JP4853630B2 - Curable resin composition - Google Patents

Description

  The present invention relates to a curable resin composition useful for sealing an optical element.

  Conventionally, a bisphenol A glycidyl ether type epoxy resin has been used as an LED sealing resin, but this resin is inferior in heat resistance and light resistance (particularly, light resistance to UV and blue light), and is used for high-intensity LEDs and When used in a UV emitting LED or the like, the color is changed by heat or light emitted from the LED. Therefore, there exists a problem that the brightness | luminance of LED changes with time.

  To solve this problem, highly transparent epoxy resins have been developed, but sufficient heat resistance and light resistance have not yet been obtained.

  On the other hand, gel type silicone resins are used for high-brightness LEDs because they are superior in heat resistance and light resistance compared to epoxy resins.

  However, the gel type silicone resin has the following problems.

  First, there is a problem that the surface is sticky and dust and dust are likely to stick. For this reason, silicone resin is currently used only as a resin that fills the gap between the dome part having a lens function and the LED chip base part, or as a sealing resin when the LED is surface-mounted. It has been.

  Secondly, since the refractive index of silicone resin is smaller than that of epoxy resin and is 1.41 to 1.51, the light extraction efficiency from the LED is inferior. That is, in a high-brightness LED, a sapphire substrate is often used as the chip substrate, and a method of taking out light from the sapphire substrate side is the mainstream. Since the refractive index of sapphire is 1.76, in order to efficiently extract light from the sapphire substrate to the sealing resin, the refractive index of the sealing resin is preferably close to 1.76 which is the refractive index of sapphire. However, the refractive index of a silicone resin is 1.41 for a general dimethyl silicone resin, and about 1.51 for a diphenyldimethyl-based or phenylmethyl-based silicone resin whose refractive index is increased by introducing a phenyl group. In both cases, the refractive index of the epoxy resin is lower than 1.53 to 1.57. Therefore, when a silicone resin is used as a sealing resin for a high-brightness LED, the light extraction efficiency is inevitably inferior to that when an epoxy resin is used.

  Thirdly, since the silicone resin used for the electronic material is an addition reaction type and has two components, there is a restriction that the two components must be mixed immediately before use. Usually, a static mixer is used for mixing the two liquids. However, since this mixer can only mix those having a relatively low viscosity, it is difficult to obtain a resin composition after mixing the two liquids with a sufficiently high viscosity. Therefore, it cannot be molded into a predetermined lens shape, and a lens function cannot be imparted to the sealing resin.

  Among the problems of such silicone resins, a method to increase the refractive index of the resin composition by adding fine particles of high refractive index such as titanium oxide, zirconium oxide, zinc oxide, etc. to the resin is proposed. (Patent Document 1). However, in order to increase the refractive index of the silicone resin by this method compared with the epoxy resin, the fine particles must be added to the resin at a ratio of at least 10 to 40% by volume. In addition, it is difficult to obtain the fluidity necessary for use as a sealing resin. Although there are attempts to improve transparency by using fine particles called single nanosize, single nanosize ultrafine particles have extremely high cohesive strength and can be uniformly dispersed in the resin without forming secondary agglomerated particles. It is extremely difficult to disperse. Therefore, a technique for sealing an LED with a resin using such fine particles has not been put into practical use.

  On the other hand, it has been proposed to use a fluorene group-containing monoacrylate as a high refractive index resin used in the production of an optical antireflection film (Patent Document 2), and it is considered to use this compound as an LED sealing resin. It is done.

  However, since the fluorene group-containing monoacrylate has a very high viscosity, it is inferior in handleability as a sealant. For example, when a low viscosity diluent such as 2-hydroxyethyl acrylate is added to the fluorene group-containing monoacrylate, the viscosity of the composition can be reduced, but the problem of a decrease in the refractive index due to the use of the diluent is a problem. Arise. In addition, this composition is very hard after curing, and when used as an LED sealing resin, problems such as peeling between the chip and the resin due to thermal stress, damage to the chip, or disconnection of the wiring Occurs.

JP 2004-15063 A JP 2002-293762 A

  In response to the above-described problems of the prior art, the present invention is a resin composition having a viscosity suitable for forming an LED sealing resin, and its cured product has a refractive index at least equal to or higher than that of an epoxy resin. It has excellent heat resistance and light resistance, has an appropriate viscosity, and in an LED sealed using this, the cured product has an extent that does not cause trouble such as peeling of the sealing resin, breakage of the chip, disconnection, etc. An object of the present invention is to provide a resin composition having low hardness, and to provide a cured product of such a resin composition and an optical element sealed with the cured product.

