JP4892380B2 - Reflective material for optical semiconductors - Google Patents

Description

  The present invention relates to a reflective material for an optical semiconductor that generates ultraviolet rays.

  Since the 1990s, the progress of light emitting diodes (LEDs) has been remarkable. Among these, white LEDs are expected as next-generation light sources that replace conventional white light bulbs, halogen lamps, HID lamps, and the like. In fact, LEDs have been evaluated for their features such as long life, power saving, temperature stability, low voltage drive, etc., and are applied to displays, destination display boards, in-vehicle lighting, signal lights, emergency lights, mobile phones, video cameras and the like. Such a light emitting device is usually manufactured by fixing an LED to a concave reflecting material formed by integrally molding a synthetic resin with a lead frame and sealing with a sealing material such as an epoxy resin or a silicone resin.

  In recent years, LEDs that emit ultraviolet light have been used. However, there is no resin material that efficiently reflects ultraviolet rays, and a material having a high reflectance with respect to ultraviolet rays is required. Further, if moisture penetrates into the LED light emitting device, the light emitting element may be damaged by the moisture, and it is desired that water vapor does not enter the device.

As the LED reflector, a resin composition obtained by adding titanium oxide to a polyamide-based resin is often used (see, for example, Patent Document 1). This material has a very high reflectivity in the visible light region. However, since titanium oxide absorbs UV light with a wavelength of 400 nm or less well, this material hardly reflects UV light with a wavelength of 400 nm or less.
A material using potassium titanate fibers instead of titanium oxide is disclosed (for example, see Patent Document 2). Although this material has some improvement in the reflection characteristics against ultraviolet rays, it is still insufficient.

  On the other hand, Patent Document 3 discloses a technique of providing a resin layer (for example, a silicone resin) containing a light reflective filler around a light emitting element when manufacturing an LED light emitting device. As the light reflective filler, a compound containing titanium and oxygen such as titanium oxide and potassium titanate is disclosed. However, since these fillers have the property of absorbing ultraviolet rays, the reflectivity with respect to ultraviolet rays is extremely low. In addition, when silicone resin is used, there are concerns about the problem of low molecular siloxane volatilizing to cause contact failure and the problem of water vapor penetrating into the light emitting device to cause failure of the light emitting element.

Patent Document 4 discloses a light reflecting film in which a surface layer of 10 to 100 μm containing hollow particles is laminated on a polyester resin sheet having a thickness of about 190 μm enclosing air bubbles. This material has a high reflectivity, and it has been shown that the luminance is improved when incorporated in a liquid crystal backlight. However, the melting point of the polyester resin is 253 ° C., and it is melted in the solder reflow process where heat of about 260 ° C. is applied, which is not suitable for manufacturing the LED light emitting device. The size of the LED light emitting device is usually very small, about 5 mm square. The laminate of Patent Document 4 is useful as a large-area sheet-like reflector, but it has been difficult to form a concave shape of about 5 mm and incorporate it into an LED light-emitting device.
JP-A-2-288274 JP 2002-294070 A JP 2000-150969 A JP 2004-101601 A

  An object of the present invention is to provide a reflective material for optical semiconductors which has a high reflectance with respect to ultraviolet rays and hardly transmits water vapor.

According to the present invention, the following reflective materials for optical semiconductors and the like are provided.
1. (A) Polyfunctional (meth) acrylic acid ester containing an acyclic hydrocarbon group having a number average molecular weight of 800 or more, 15 to 80% by mass, and (b) UV transmittance at a wavelength of 350 nm is 50%. Hollow particles made of the above materials: a reflective material for optical semiconductors obtained by polymerizing a heat or photopolymerizable composition containing 20 to 60% by mass.
2. 2. The reflector for an optical semiconductor according to 1, wherein the acyclic hydrocarbon group of (a) has a polyalkadiene structure or a polyalkadiene hydrogenated structure.
3. The reflective material for optical semiconductors according to 1 or 2, wherein the hollow particles are made of a crosslinked resin or an inorganic compound.
4). The reflective material for optical semiconductors according to any one of 1 to 3, wherein the hollow particles are made of a crosslinked styrene resin, a crosslinked acrylic resin, inorganic glass, or silica.
5. Furthermore, the reflecting material for optical semiconductors which contains the base | substrate whose visible light reflectance in wavelength 550nm is 80% or more, and has laminated | stacked the reflecting material for optical semiconductors as described in any one of 1-4 on this base | substrate.
6). The photoelectric conversion element containing the reflecting material for optical semiconductors as described in any one of said 1-5.
7). 7. A photoelectric conversion device comprising the photoelectric conversion element according to 6 above.

