JP5248071B2 - Resin composition for optical semiconductor encapsulation - Google Patents

Description

  The present invention relates to a resin composition for sealing an optical semiconductor for sealing an optical semiconductor such as an LED or a photodiode.

  Optical semiconductor sealing materials such as LEDs and photodiodes require high light transmittance. In addition, there is a need for light resistance that does not cause coloration even when exposed to high-energy short-wavelength light such as blue light or violet light for a long time, and heat discoloration that does not cause coloration even when exposed to high temperatures in manufacturing processes such as solder reflow. ing.

  Conventionally, in these applications, an epoxy resin composition using an epoxy resin such as a bisphenol A type epoxy resin and an acid anhydride has been used because of its high transparency and heat resistance. However, since the bisphenol A type epoxy resin has a skeleton derived from bisphenol A in the molecule, the cured product may be colored in the initial stage and the light resistance is poor. As a result, when used for a long time, there is a possibility that the light transmittance may be lowered or discolored.

  On the other hand, as an epoxy resin composition having excellent light resistance, an epoxy resin composition sealing material using an alicyclic epoxy resin and an acid anhydride has been proposed. This sealing material has relatively high performance with respect to light resistance and heat discoloration, but because the refractive index of the cured resin is low, the difference between the refractive index at the emission wavelength of the optical semiconductor material is large, The light extraction efficiency is lowered due to the reflection loss. For example, the brightness of the element is not sufficient for indoor lighting applications.

  In order to solve these problems, a material including a material such as epoxy, silicon, and an acrylic polymer that is substantially transparent to light emitted from the optical semiconductor material, and particles such as a metal oxide dispersed in the material, a metal Particles such as oxide have a refractive index larger than that of the material such as epoxy resin at the emission wavelength of the optical semiconductor material, and particles such as metal oxide have a diameter smaller than the emission wavelength and emit light Light-emitting device that does not substantially absorb light of a wavelength, and a curable epoxy resin composition for encapsulating solid elements, and an epoxy for encapsulating solid elements containing a refractive index regulator such as magnesium oxide, yttria, zirconia, cerium oxide Resin compositions have been proposed (see, for example, Patent Documents 1 and 2).

In these light emitting devices and epoxy resin compositions for sealing solid elements, a compound such as epoxy having a relatively high refractive index is blended with a resin such as epoxy, and the refractive index of the encapsulant is maintained while maintaining transparency. Adjusting is disclosed. However, nano-level particles with an average particle size of several tens of nanometers or less tend to have very high cohesion because of their high surface energy, and even if the primary particle size is sufficiently small, they are sealed by secondary aggregation. It is difficult to maintain the transparency of the material, and in order to maintain the transparency as the sealing material, it is necessary to devise some means to substantially reduce the cohesiveness. Was not made.
JP 2004-15063 A Japanese Patent Laid-Open No. 2004-277797

  In the present invention, fine particles of zirconium oxide are uniformly dispersed in an epoxy resin, have high light transmittance when used as an optical semiconductor sealing material, and have a high refractive index of the cured product. It is an object of the present invention to provide a resin composition for encapsulating an optical semiconductor in which the light extraction efficiency is increased by adjusting the difference from the refractive index at the emission wavelength of the material.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive studies on a resin composition for encapsulating an optical semiconductor, and as a result, the composition contains a resin and zirconium oxide particles, and the average particle of the zirconium oxide particles The present inventors have found a resin composition for encapsulating an optical semiconductor, wherein the particle surface is coated with an organic compound capable of coordination and / or bonding within a diameter range of 1 to 30 nm. Since the zirconium oxide particles are uniformly dispersed in the resin and the average particle diameter is sufficiently small, the composition has high transparency when used as a sealing material. In addition, the encapsulant made of the composition has a high refractive index. Therefore, according to this invention, the said subject can be solved brilliantly.

  Moreover, when the organic compound is an aliphatic carboxylic acid having 6 or more carbon atoms, the dispersibility of the zirconium oxide particles in the resin composition is improved, and the transparency of the sealing material is increased. Further, it is preferable that the surface of the zirconium oxide particles is treated with a silane coupling agent and / or a polyether carboxylic acid because the durability of the sealing material is increased.

  The composition can be cured by adding a curing agent or the like, and the light transmittance of the cured product exceeds 80%, and improves the performance of the optical semiconductor element when used in an optical semiconductor encapsulant. Can be made. In the present invention, the light transmittance refers to the light transmittance when a 2 mm object is irradiated with light having a wavelength of 450 nm.