  The inventors of the present invention have a resin composition comprising a specific bifunctional acrylate or methacrylate having fluorene and a specific monofunctional acrylate or methacrylate, which is a one-component curable resin composition having an appropriate viscosity, The refractive index of the cured product was 1.55 or more, equal to or higher than that of the epoxy resin, and was found to have excellent heat resistance and light resistance, and also had a hardness suitable as a sealing resin, thereby completing the present invention.

That is, the present invention provides a curable resin composition containing a fluorene group-containing acrylate or methacrylate represented by the following formula (1) and a monofunctional acrylate or methacrylate represented by the following formula (2) or (3). provide.

（式中、Ｘ：-(ＣＨ₂ＣＨ₂Ｏ)_n- 又は-(ＣＨ₂ＣＨ₂Ｏ)_n-ＣＨ₂ＣＨ(ＯＨ)ＣＨ₂Ｏ- 、
ｎ＝１〜５
Ｒ：アクリル又はメタクリル ）

Wherein X: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ O) _n —CH ₂ CH (OH) CH ₂ O—
n = 1-5
R: Acrylic or methacrylic)

（式中、Ａ：アクリル又はメタクリル
Ｘ：フェニル、クミルフェニル、ビフェニル、テルフェニル又は
多環式芳香族炭化水素基
Ｙ：-(ＣＨ₂ＣＨ₂Ｏ)_n- もしくは-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n- 但しｎ＝１〜５、又は
-(ＣＨ₂ＣＨ₂Ｏ)_n1-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n2- 、ｎ1＋ｎ2＝２〜５）

(In the formula, A: acrylic or methacryl X: phenyl, cumylphenyl, biphenyl, terphenyl or
Polycyclic aromatic hydrocarbon group Y: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ CH ₂ O) _n — where n = 1 to 5, or
_{- (CH 2 CH 2 O)} n1 - (CH 2 CH 2 CH 2 O) n2 -, n1 + n2 = 2~5)

（式中、Ａ：アクリル又はメタクリル
Ｘ：フェニル、クミルフェニル、ビフェニル、テルフェニル又は
多環式芳香族炭化水素基
Ｙ：-(ＣＨ₂ＣＨ₂Ｏ)_n- もしくは-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n- 、ｎ＝１〜５、又は
-(ＣＨ₂ＣＨ₂Ｏ)_n1-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n2- 、ｎ1＋ｎ2＝２〜５）
Ｒ：ＣＨ₃、Ｂｒ又はＩ、ｍ＝１〜６）
また、本発明は、この硬化性樹脂組成物を硬化させてなる硬化物、特に、この硬化性樹脂組成物を用いて封止されてなる発光素子を提供する。

(In the formula, A: acrylic or methacryl X: phenyl, cumylphenyl, biphenyl, terphenyl or
Polycyclic aromatic hydrocarbon group Y: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ CH ₂ O) _n −, n = 1 to 5, or
_{- (CH 2 CH 2 O)} n1 - (CH 2 CH 2 CH 2 O) n2 -, n1 + n2 = 2~5)
R: CH ₃ , Br or I, m = 1-6
The present invention also provides a cured product obtained by curing the curable resin composition, particularly a light-emitting device that is sealed using the curable resin composition.

  According to the present invention, the following effects can be obtained.

  1stly, since the resin composition of this invention is 1 liquid property which can be hardened | cured easily with a heat | fever or UV irradiation, there is no restriction | limiting in usable time. Moreover, viscosity adjustment is possible and it can adjust to the viscosity according to a use. Therefore, the resin composition of the present invention is excellent in handleability.

  Secondly, the cured product of this resin composition has a dry touch with no stickiness on the surface and has a self-shape retaining property. For this reason, this hardened | cured material exhibits a lens function in addition to a sealing function.

  Thirdly, this cured product is not as hard as a cured product of fluorene group-containing monoacrylate, can have a glass transition point (Tg) of 100 ° C. or less, and has thermal stress relaxation properties. Therefore, thermal stress is not applied to the LED chip, and problems of chip degradation due to poor sealing and disconnection due to thermal stress can be solved.

