, and 30 minutes at 200 ° C. The composition was cured by stepwise heating to obtain a test sample. In order to evaluate the UV absorption characteristics of the obtained test sample, the light transmittance of the test sample was measured with a spectrophotometer (Hitachi U-3500). The measurement was carried out in air at room temperature. As an evaluation result, Table 1 shows the wavelength of the absorption edge (the wavelength at which the light transmittance is 50% of the light transmittance at a wavelength of 600 [nm]).

Phosphor emission characteristics evaluation After the phosphor was kneaded and dispersed in the obtained curable silicone resin composition, it was applied on a glass or quartz substrate, and the coating was applied at 120 ° C for 15 minutes, 150 ° C for 15 minutes, and 180 ° C for 30 minutes. The composition was cured by stepwise heating at 200 ° C. for 30 minutes to obtain a test sample. As a phosphor, a phosphor that emits yellow light when excited by blue light (Y ₃ Al ₅ O ₁₂ : a part of Y in Ce is substituted with Gd) (Product name: P46-Y3, Chemical Optonics) Used). The amount of phosphor added was 5 wt% with respect to the total mass of the curable silicone resin composition and the phosphor. The emission characteristics of the phosphor were measured using a fluorescence spectrophotometer (Hitachi, F-4500). The evaluation criteria for the phosphor emission characteristics are as follows.
○: No significant change is observed in the emission spectrum of the phosphor.
X: A remarkable change is recognized in the emission spectrum of the phosphor.

Evaluation of sealing characteristics and light emitting characteristics of light emitting element The phosphor was kneaded and dispersed in the curable silicone resin composition in the same procedure as the phosphor light emitting characteristics evaluation described above. The obtained composition was potted (dropped) into the recess 2a of the housing 2 shown in FIG. Thereafter, the composition is cured by stepwise heating in order of 120 ° C. for 15 minutes, 150 ° C. for 15 minutes, 180 ° C. for 30 minutes, and 200 ° C. for 30 minutes, whereby the light emitting device (LED) 1 is obtained. Produced. The housing 2 is made of alumina, and the LED chip 5 is a blue LED.
The sealing characteristics of the obtained light emitting device 1 were evaluated according to the following evaluation criteria.
○: Adhesiveness between the cured product 7 of the composition and the structure on the housing 2 and the recess 2a (that is, the lead frames 3 and 4, the LED chip 5, and the bonding wire 6) is good in the light emitting element 1. .
X: Adhesiveness between the cured product 7 of the composition and the structure on the housing 2 and the recess 2a is inferior, and the cured product 7 is easily peeled off.
Moreover, the light emission characteristic of the obtained light emitting element 1 was evaluated according to the following evaluation criteria.
○: When a voltage is applied to the LED chip 5, white light emission can be confirmed.
X: When a voltage is applied to the LED chip 5, bluish light emission can be confirmed.
The results of these evaluations are shown in Table 1.

(Examples 11 to 20)
In Examples 9 to 16, a linear methylphenyl silicone resin and a polyfunctional curable methylphenylsilicone resin were used as the curable methylphenylsilicone resin.
Preparation of polyfunctional curable methylphenyl silicone resin Multifunctional curing with a trifunctional silicon unit molar ratio of 0.7 (measured by Si-NMR) and a Ph / Me molar ratio of 0.6 (measured by H-NMR) The varnish containing the functional methylphenyl silicone resin is heated at 120 ° C. under reduced pressure for 1 hour with stirring to volatilize and remove the solvent of the varnish, and the polyfunctional curable methylphenyl silicone resin is partially condensed. Partially condensed methylphenyl silicone resin (B) was obtained. The partially condensed methylphenyl silicone resin (B) is solid at room temperature.
The partially condensed methyl phenyl silicone resin (A) was mixed at a ratio of 80 wt% and the partially condensed methyl phenyl silicone resin (B) at a ratio of 20 wt% under reduced pressure at 170 ° C., and the mixture was further stirred for 1 hour so that both were uniform. Both were further partially condensed to obtain a partially condensed methylphenyl silicone resin (C). The partially condensed methylphenyl silicone resin (C) is a highly viscous liquid at normal temperature.