  The resin composition for sealing an optical semiconductor of the present invention exhibits high light transmittance when used as an optical semiconductor sealing material for sealing an optical semiconductor, and has a high refractive index of the cured product. The light extraction efficiency is increased. Therefore, if the resin composition for encapsulating an optical semiconductor of the present invention is used, an optical element having high luminance can be obtained.

  The resin composition for encapsulating an optical semiconductor of the present invention contains a resin and zirconium oxide particles; the average particle diameter of the zirconium oxide particles is 1 nm or more and 30 nm or less; the surface of the zirconium oxide particles is coordinated and It is characterized by being coated with an organic compound capable of binding.

  The resin according to the present invention is not particularly limited as long as it is usually used as a resin, but is preferably an epoxy resin or a silicone resin, and preferably an epoxy resin.

  The total amount of the resin and the curing agent in the sealing resin composition of the present invention is preferably in the range of 90% by mass to 20% by mass in the composition. When the said compounding quantity exceeds 90 mass%, there exists a possibility that the refractive index of the sealing material obtained from the composition may fall. On the other hand, if the said compounding quantity is less than 20 mass%, there exists a possibility that the viscosity of a composition may become high and workability | operativity may fall. A more preferable upper limit of the total amount of the epoxy resin and the curing agent is 70% by mass, and 50% by mass is most preferable. Moreover, the more preferable lower limit of the blending amount is 30% by mass, and 40% by mass is most preferable.

  As a compounding quantity of the zirconium oxide particle in the resin composition concerning this invention, the inside of the range of 10 mass%-80 mass% in a composition is preferable. If the said compounding quantity is less than 10 mass%, there exists a possibility that the refractive index of the sealing material which consists of a resin composition may become low. On the other hand, when the said compounding quantity exceeds 80 mass%, there exists a possibility that the viscosity of a composition may become high and workability | operativity may fall. The more preferable upper limit of the compounding amount of the zirconium oxide particles is 70% by mass, and 60% by mass is the most preferable. Moreover, the more preferable lower limit of the blending amount is 30% by mass, and 50% by mass is most preferable.

The zirconium oxide particles in the present invention are crystalline zirconium oxide particles and have an average particle diameter in the range of 1 nm or more and 30 nm or less. If the average particle diameter is less than 1 nm, the refractive index of the encapsulant obtained from the resin composition may not be improved, and if the average particle diameter exceeds 30 nm, the transparency of the encapsulant obtained from the resin composition decreases. There is a risk. A more preferable range of the average particle diameter is 5 nm or more and 20 nm or less, 7 nm or more,
More preferably, it is 15 nm or less.

  In the present invention, the average particle diameter may be derived as an average by enlarging with a microscope and measuring the size of each particle. For example, the zirconium oxide particles of the present invention are enlarged and observed with a scanning electron microscope, 100 particles are arbitrarily selected, the length in the major axis direction of each particle is measured, and the average value based on the number is determined as the average particle diameter. It can be.

  The crystal structure of the zirconium oxide particles in the present invention is preferably cubic or tetragonal, and the sealing obtained from the resin composition has 70% or more of the cubic or tetragonal lattice structure of the entire crystal structure. It is preferable because the refractive index of the material can be further improved. The ratio of the cubic or tetragonal lattice structure is more preferably 75% or more, and most preferably 85% or more.

The zirconium oxide particles in the present invention may contain a crystal stabilizing material for crystal stabilization. Examples of the crystal stabilizing material include alkaline earth metal oxides such as MgO and CaO, and rare earth metal oxides such as lanthanide and Y ₂ O ₃ . The content of the crystal stabilizing material is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more.

  In the present invention, the zirconium oxide particles have a surface coated with an organic compound capable of coordination and / or bonding. The coordination and / or bond in the present invention refers to a state in which a hydroxyl group of zirconium oxide and a functional group of an organic compound form a hydrogen bond, a condensed bond, or the like.

  By covering the surface of the zirconium oxide particles with the organic compound, the surface of the zirconium oxide particles, which are inherently hydrophilic, is changed to hydrophobic, and the dispersibility in the resin is improved. Furthermore, nano-level particles having an average particle size in the range of 1 nm or more and 30 nm or less tend to have very high cohesion because of their high surface energy, but the organic compound is coated on the particle surface. Dispersibility in the resin is improved by acting as a protective agent and reducing the cohesiveness between the particles.

  The organic compound capable of coordinating and / or bonding to the surface of the zirconium oxide particles is an organic compound having a functional group capable of coordinating and / or bonding to the zirconia particles, and is coordinated and bonded to the surface of the zirconia particles. Examples of the functional group that can be bonded include a carboxyl group, a hydroxy group, an alkoxyl group, an amine group, a thiol group, an amide group, and the like, and has a strong binding force to zirconia particles and is a sealing material made of a resin composition. A carboxyl group is preferred because of less adverse effects such as discoloration.