  ADVANTAGE OF THE INVENTION According to this invention, it has a high reflectance with respect to an ultraviolet-ray, and can provide the reflecting material for optical semiconductors which is hard to permeate | transmit water vapor | steam.

The optical semiconductor reflective material (LED reflective material) of the present invention can be obtained by polymerizing a heat or photopolymerizable composition containing the following (a) and (b).
(A) 15-80 mass% of polyfunctional (meth) acrylic acid ester containing the acyclic hydrocarbon group of number average molecular weight 800 or more
(B) 20 to 60% by mass of hollow particles made of a material having an ultraviolet transmittance of 50% or more at a wavelength of 350 nm

  The reflective material for LED of the present invention has an extremely high reflectance with respect to ultraviolet rays. Furthermore, since the water vapor permeability is very low, the failure of the light emitting element caused by moisture can be extremely reduced.

Component (a) is a polyfunctional (meth) acrylic ester and contains an acyclic hydrocarbon group having a number average molecular weight of 800 or more. If the number average molecular weight of the acyclic hydrocarbon group is less than 800, the dispersibility of the hollow particles may be deteriorated. The number average molecular weight of the acyclic hydrocarbon group is preferably 1000 to 50000.
In addition, (meth) acrylic acid ester means methacrylic acid ester or acrylic acid ester, and describes both together.
Further, the number average molecular weight of the acyclic hydrocarbon group is a value measured by gel permeation chromatography (GPC), and the number average molecular weight of the polyfunctional (meth) acrylic acid ester is measured. It can be determined by reducing the molecular weight of the acrylic acid moiety.

As the acyclic hydrocarbon group having an average molecular weight of 800 or more in the component (a), for example, polyalkadiene or a hydrogenated product of polyalkadiene is preferable. In particular, a hydrogenated product of polyalkadiene is preferable because of excellent ultraviolet resistance.
Preferable examples of the polyalkadiene include polyisoprene and polybutadiene.
The polyfunctional (meth) acrylic acid ester as the component (a) has two or more (meth) acrylic groups in one molecule. The number of functional groups is preferably 2 or 3. Moreover, a component (a) may be used independently and may use it combining several different things.
Specific examples of the polyfunctional (meth) acrylic acid ester that is component (a) include polybutadiene-terminated diacrylate, hydrogenated polybutadiene-terminated diacrylate, polyisoprene-terminated diacrylate, hydrogenated polyisoprene-terminated diacrylate, and the like.

  In addition, even if it uses a silicone type resin instead of the component (a) mentioned above, the dispersibility of a hollow particle can be improved and also the reflectance with respect to an ultraviolet-ray can be improved. However, the silicone resin is a material having extremely high water vapor permeability and easily takes in moisture that causes a failure of the light emitting element. In contrast, hydrocarbon-based materials have extremely low water vapor permeability and are suitable for optical semiconductor applications.

  The content of the component (a) in the polymerizable composition (excluding additives such as a polymerization initiator) is 15 to 80% by mass, preferably 20 to 80% by mass. If it is less than 15% by mass, the LED light-emitting device may be deformed by heat during manufacture. If it exceeds 80% by mass, the reflectance may be insufficient.