  Fourth, the refractive index of the cured product is 1.55 or more, which is equal to or higher than that of the epoxy resin, and the light extraction efficiency from the sapphire substrate of the LED can be improved.

  Fifth, this cured product is excellent in heat resistance and light resistance and can maintain transparency. Therefore, according to this hardened | cured material, it becomes possible to reduce the time-dependent change of the emitted light quantity at the time of sealing high-intensity LED.

  Hereinafter, the present invention will be described in detail. In the following description, (meth) acrylate means acrylate or methacrylate.

  The resin composition of the present invention has the following formula (1)

（式中、Ｘ：-(ＣＨ₂ＣＨ₂Ｏ)_n- 又は-(ＣＨ₂ＣＨ₂Ｏ)_n-ＣＨ₂ＣＨ(ＯＨ)ＣＨ₂Ｏ- 、
ｎ＝１〜５
Ｒ：アクリル又はメタクリル ）

で表されるフルオレン基含有（メタ）アクリレートを含有する。

Wherein X: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ O) _n —CH ₂ CH (OH) CH ₂ O—
n = 1-5
R: Acrylic or methacrylic)

The fluorene group containing (meth) acrylate represented by these is contained.

  The compound of the formula (1) has a refractive index before curing of 1.57 to 1.62, a refractive index after curing of 1.58 to 1.65, and has a refractive index equal to or higher than that of an epoxy resin, Moreover, it is a compound excellent in heat resistance and light resistance. In formula (1), if n exceeds 5, the refractive index becomes too small, which is not preferable.

As the (meth) acrylate of the formula (1), a commercially available product can be used. For example, 9,9′-bis (4- (2-acryloxyethoxy) phenylfluorene) of the following formula (1a) (Osaka Gas Chemical Company, BPEF-A) (refractive index 1.614),

Use 9,9'-bis (4- (2- (3-acryloyl-2-hydroxypropoxy) ethoxy) phenyl) fluorene (Osaka Gas Chemical Company) (refractive index 1.574) of the following formula (1b) Can do.

  In the resin composition of this invention, the fluorene group containing (meth) acrylate of Formula (1) can contain 1 type or multiple types.

  The single composition of the fluorene group-containing (meth) acrylate of formula (1) has a high viscosity and is not suitable for applications such as thin film coating, printing, and injection. Therefore, in the present invention, the following formula (2)

（式中、Ａ：アクリル又はメタクリル
Ｘ：フェニル、クミルフェニル、ビフェニル、テルフェニル又は
多環式芳香族炭化水素基
Ｙ：-(ＣＨ₂ＣＨ₂Ｏ)_n- もしくは-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n- 、ｎ＝１〜５、又は
-(ＣＨ₂ＣＨ₂Ｏ)_n1-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n2- 、ｎ1＋ｎ2＝２〜５）
で表される単官能（メタ）アクリレート、又は次式（３）

(In the formula, A: acrylic or methacryl X: phenyl, cumylphenyl, biphenyl, terphenyl or
Polycyclic aromatic hydrocarbon group Y: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ CH ₂ O) _n −, n = 1 to 5, or
_{- (CH 2 CH 2 O)} n1 - (CH 2 CH 2 CH 2 O) n2 -, n1 + n2 = 2~5)
Or a monofunctional (meth) acrylate represented by the following formula (3)

（式中、Ａ：アクリル又はメタクリル
Ｘ：フェニル、クミルフェニル、ビフェニル、テルフェニル又は
多環式芳香族炭化水素基
Ｙ：-(ＣＨ₂ＣＨ₂Ｏ)_n- もしくは-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n- 、ｎ＝１〜５、又は
-(ＣＨ₂ＣＨ₂Ｏ)_n1-(ＣＨ₂ＣＨ₂ＣＨ₂Ｏ)_n2- 、ｎ1＋ｎ2＝２〜５）
Ｒ：ＣＨ₃、Ｂｒ又はＩ、ｍ＝１〜６）

で表される単官能（メタ）アクリレートを併用する。

(In the formula, A: acrylic or methacryl X: phenyl, cumylphenyl, biphenyl, terphenyl or
Polycyclic aromatic hydrocarbon group Y: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ CH ₂ O) _n −, n = 1 to 5, or
_{- (CH 2 CH 2 O)} n1 - (CH 2 CH 2 CH 2 O) n2 -, n1 + n2 = 2~5)
R: CH ₃ , Br or I, m = 1-6

A monofunctional (meth) acrylate represented by

  In the formulas (2) and (3), examples of the polycyclic aromatic hydrocarbon of X include naphthalene, dinaphthalene, anthracene, and pyrene.