In the same procedure as described for Examples 1 to 10, the obtained partially condensed methylphenylsilicone resin (C) and titanium alkoxide were mixed according to the ratio described in Table 2, and stirred uniformly. A transparent curable silicone resin composition was obtained.
The obtained curable silicone resin composition was subjected to thermal decomposition evaluation, refractive index evaluation, UV absorption characteristic evaluation, phosphor light emission characteristic evaluation, and LED light emission characteristic evaluation in the same procedure as described in Examples 1 to 10. did. The results are shown in Table 2.

(Examples 21 to 23)
Refractive index evaluation and UV absorption characteristic evaluation were performed on the partially condensed methylphenyl silicone resins (A) and (B) and linear dimethyl silicone having silanol groups at both ends (both ends silanol). The results are shown in Table 3.
However, in the case of the curable silicone resin composition of Example 21, since the curing shrinkage at the time of heat curing is large, the cured film is cracked or the cured film is peeled off. Refractive index evaluation and UV absorption characteristic evaluation could not be performed on the film. The results of refractive index evaluation and UV absorption characteristic evaluation of Example 21 shown in Table 3 relate to an uncured (not heat-cured) film. In the refractive index evaluation of Example 21, the obtained curable silicone resin composition was applied on a glass or quartz substrate and then heated to 150 ° C. and repeatedly softened and depressurized while the composition was softened. After smoothing the surface of the composition film coated on the substrate, it was carried out in the same procedure as described for Examples 1 to 10 except that a test sample obtained by cooling to room temperature was used. . On the other hand, the UV absorption property evaluation was performed in the same procedure as described for Examples 1 to 10 except that an uncured (not heat-cured) curable silicone resin composition was used.
About Examples 22 and 23, refractive index evaluation and UV absorption characteristic evaluation were implemented in the following procedures.
Refractive Index Evaluation The refractive index at a wavelength of 589 [nm] of the obtained liquid curable silicone resin composition was measured with an Abbe refractometer 2T (manufactured by Atago Co., Ltd.). The measurement was carried out by dropping the curable silicone resin composition in the center of the main prism surface, covering the sub-prism thereon, and forming a thin film of the curable silicone resin composition between the main prism and the sub-prism.
Evaluation of UV Absorption Characteristics Using the test sample obtained by injecting the obtained liquid curable silicone resin composition into a quartz cell, the same procedure as described for Examples 1 to 10 was performed.

FIG. 1 is a schematic view showing an example of a light emitting device of the present invention.

Explanation of symbols

1: Light-emitting element 2: Housing 2a: Concave portion 3, 4: Lead frame 5: LED chip 6: Bonding wire 7: Cured product of curable silicone resin composition

Claims (7)

A curable methylphenyl silicone resin in which the proportion of a linear methylphenyl silicone resin having one or both ends of a silanol group is 60 to 100% by mass;
Metal alkoxides, and
Curability in which the ratio of metal alkoxides to the total of the curable methylphenyl silicone resin and the metal alkoxides (however, the ratio of metal alkoxides is a ratio converted to metal oxide) is 1 to 30% by mass. A silicone resin composition comprising:
A curable silicone resin composition in which the cured product becomes a translucent cured product having a refractive index (measured by 633 nm light) of 1.48 or more. The curable methyl phenyl silicone resin contains a trifunctional silicon unit or a polyfunctional curable methyl phenyl silicone resin containing a trifunctional silicon unit and a bifunctional silicon unit in an amount of more than 0% by mass and 40% by mass or less,
The curable silicone according to claim 1, wherein a molar ratio of the trifunctional silicon unit to the total of the trifunctional silicon unit and the bifunctional silicon unit in the polyfunctional curable methylphenyl silicone resin is 0.4 to 1.0. Resin composition.   The curable silicone resin composition according to claim 2, wherein a molar ratio of phenyl groups to methyl groups in the polyfunctional curable methylphenyl silicone resin is 0.4 to 1.2.   The curable silicone resin composition according to any one of claims 1 to 3, wherein the metal alkoxide is at least one selected from the group consisting of titanium alkoxides, zirconium alkoxides and oligomers thereof.   Furthermore, the curable silicone resin composition in any one of Claim 1 thru | or 4 containing a fluorescent material.   The translucent sealing material which consists of a curable silicone resin composition in any one of Claims 1-5.   The light emitting element light-transparent-sealed with the hardened | cured material of the curable silicone resin composition in any one of Claims 1-5.

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