The hollow particles as the component (b) are made of a material having an ultraviolet transmittance of 50% or more at a wavelength of 350 nm. Here, the ultraviolet transmittance means the ultraviolet transmittance for light having a wavelength of 350 nm when the thickness of the material constituting the hollow particles is 250 μm. The ultraviolet transmittance is more preferably 60 to 100%.
Since the ultraviolet rays that have passed through the outer shell of the hollow particles are reflected by the hollow portion, a material having a high ultraviolet transmittance is required. In order to increase the reflectance at the hollow portion, it is preferable that the difference in refractive index between the portion constituting the hollow particle and the gas existing inside the hollow particle is large. The gas present inside the hollow particles is usually air, but may be an inert gas such as nitrogen or argon, or may be a vacuum.

  The hollow particles are preferably particles that contain one or more closed cells inside the particles, but may be secondary particles in which hollow portions are formed. The material constituting the hollow particles may be an organic compound or an inorganic compound. However, when light is absorbed by the outer shell of the hollow particles, the ultraviolet rays that reach the inside of the hollow particles are reduced, and the reflectance at the hollow portion is reduced. Therefore, those that do not absorb much ultraviolet rays are preferable. Moreover, since a hollow part is destroyed by heat processing and a reflective characteristic will be lost when a hollow part is lose | eliminated, a thing with high heat resistance is preferable.

As such materials, for inorganic compounds, inorganic glass, metal oxides such as silica and alumina, and metal salts such as calcium carbonate, barium carbonate, calcium silicate, and nickel carbonate can be suitably used.
In the organic compound, a polystyrene-based resin, a poly (meth) acrylate-based resin, a cross-linked product thereof, and the like can be suitably used, and one or more of these may be included. Among these, inorganic glass, silica, a crosslinked (meth) acrylic resin, and a crosslinked styrene resin are preferable.

  The outer diameter of the hollow particles is not particularly limited. From the viewpoint of light reflectivity and handleability, 0.01 to 500 μm is preferable. If it is smaller than 0.01 μm, the hollow particles may be dispersed unevenly. If it is larger than 500 μm, the surface of the reflector is roughened, and the reflectance is lowered. The inner diameter of the hollow particles is not particularly limited. From a light reflective viewpoint, 0.005-100 micrometers is preferable and 0.1-50 micrometers is more preferable. Outside this range, the reflection efficiency deteriorates.

  The content of the hollow particles in the polymerizable composition (excluding additives such as a polymerization initiator) is 20 to 60% by mass, preferably 25 to 55% by mass. If it is less than 20% by mass, the reflectance may be lowered. If it exceeds 60% by mass, the dispersibility of the hollow particles may deteriorate.