  As the monofunctional (meth) acrylate of the formula (2) or (3), a commercially available product can be used. For example, paracumylphenoxyethyl acrylate (Toagosei Co., Aronix M110) (monomer refractive index 1.5542, Viscosity 125 mPa),

2- (2-Acryloxyethoxy) biphenyl (Toa Gosei Co., Ltd., TO1463) (monomer refractive index 1.5785, viscosity 125 mPa)

Phenoxyethyl acrylate (Osaka Organic Chemical Industry Co., Ltd., Biscoat V192) (polymer Tg. −22 ° C., monomer refractive index 1.519, viscosity 9.7 mPa)

等がある。

Etc.

  In the present invention, the monofunctional (meth) acrylate of formula (2) or (3) may be used alone or in combination of two or more.

  The monofunctional (meth) acrylate of the formula (2) or (3) has a viscosity (E-type viscometer, 25 ° C.) in the range of several tens to several thousand mPa, and this is converted to the above-mentioned fluorene group-containing (meth) acrylate. The blended resin composition has a viscosity of 100 to 100,000 mPa, and has a viscosity suitable for applications such as thin film coating, printing, and injection.

  The monofunctional (meth) acrylate of the formula (2) or (3) has a benzene skeleton and has good compatibility with the fluorene group-containing (meth) acrylate of the formula (1). Moreover, the monofunctional (meth) acrylate of the formula (2) or (3) has a high refractive index of 1.5 or more, and even if the blending amount is increased, the refractive index of the final cured product can be kept high. Is possible. Therefore, the monofunctional (meth) acrylate of the formula (2) or (3) has a high degree of freedom in the blending amount, and the specific blending amount thereof is changed to the fluorene group-containing (meth) acrylate of the formula (1). It can be appropriately determined according to the viscosity, refractive index, etc. required for the resin composition obtained by blending. For example, when high heat resistance of about 150 ° C. × 240 hours is required, the monofunctional (meth) acrylate of formula (2) or (3) and the fluorene group-containing (meth) acrylate of formula (1) Is preferably about 0.2: 1 to 1: 1. When a large amount of the monofunctional (meth) acrylate of the formula (2) or (3) is used, the heat resistance is lowered.

  In order to set the glass transition point (Tg) of the cured product to 100 ° C. or less and to impart sufficient thermal stress relaxation properties to the cured product, the blending weight of the monofunctional (meth) acrylate of the formula (2) or (3) ( The ratio (W1 / W0) between W1) and the blended weight (W0) of the fluorene group-containing (meth) acrylate of formula (1) is preferably 0.5 or more.

  In this case, when the refractive index of the resin composition is 1.58 or more, the monofunctional (meth) acrylate of the formula (2) or (3) and the fluorene group-containing (meta) of the formula (1) ) The blending weight ratio with the acrylate is preferably 0.2: 1 to 2: 1, more preferably 0.5: 1 to 1: 1.

  In addition, by using together the monofunctional (meth) acrylate of Formula (2) or (3), transparency, light resistance, curing speed, etc. can be adjusted in addition to the refractive index and the physical properties of the cured product.

  If necessary, the resin composition of the present invention contains various monomers for adjusting physical properties such as the curing speed, viscosity, refractive index of the cured product, transparency, light resistance, and heat resistance. be able to. However, it is preferable not to include a monomer containing sulfur because it has a problem of yellowing due to heat.

  Examples of the monomer that can be preferably contained in the resin composition of the present invention include aromatic vinyl monomers such as styrene for the purpose of low viscosity.

  Moreover, in order to make Tg of hardened | cured material low and to provide a softness | flexibility to hardened | cured material, the monomer which reduces Tg of a resin composition can be mix | blended. Such monomers include butyl acrylate, 2-ethylhexyl acrylate, 2-methoxy acrylate, 3-methoxybutyl acrylate, and the like. These generally have a refractive index of 1.45 or less, and if they are blended in a large amount, the cured product of the present invention cannot have a refractive index of 1.55 or more. Therefore, the blending amount of these monomers is usually preferably 50% by weight or less.