  The coordination amount of the organic compound is preferably in the range of 5% by mass to 50% by mass of the entire zirconium oxide particles. If the coordination amount is less than 5% by mass, the dispersibility of the particles in the epoxy resin may be lowered. If the coordination amount exceeds 50% by mass, the content of zirconium oxide in the particles decreases. There is a possibility that the improvement of the refractive index of the sealing material made of the resin composition is reduced. The coordination amount is more preferably within a range of 10% by mass to 40% by mass, and most preferably within a range of 15% by mass to 30% by mass.

  As the organic compound, an aliphatic carboxylic acid having 6 or more carbon atoms is preferable because the dispersibility of particles in the resin is improved. If the aliphatic carboxylic acid has less than 6 carbon atoms, the surface of the zirconium oxide particles cannot be sufficiently hydrophobic, and the dispersibility of the particles in the resin may be reduced.

  Examples of the aliphatic carboxylic acid having 6 or more carbon atoms include hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2-ethylhexanoic acid, 2-methylheptanoic acid, 4-methyloctanoic acid, salicylic acid, naphthenic acid, decane. Examples include acid, undecyl acid, neodecanoic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, and pristanoic acid.

  Zirconium oxide in the present invention may be synthesized by a known method, but a method of obtaining zirconium oxide particles by hydrothermal synthesis in the presence of an organic compound capable of coordinating and / or binding to the surface of zirconium oxide particles, A method of synthesizing a zirconium oxide precursor from an organic compound capable of coordinating and / or bonding to the surface and a zirconium compound, and obtaining zirconium oxide particles by hydrothermal synthesis of the precursor, etc. This is a preferred synthesis method because zirconium oxide particles protected by a compound can be easily obtained.

  When the surface of the zirconium oxide particles in the present invention is treated with a silane coupling agent, the dispersibility of the zirconium oxide particles in the resin is improved, and the water resistance of the sealing material comprising the resin composition of the present invention is improved. And the mechanical strength is further increased. As a method of treating the surface of the zirconium oxide particles with a silane coupling agent, a known method may be used. However, the zirconium oxide particles are dispersed in an arbitrary solvent in advance, and the silane coupling agent is added and heat-treated. A method is mentioned.

  Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltolmethoxysilane, 3- Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyl Diethoxysilane, 3-methacryloxypropyl tolethoxylane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyl trimethoxysilane, hexamethyl disilane disilazane and the like. Among these silane coupling agents, a crosslinking structure is formed with the epoxy resin, and the strength of the sealing material made of the resin composition is increased. Therefore, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Silane coupling agents having a glycidyl group such as glycidoxypropyltolmethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane are preferred.

  The amount of the silane coupling agent relative to the silane coupling agent-treated particles is preferably in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the zirconium oxide particles. If the coordination amount is less than 1 part by mass, the durability of the sealing material made of the resin composition may be reduced. If the coordination amount exceeds 100 parts by mass, the content of zirconium oxide in the particles Therefore, the improvement in the refractive index of the sealing material made of the resin composition may be reduced. The coordination amount is more preferably in the range of 5 to 70 parts by mass, and most preferably in the range of 10 to 40 parts by mass.

  Examples of the method for dispersing the resin and the zirconium oxide particles in the present invention include, for example, a method in which the resin and the zirconium oxide particles are independently synthesized and then mixed together, and a method in which the zirconium oxide particles are synthesized in the resin synthesized in advance. Either method can be adopted. Specifically, for example, two solutions of a solution in which a resin is dissolved and a dispersion in which zirconium oxide particles are uniformly dispersed are uniformly mixed, and the solvent is removed by heating under reduced pressure. A method of mixing particle powder as it is and mixing uniformly, heating and removing the solvent under reduced pressure, a method of mixing a dispersion in which the zirconium oxide particles are uniformly dispersed, mixing uniformly, and removing the solvent by heating under reduced pressure, etc. Is mentioned.

  The resin used in the present invention is not particularly limited as long as it can be used as a matrix resin for a light sealing material, but an epoxy resin or a silicone resin is preferable.

  As an epoxy resin in this invention, what contains 50 mass% or more of saturated cycloaliphatic epoxy resins with respect to the total amount of epoxy resins is preferable. If the blending amount of the saturated cycloaliphatic epoxy resin is less than 50% by mass, the heat discoloration and light resistance of the sealant obtained from the resin composition may be lowered.