You may add (meth) acrylic acid ester other than a component (a) to the heat | fever or photopolymerizable composition used by this invention. In this case, the ratio of the total amount of component (a) and other (meth) acrylic acid ester in the polymerizable composition (excluding additives such as a polymerization initiator) is preferably 40 to 80% by mass.
Examples of (meth) acrylic acid esters include methyl acrylate, fluoromethyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2,2,2-trifluoroethyl acrylate, 2-hydroxyethyl acrylate, 1, 2,2,2-tetrachloroethyl acrylate, propyl acrylate, isopropyl acrylate, 2-chloro-1- (chlorodifluoromethyl) ethyl acrylate, 1,2,2,2-tetrafluoro-1- (trifluoromethyl) ethyl acrylate 2,2,2-trifluoro-1- (trifluoromethyl) ethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 1-methylethyl acrylate, 2- (methyl Thio) ethyl acrylate, 2-methoxyethyl acrylate, 2-hydroxypropyl acrylate, 2-propenyl acrylate, 1-ethoxy-2,2,2-trifluoroethyl acrylate, 2- (ethylthio) ethyl acrylate, 2-ethoxyethyl acrylate 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 3- (methylthio) propyl acrylate, 1-methylpropyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate 4-oxapentyl acrylate, 2- (trifluoroethoxy) ethyl acrylate, 2- (1,1,2,2-tetrafluoroethoxy) ethyl acrylate, 3- (ethylthio) propyl acrylate, 1-ethylpropyl acrylate, 2 , , 3,3,4,4,5,5-octafluoropentyl acrylate, 2,2-dimethylpropyl acrylate, 2,2,3,3,4,4,5,5,5-nonafluoropentyl acrylate, 4, -Methylthiobutyl acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, 4-oxahexyl acrylate, 3-methoxybutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylbutyl acrylate, 2-methylpentyl acrylate, 4-methyl -2-pentyl acrylate, phenyl acrylate, 2-chlorophenyl acrylate, 4-chlorophenyl acrylate, 2,4-dichlorophenyl acrylate, pentachloroacrylate, 3,3,4,4,5,5,6,6,6- Ndecafluoroacrylate, pentafluoroacrylate, heptyl acrylate, phenylmethyl acrylate, 2-methylphenyl acrylate, 3-methylphenyl acrylate, 4-methylphenyl acrylate, 1-methylhexyl acrylate, 4-methoxyphenyl acrylate, octyl acrylate, Acrylic esters such as 2-phenylethyl acrylate, 1-methylheptyl acrylate, nonyl acrylate, decyl acrylate, methyl methacrylate, ethyl methacrylate, 2-chloroethyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-nitro Ethyl methacrylate, 2-hydroxyethyl methacrylate, propyl methacrylate, isopropyl methacrylate, 2-meth Cyethyl methacrylate, allyl methacrylate, glycidyl methacrylate, 2-chloropropyl methacrylate, trimethylsilyl methacrylate, 2,2,2-trifluoro-1-methylethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, heptafluoroisopropyl Methacrylate, hexafluoroisopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, 2-ethoxyethyl methacrylate, diethylene glycol methacrylate, nonafluoro-tert-butyl methacrylate, 2,2,3,3,4,4 , 4-Heptafluorobutyl methacrylate, pentyl methacrylate, cyclopentyl methacrylate Chlorate, 2,2-diethylpropyl methacrylate, 1-methylbutyl methacrylate, isoamyl methacrylate, 2,2,3,3,4,4,5,6-octafluoropentyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, 3 , 3-dimethylbutyl methacrylate, 2-ethylbutyl methacrylate, 1-methylcyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, 3-methylcyclohexyl methacrylate, 4-methylcyclohexyl methacrylate, 1,1-diethylpropyl methacrylate, 2-methylphenyl methacrylate , 3-methylphenyl methacrylate, 4-methylphenyl methacrylate, benzyl methacrylate, 2-methoxy Phenyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, 2-phenylethyl methacrylate, 2,4- Examples thereof include methacrylic acid esters such as dimethylphenyl methacrylate, 2,5-dimethylphenyl methacrylate, 2,6-dimethylphenyl methacrylate, 3,5-dimethylphenyl methacrylate, nonyl methacrylate, decyl methacrylate, and isodecyl methacrylate.
Of these, (meth) acrylic acid esters containing no aromatic ring are preferred.

  60 mass% or less of a composition is preferable, and, as for the addition amount of (meth) acrylic acid ester other than a component (a), More preferably, it is 50 mass% or less. If it exceeds 60% by mass, the dispersibility of the hollow particles may deteriorate.

In the heat or photopolymerizable composition used in the present invention, known antioxidants and light stabilizers can be used as additives.
Antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, lactone antioxidants, amine antioxidants, and the like. The use amount of these additives is usually 0.005 to 5 parts by mass, preferably 0.02 to 2 parts by mass, with respect to 100 parts by mass of the total amount of the polymerizable components. Two or more of these additives may be combined.

  As the light stabilizer, a hindered amine light stabilizer can be suitably used. The addition amount is usually 0.005 to 5 parts by mass, preferably 0.02 to 2 parts by mass with respect to 100 parts by mass of the total amount of the polymerizable components. Two or more of these additives may be combined.