  In order to increase the transparency of the cured product, a monomer that lowers the cutoff frequency can be blended. By lowering the cutoff frequency, the cured product becomes transparent to UV light and blue light emitted from the LED, and these lights are not absorbed by the cured product. Therefore, it is preferable because loss of luminance can be prevented, the cured product can be prevented from being deteriorated by these lights, and transparency can be stably maintained over a long period of time. Examples of such monomers include cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, and the like.

  As the curing agent of the resin composition of the present invention, radical curing agents such as peroxides and azo compounds, UV curing agents and the like can be used. The blending amount is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of monomers.

  Moreover, in order to further raise the refractive index of hardened | cured material, the high refractive index ultrafine particle can be mix | blended with the resin composition of this invention. Here, the high refractive index ultrafine particles are made of a metal oxide such as titanium oxide, zirconium oxide, zinc oxide, aluminum oxide, and magnesium oxide, and have a particle diameter called a single nanosize having a diameter of 20 nm or less, more preferably 9 nm or less. Transparent fine particles having a refractive index of 1.6 or more. As the high refractive index ultrafine particles, the surface is preferably subjected to hydrophobic treatment.

  In addition, the resin composition of the present invention can contain a polymerization inhibitor and other various additives. For example, 25-1000 ppm of hydroquinone, methoquinone, BHT, etc. can be blended as a polymerization inhibitor. As a thixotropic agent, silicon oxide fine particles such as aerosol can be blended. In order to convert the emission wavelength of the LED, a coloring dye, a YAG phosphor or the like may be blended.

In the resin composition of the present invention, a fluorene group-containing (meth) acrylate represented by the formula (1), a monofunctional (meth) acrylate represented by the formula (2) or (3), and components to be added as necessary are used in a conventional manner. Can be obtained as a liquid composition.

  This resin composition can be cured by heating at a temperature of 80 to 150 ° C. or UV irradiation. Further, it can be suitably used as a curable resin composition for optical sealing of light emitting elements such as LEDs, optical disks, and lasers. Therefore, this invention includes the light emitting element sealed with the resin composition of this invention.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

Example 1
(1) Preparation of resin composition
80 parts by weight of 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene (Osaka Gas Chemical Company, trade name BPEF-A) and paracumylphenoxyethyl acrylate (Toagosei Co., Ltd., trade name Aronix M110) 20 Part by weight was blended, uniformly mixed at 60 ° C., and cooled to 40 ° C. Next, 1 part by weight of a curing agent (manufactured by NOF Corporation, Perhexa O) was blended and dispersed uniformly using a planetary mixer to obtain a resin composition.

(2) Production of cured product sheet The resin composition of (1) was sandwiched between two release films made of PET, the thickness was adjusted, and it was cured by heat treatment in an oven at 80 ° C. for 1 hour. After returning to room temperature, the release film was removed to obtain a cured sheet having a thickness of 0.5 mm.

(3) Evaluation The following evaluation was performed with respect to the above-mentioned resin composition and cured material sheet. The results are shown in Table 1.

(3-1) Viscosity The viscosity of the resin composition was measured with an E-type viscometer (25 ° C.).

(3-2) Refractive Index The refractive indexes of the resin composition and the cured product sheet described above were measured using Abbe's refractometer (sodium D line (589 nm), 25 ° C.).

(3-3) Cut-off wavelength The cured product sheet was used as a sample piece, and the cut-off wavelength was examined with a spectrophotometer. As a result, the cut-off wavelength of the cured product sheet was 325 nm. In addition, it is practically required that the cutoff wavelength is sufficiently lower than 440 ± 20 nm, which is the emission wavelength of the blue LED.

(3-4) Light extraction efficiency (total light emission ratio)
First, an LED chip base (bear chip and its pedestal) is obtained by removing the lens portion and sealing resin of a commercially available green LED (Luxeon made by Lumilets), and this LED chip base is caused to emit light in an integrating sphere. The current value was adjusted so that the light emission amount was 17 lumens.

  Next, a mold having a hemispherical depression shape with a diameter of 5 mm is used, and the resin composition described above is poured into the depression, and the LED chip base is placed thereon so that the chip base is in contact with the resin composition. The resin composition was cured by placing it downward and heat-treating it in an oven at 80 ° C. for 1 hour. The LED element which has a transparent hemispherical dome was obtained by taking out from a metal mold | die after cooling to room temperature, The total light-emission amount was measured using the integrating sphere. As a result, it was 38 lumens.