The reflective material of the present invention can be produced by mixing the component (a) with the component (b) hollow particles, and then polymerizing and curing with heat or light. In order to accelerate the polymerization reaction, a polymerization initiator may be added. The polymerization initiator is not particularly limited. For example, a radical polymerization initiator can be used. Examples of radical polymerization initiators include ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide , Hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide, diisobutyryl peroxide, bis-3,5,5-trimethylhexanol peroxide, lauroyl peroxide, benzoyl peroxide, m-toluylbenzoyl peroxide Diacyl peroxides such as oxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane Dialkyl such as 1,3-bis (t-butylperoxyisopropyl) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexene Peroxides, 1,1-di (t-butylperoxy-3,5,5-trimethyl) cyclohexane, 1,1-di-t-butylperoxycyclohexane, 2,2-di (t-butylperoxy) butane, etc. Peroxyketals, 1,1,3,3-tetramethylbutylperoxyneodicarbonate, α-cumylperoxyneodicarbonate, t-butylperoxyneodicarbonate, t-hexylperoxypivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, di-t-butylperoxyhexahydroterephthalate, 1,1,3 3-tetramethylbutylperoxy-3,5,5-trimethylhexanoate, t-amylperoxy3,5,5-trimethylhexanoate, t-butylperoxy3,5,5-trimethylhexanoate, t-butyl Alkyl peresters such as peroxyacetate, t-butylperoxybenzoate, dibutylperoxytrimethyladipate, di-3-methoxybutylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, bis (1,1-butylcyclohexaoxydi) -Bonate), diisopropyloxydicarbonate, t-amylperoxyisopropylcarbonate, t-butylperoxyisopropylcarbonate, t-butylperoxy-2-ethylhexylcarbonate, 1,6-bis (t-butylperoxycarboxy) hexane, and other peroxycarbonates And the like. Moreover, perhexa 3M-95 (Nippon Yushi Co., Ltd.), azobisisobutyronitrile, etc. are mentioned.
The usage-amount for a radical polymerization initiator is 0.01-5 mass parts normally with respect to 100 mass parts of said heat | fever or photopolymerizable compounds whole quantity, Preferably it is 0.05-1.0 mass part. The above radical polymerization initiators may be used alone or in combination.

  In the present invention, the polymerizable composition is preferably formed into a reflector simultaneously with polymerization. “Molding into the shape of a reflector simultaneously with polymerization” means, for example, obtaining a molded body only by an operation of curing the polymerizable composition on a substrate. For example, the liquid polymerizable composition is covered with a coating or spin coating, and then the polymerization is completed by energy such as light or heat to form a molded body. In the case where a polymer of the polymerizable composition is prepared in advance and then molded, for example, (1) the polymer of the polymerizable composition is dissolved in a solvent or the like, applied to a support or the like, and dried to form a reflector, (2) When the polymer of the polymerizable composition is used as a reflector by injection molding or extrusion molding, the following problems may occur.

When the reflective layer 24 as shown in FIG. 1B to be described later is formed by the method (1), for example, it is necessary to fill the concave portion of the resin composition substrate 10 with a polymer solution of the polymerizable composition. is there. In this case, after the solvent is volatilized, not only the reflective layer 24 is formed, but also the surface of the light emitting element 20 is covered with the white reflective layer, and light cannot be extracted from the light emitting element 20.
Moreover, if the polymer is once melted and then shaped as in the method (2), it can be formed into a concave shape. However, in order to melt the polymer, it must be exposed to a fairly high temperature for several minutes. During this time, the polymer is deteriorated and colored, so that a decrease in reflectance is inevitable.
As in the present invention, the ideal reflective layer can be formed only by applying the polymerizable composition to the concave portion of the resin composition substrate 10 and polymerizing it at the same time as forming the reflective material.

  When the reflective material of the present invention is formed into a layer, the thickness of the layer is preferably 0.05 to 2 mm, and more preferably 0.25 to 2 mm. In order to make the light emitting device smaller, it is preferable that the reflective layer is thin. However, the thicker the reflective layer, the higher the probability that light will collide with the hollow particles.