  As the light extraction efficiency, a ratio between the total light emission amount of the LED element thus obtained and the total light emission amount of the bare chip was obtained.

  In the LED element, the light extraction efficiency increases as the refractive index of the resin constituting the hemispherical dome approaches the refractive index of the sapphire constituting the LED chip substrate.

(3-5) Glass transition point (Tg)
The glass transition point of the cured product sheet was measured with a dynamic viscoelasticity measuring device Leo Vibron (Orientec, DDV-25FP).

(3-6) Shore A hardness Based on ASTM D2240, the Shore A hardness (room temperature) of the cured sheet was measured using a type A durometer.

(3-7) Light Resistance Test Using a cured sheet as a sample piece, a light resistance test for 96 hours with a fade meter was performed based on JIS A1415, and the presence or absence of a color change was examined visually.

(3-8) Heat resistance test Using a cured sheet as a sample piece, a heat resistance test was conducted for 96 hours in an air atmosphere at 150 ° C, and the presence or absence of a change in transparency before and after that was visually examined.

Examples 2-6
The compounding amount of 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene and paracumylphenoxyethyl acrylate was changed as shown in Table 1, and Ciba Specialty Chemicals, Irgacure I-651 was used as a curing agent. A resin composition was prepared in the same manner as in Example 1 except that a cured product sheet was prepared by irradiating the obtained resin composition with an accumulated light amount of 1 J / cm ² with a halogen lamp. Were made and evaluated. The results are shown in Table 1.

Examples 7-11
A resin composition was prepared in the same manner as in Example 2 except that 2- (2-acryloxyethoxy) biphenyl (trade name TO1463, manufactured by Toagosei Co., Ltd.) was used in the blending amount shown in Table 1 instead of paracumylphenoxyethyl acrylate. The cured product sheet was prepared from the resin composition obtained and evaluated. The results are shown in Table 1.

Examples 12-13
An acrylic composition was prepared in the same manner as in Example 2 except that phenoxyethyl acrylate (Osaka Organic Chemical Co., Ltd., trade name Viscoat V192) was used in the blending amount shown in Table 1 instead of paracylphenoxyethyl acrylate, A cured product sheet was prepared from the obtained acrylic composition and evaluated. The results are shown in Table 1.

Comparative Example 1
To 100 parts by weight of a commercially available bisphenol A type epoxy resin (Japan Epoxy Reggie, Epicoat 828), 100 parts by weight of Shin Nippon Rika Co., Ltd., Rigashid MH700, and Sun Apro, 0.5 parts by weight of DBU-phenol salt are mixed. The composition was cured at 150 ° C. for 2 hours, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

Comparative Example 2
Evaluation similar to Example 1 was performed about the commercially available polydimethyl silicone type addition reaction type two-component silicone resin (Toray Dow Corning Silicone Co., Ltd., CY-52276). The results are shown in Table 1.

Comparative Example 3
For 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene (Osaka Gas Chemical Co., Ltd., trade name BPEF-A) used in each example, Nippon Oil & Fats Co., Ltd., Perhexa O was used as a curing agent. 1.0 part by weight was used, and the same evaluation as in Example 1 was performed on the single monomer composition and its cured product. The results are shown in Tables 1 and 2.

  In addition, paracumylphenoxyethyl acrylate (trade name Aronix M110 manufactured by Toagosei Co., Ltd.) used in Examples 1 to 6 and 2- (2-acryloxyethoxy) biphenyl (produced by Toagosei Co., Ltd.) used in Examples 7-11 , Trade name TO1463), and phenoxyethyl acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name Viscoat V192) used in Examples 12 to 13, respectively. The same evaluation as in Example 1 was performed on the single monomer composition and the cured product thereof. The results are shown in Table 2.

Further, for each example, the relationship between the blending weight ratio of monofunctional acrylate to fluorene group-containing acrylate and the refractive index of the resin composition is shown in FIG. The relationship with the glass transition point (Tg) is shown in FIG.

  From Table 1, the cured product of the 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene single monomer composition (Comparative Example 3) has a high refractive index and good light resistance. It can be seen that the viscosity of the composition is high, it cannot be measured in a bowl shape, and the handling property as a sealing resin is poor. Table 2 also shows that the glass transition point is high and the thermal stress relaxation property is poor.