The above-mentioned reflecting material is preferably used in a state where the reflecting material is laminated on a substrate made of a material having a high visible light reflectance. This makes it possible to obtain a high reflectance not only with ultraviolet rays but also with visible light. Here, “a material having a high reflectance for visible light” means a material having a visible light reflectance of 80% or more at a wavelength of 550 nm.
As a material for such a substrate, a resin composition containing a solid particle white pigment can be mentioned. A substrate made of a resin composition containing a solid particle white pigment such as titanium oxide has a low ultraviolet reflectivity but a very high visible light reflectivity.
When the reflective material of the present invention is laminated on a substrate made of this resin composition, when visible light is irradiated from above the laminated body, the transmitted light is reflected by the substrate without being reflected by the reflective material layer. Therefore, by laminating as described above, a high reflectance can be obtained not only for ultraviolet rays but also for visible light.

  Examples of the solid particle white pigment include titanium oxide, silica, potassium titanate, barium sulfate, alumina, zinc oxide, calcium carbonate, talc, and mica.

  Although content in particular of a solid particle type white pigment is not restrict | limited, 1-50 mass% is preferable with respect to the resin composition containing a solid particle type white pigment, and 5-40 mass% is more preferable.

  Examples of the resin containing the solid particle white pigment include polyamide resin, liquid crystal polymer, polyether resin, syndiotactic polystyrene, and polyester resin.

The content of the resin containing the solid particle white pigment is not particularly limited, but is preferably 40 to 95 mass%, more preferably 50 to 90 mass% with respect to the resin composition containing the solid particle white pigment.
In addition, the resin composition containing the solid particle-based white pigment can contain glass fiber or the like.

  Moreover, it is also preferable to use the metal which consists of 1 type, or 2 or more types chosen from aluminum, gold | metal | money, silver, copper, nickel, or palladium for a base | substrate. Even with such a metal substrate, it is possible to obtain a high reflectance with ultraviolet rays and visible light. However, since the reflectance varies depending on the surface state of the metal, it is important to select a metal in a highly reflective surface state.

The shape of the substrate does not necessarily have to be a flat surface, and may be an arbitrary shape. For example, it may be formed into a concave shape as shown in FIG.
FIG. 1 is a diagram showing an example of a reflector for LED. In this example, a resin composition containing a solid particle-based white pigment is molded integrally with the lead frame 12 to form a resin composition substrate 10 having a recess (FIG. 1a), and the polymerizable composition described above is formed on the inner wall of the recess of the substrate 10. Is applied and cured to form the reflective layer 24 (FIG. 1b). Further, a silicone resin is applied on the reflective layer 24 and cured to form the sealing layer 30 (FIG. 1c).
The thickness of the reflective layer 24 may vary depending on the location (see FIG. 1B). The maximum thickness of this layer is preferably 0.05 to 3 mm, more preferably 0.25 to 2 mm. The outer diameter and height of the base are both as small as about 5 mm.

The materials used in the examples and comparative examples are as follows.
[Materials used]
(A) Component (a): Multifunctional (meth) acrylic acid ester (1) Hydrogenated polybutadiene-terminated diacrylate 30: Osaka Organic Chemical Industry Co., Ltd., SPBDA-S30, number average molecular weight = 2000 to 3000 (catalog value) )
(2) Hydrogenated polybutadiene-terminated diacrylate 50: manufactured by Osaka Organic Chemical Industry Co., Ltd., SPBDA-S50, number average molecular weight = 3000 to 4000 (catalog value)
(3) Polybutadiene-terminated diacrylate: Osaka Organic Chemical Industry Co., Ltd., BAC-45, number average molecular weight = about 3000 (catalog value)

(B) Component (b): Hollow particles Hollow silica beads: HSC-110C (Potters Ballotini Co., Ltd., average particle diameter 13 μm, average pore diameter 9 μm, glass UV transmittance 90% (wavelength 350 nm, thickness 250 μm))