  On the other hand, the cured product of each example has a refractive index of 1.55 or more equivalent to that of the epoxy resin, good light resistance, and the viscosity of the resin composition is in a range suitable as a sealing resin. Further, it can be seen that the glass transition point is lower than that of a single monomer cured product of 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene and is excellent in thermal stress relaxation.

  In particular, from FIG. 2, by setting the blending weight ratio of the monofunctional (meth) acrylate to the fluorene group-containing (meth) acrylate to be 0.5 or more, the glass transition point of the cured product can be made 100 ° C. or less, and FIG. Therefore, in B: paracumylphenoxyethyl acrylate and C: 2- (2-acryloxyethoxy) biphenyl, the resin composition is obtained by setting the blending weight ratio with respect to the fluorene group-containing (meth) acrylate to 0.2-2. It can be seen that the refractive index of can be 1.58 or more.

  Also, from Table 1, when 2- (2-acryloxyethoxy) biphenyl is used as the monofunctional acrylate (Examples 7 to 11), compared to the case of using paracumylphenoxyethyl acrylate (Examples 1 to 6). It can be seen that the cured product has a higher refractive index.

  As for the Shore A hardness, the cured product of each example is lower than the cured product of a single composition of 9,9-bis (4- (2-acryloxyethoxy) phenyl) fluorene, and the hardness of the cured product is low. It can be confirmed that it is reduced.

  Regarding the light extraction efficiency, the light extraction efficiency of Example 1 is 2.24, which is about 10% higher than the light extraction efficiency of Comparative Example 1. According to the present invention, wasteful power consumption is suppressed and heat dissipation is achieved. It can be seen that the amount of emitted light can be increased.

  The cured product of the epoxy resin of Comparative Example 1 has a low light extraction efficiency as compared with each Example, and obvious yellowing is observed in the light resistance test and the heat resistance test. As it turns out, it is not preferable.

  The cured product of the silicone resin of Comparative Example 2 has a low light extraction efficiency of 1.53 times. This is because the refractive index of the silicone resin is low and the cured product of Comparative Example 2 is too soft to maintain a hemispherical shape.

  The resin composition of the present invention is useful as a resin composition for optical sealing of light-emitting elements such as LEDs, optical disks, and lasers, and is particularly useful as a sealing resin composition for high-brightness LEDs.

  In addition, the light-emitting element sealed with the resin composition of the present invention is used in various fields such as a flat panel backlight, a traffic light, lighting of an advertisement billboard, and an automobile headlight.

It is a related figure of the compounding weight ratio with respect to the fluorene group containing acrylate of monofunctional acrylate, and the refractive index of a resin composition. It is a related figure of the compounding weight ratio with respect to the fluorene group containing acrylate of monofunctional acrylate, and the glass transition point (Tg) of hardened | cured material.

Claims (7)

A curable resin composition for optical sealing containing a fluorene group-containing acrylate or methacrylate represented by the following formula (1) and paracumylphenoxyethyl acrylate or 2- (2-acryloxyethoxy) biphenyl .

(Wherein X: — (CH ₂ CH ₂ O) _n − or — (CH ₂ CH ₂ O) _n —CH ₂ CH (OH) CH ₂ O—,
n = 1-5
R: acrylic or methacrylic) The curable resin composition for optical sealing according to claim 1, wherein the refractive index is 1.55 or more. The curable resin composition for optical sealing according to claim 1, wherein the refractive index is 1.58 or more. The glass transition point of hardened | cured material is 100 degrees C or less, The curable resin composition for optical sealing in any one of Claims 1-3. The blending weight ratio of paracumylphenoxyethyl acrylate or 2- (2-acryloxyethoxy) biphenyl to the fluorene group-containing acrylate or methacrylate represented by the formula (1) is 0.2 to 2. The curable resin composition for optical sealing according to any one of the above. An ultrafine particle having a higher refractive index than a mixture of a fluorene group-containing acrylate or methacrylate represented by the formula (1) and paracumylphenoxyethyl acrylate or 2- (2-acryloxyethoxy) biphenyl is dispersed. The curable resin composition for optical sealing according to any one of 1 to 5 . The light emitting element by which LED is sealed using the curable resin composition for optical sealing in any one of Claims 1-6 .

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