(C) (meth) acrylic acid esters other than component (a) (1) Stearyl methacrylate: Acryester S manufactured by Mitsubishi Rayon Co., Ltd.
(2) Polyethylene glycol # 400 dimethacrylate: manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester 9G
(3) 1,9-nonanediol diacrylate: Osaka Organic Chemical Industry Co., Ltd., V # 260, molecular weight = 268

(D) Radical polymerization initiator Perhexa HC: manufactured by NOF Corporation

(E) Silicone resin (used in comparative examples)
(1) Silicone resin a: manufactured by Shin-Etsu Chemical Co., Ltd., KER2500a
(2) Silicone resin b: manufactured by Shin-Etsu Chemical Co., Ltd., KER2500b

Examples 1-8, Comparative Examples 1-4
(Meth) acrylic acid ester and hollow particles were blended in the proportions shown in Table 1, and 0.1 parts by mass of perhexa HC was added to 100 parts by mass of the polymerization component and stirred well to obtain a thermopolymerizable composition. .
In addition, the dispersibility of the hollow particles in this composition was evaluated by the following evaluation (1).

Next, after sufficiently stirring the thermopolymerizable composition, it was coated on a 300 μm thick aluminum plate (reflectance with respect to light having a wavelength of 550 nm = 13.6%, reflectance with respect to light having a wavelength of 380 nm = 18.5%). And heated at 110 ° C. for 3 hours and 160 ° C. for 1 hour to obtain a cured product having a thickness of about 500 μm.
The reflectance of the obtained sample was measured according to the following evaluation (2). However, in the cured product obtained in Comparative Example 2, the hollow particles were clearly dispersed in the mottle, and a uniform product could not be formed. Therefore, no further evaluation was performed.
Moreover, heat processing was performed by the method shown to following evaluation (3), and heat resistance was evaluated. Furthermore, the water vapor transmission rate was measured by the following evaluation (4) for a sample obtained by polymerizing a composition to which no hollow particles were added in the formulation of each example.

(1) Dispersibility of hollow particles in the composition 5 g of the thermopolymerizable composition was weighed into an 8 ml screw tube, stirred vigorously, and after confirming that the hollow particles were sufficiently dispersed, placed on a flat desk. Left to stand. After 5 hours, the dispersibility of the hollow particles was visually evaluated.

(2) Reflectivity of cured product Shimadzu Corp., self-recording spectrophotometer UV-2400PC, Shimadzu Corp. multi-purpose large sample chamber unit MPC-2200 type is attached, and reflectance at a wavelength of 380 nm ( %). Incidentally, barium sulfate was used as a reference.

(3) Heat-resistant deformation property It heat-processed by letting a sample pass through the inside of a solder reflow furnace (the product made from TAMURA Corporation, TAS20-15N). The surface appearances before and after the heat treatment were compared by microscopic observation, and the presence or absence of deformation during the heat treatment was judged. The heat treatment conditions for the sample in the solder reflow furnace were as follows.
150 ° C. for 60 seconds → (temperature increase rate 200 ° C./min)→260° C. for 5 seconds → (temperature decrease rate 200 ° C./min)→150° C. → (air cooling)

(4) Water vapor transmission rate It implemented based on JISZ0208. The sample size was 100 mm × 150 mm × 0.5 mm.
For the measurement, a sample prepared by the following method was used. That is, only the acrylic ester of the (meth) components (A) and (C) is blended in the ratio shown in the table, 1000 ppm of perhexa HC is added, and the well-stirred thermopolymerizable composition is 100 mm × 150 mm × 0.5 mm. And was cured under conditions of 110 ° C. for 3 hours and 160 ° C. for 1 hour.
The evaluation results are shown in Tables 1 and 2.

Example 9
The thermopolymerizable composition prepared in Example 2 was applied on a 300 μm thick aluminum plate and cured (110 ° C. for 3 hours, 160 ° C. for 1 hour) to obtain a cured product having a thickness of about 300 μm. When the reflectance was measured, it was 79.5% at a wavelength of 380 nm.

Example 10
The thermopolymerizable composition prepared in Example 2 was applied onto a 300 μm thick aluminum plate and cured (110 ° C. for 3 hours, 160 ° C. for 1 hour) to obtain a cured product having a thickness of about 150 μm. When the reflectance was measured, it was 74.6% at a wavelength of 380 nm.

Example 11
Polyphthalamide plate [manufactured by Yuko Shokai Co., Ltd., highly visible light reflective substrate: raw material, Amodel A4122NLWH905, 2 mm × 25 mm × 100 mm: reflectivity for light of wavelength 550 nm = 90.4%, reflectivity for light of wavelength 380 nm = 12.5%], the thermopolymerizable composition prepared in Example 2 was applied and cured (110 ° C. for 3 hours, 160 ° C. for 1 hour) to form a 500 nm reflective layer. did.
The reflectance of this laminate was 91.3% at 550 nm and 79.0% at 380 nm. On the other hand, the reflectance when the same thermopolymerizable composition was applied and cured on an aluminum plate was 84.9% at 550 nm and 81.5% at 380 nm.

Comparative Example 5
Silicone resin a, silicone resin b, and hollow particles (HSC110C) were mixed at a ratio of 30:30:40 (mass%) and stirred well to obtain a thermopolymerizable composition. The dispersibility of the hollow particles in this composition was evaluated according to the above method (1).
Next, after sufficiently stirring this thermopolymerizable composition, it was applied on the same 300 μm-thick aluminum plate as in Example 1, heated at 100 ° C. for 1 hour and at 150 ° C. for 5 hours, and cured to a thickness of about 500 μm I got a thing.
The reflectance of the sample thus obtained was evaluated according to the evaluation methods (2) to (4). The evaluation results are shown in Table 2.

  The reflective material of the present invention can be used for lamp reflectors for liquid crystal displays, reflectors for showcases, reflectors for illumination, LED reflectors, and the like. As the photoelectric conversion device including the reflective material of the present invention and the photoelectric conversion device including the photoelectric conversion device, specifically, various displays, destination display boards, in-vehicle illumination, signal lights, emergency lights, mobile phones, video cameras, etc. Examples include OA equipment, electrical and electronic equipment and parts, and automobile parts.

It is a figure which shows an example of the reflector for LED, (a) is sectional drawing of the molded object obtained by injection-molding a resin composition, (b) attaches LED to the molded object of (a), It is sectional drawing when the polymeric compound containing a hollow particle is apply | coated and polymerized inside a molded object, (c) is sectional drawing when a sealing agent is injected into the recessed part of (b), and it hardens | cures.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resin composition base | substrate 12 Lead frame 20 Light emitting element 22 Wire bonding 24 Reflective layer (reflective material)
30 Sealing material

Claims (7)

(A) polyfunctional (meth) acrylic acid ester containing an acyclic hydrocarbon group having a number average molecular weight of 800 or more: 15 to 80% by mass, and
(B) A hollow particle made of a material having an ultraviolet transmittance of 50% or more at a wavelength of 350 nm: a reflective material for an optical semiconductor obtained by polymerizing a heat or photopolymerizable composition containing 20 to 60% by mass.   The reflective material for optical semiconductors according to claim 1, wherein the acyclic hydrocarbon group of (a) has a polyalkadiene structure or a polyalkadiene hydrogenated structure.   The optical semiconductor reflective material according to claim 1, wherein the hollow particles are made of a crosslinked resin or an inorganic compound.   The said hollow particle consists of crosslinked styrene resin, crosslinked acrylic resin, inorganic glass, or silica, The reflecting material for optical semiconductors as described in any one of Claims 1-3.   Furthermore, the reflection for optical semiconductors which contains the base | substrate whose visible light reflectance in wavelength 550nm is 80% or more, and has laminated | stacked the reflection material for optical semiconductors as described in any one of Claims 1-4 on this base | substrate. Wood.   The photoelectric conversion element containing the reflecting material for optical semiconductors as described in any one of Claims 1-5.   A photoelectric conversion device comprising the photoelectric conversion element according to claim 6.

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