  Examples of the saturated cycloaliphatic epoxy resin include 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, bis (3,4-epoxycyclohexyl) adipate, and hydrogenated bisphenol type epoxy resin. , Hydrogenated novolac type epoxy resin, cyclohexanedimethanol diglycidyl ether, ε-caprolactone modified 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, and the like.

  Examples of the epoxy resin other than the saturated cyclic aliphatic epoxy resin in the epoxy resin of the present invention include triglycidyl isocyanurate, butyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. , Trimethylolpropane triglycidyl ether, polyglycidyl ether of dimer acid, and the like.

  In the resin composition of the present invention, when an epoxy resin is used as the resin, it can be cured by adding a curing agent. As the curing agent, an acid anhydride curing agent is preferable because light resistance and heat discoloration are improved.

  The blending amount of the curing agent in the present invention is preferably in the range of 50 to 150 parts by mass with respect to 100 parts by mass of the total amount of epoxy resin. When the compounding quantity of a hardening | curing agent exceeds 150 mass parts, there exists a possibility that the crack resistance of the sealing material obtained from the resin composition may fall. On the other hand, if the said compounding quantity is less than 50 mass parts, the sclerosis | hardenability of a resin composition will become low and there exists a possibility that workability | operativity may fall. A more preferable upper limit of the amount of the curing agent is 120 parts by mass, and 100 parts by mass is most preferable. Moreover, the more preferable lower limit of the blending amount is 70 parts by mass, and 80 parts by mass is most preferable.

  Examples of the acid anhydride used in the acid anhydride-based curing agent include hexahydrophthalic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, pyromellitic anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. An acid etc. are mentioned.

  The resin composition of the present invention preferably contains a curing accelerator in order to accelerate curing and increase productivity.

  Examples of the curing accelerator include triethanolamine, 2,4,6-tris (dimethylaminomethyl) phenol, tertiary amines such as triethylenediamine and dimethylaminoethanol, tertiary amine salts, quaternary ammonium salts, and imidazole compounds. , Diazabicycloalkene compounds, phosphine compounds, quaternary phosphonium salts, boron compounds, organometallic salts, and the like.

  The blending amount of the curing accelerator is preferably in the range of 0.01 to 10 parts by mass and in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin composition of the present invention. Is more preferable.

Examples of the silicone resin of the present invention include organosiloxanes represented by the following formula.
R _p X _q SiO _r
(In the formula, R independently represents an alkyl group, an alkenyl group, an aryl group or an aralkyl group; X independently represents a hydrogen atom, a halogen atom or an OR ′ group (where R ′ represents a hydrogen atom, an alkyl group or an alkenyl group). P + q + 2r = 4; 1 ≦ p + q ≦ 2; 1 ≦ p ≦ 2; 0 ≦ q <2; the above alkyl group or alkenyl group , Aryl group, aralkyl group, alkoxyalkyl group and acyl group may be substituted with at least one group selected from the group consisting of an epoxy group, a glycidyl ether group, an epoxycyclohexyl group and a vinyl group; The terminal group is at least one selected from the group consisting of an epoxy group, a glycidyl ether group, an epoxycyclohexyl group and a vinyl group It may be substituted by a group).

  In the above formula, an alkyl group means a linear or branched aliphatic hydrocarbon having 1 to 20 carbon atoms. For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, lauryl, stearyl and the like. An alkenyl group means a linear or branched aliphatic hydrocarbon having at least one double bond and having 2 to 20 carbon atoms. For example, vinyl, 1-methylvinyl, 1-propenyl, 2-propenyl, 1-methyl-1-propenyl, 2-butenyl, 3-butenyl, 3-methyl-2-butenyl, pentenyl, hexenyl and the like. The aryl group means an aromatic hydrocarbon group, and examples thereof include phenyl, naphthyl, biphenyl and the like. The aralkyl group means the alkyl group substituted with the aryl group, and examples thereof include a benzyl group. Since the alkoxy group means the above alkyl-oxy, examples of the alkoxyalkyl group include methoxymethyl. The acyl group is a remaining atomic group obtained by removing OH of a carboxyl group from carboxylic acid and means a group having 1 to 7 carbon atoms. For example, formyl, acetyl, propionyl, isopropionyl, butyryl, valeryl, pentylcarbonyl, hexylcarbonyl and the like.

  In the above formula, R may be selected according to the characteristics required for the applied device. For example, when UV resistance is required, R is preferably only an alkyl group having 1 to 6 carbon atoms, and when a high refractive index is required, both an alkyl group having 1 to 6 carbon atoms and an aryl group are used. The thing containing is preferable. In the case where both heat resistance and UV resistance are required, R is particularly preferably a methyl group.

  As p, 1 <p ≦ 1.5 is more preferable, and 1.1 ≦ p ≦ 1.3 is more preferable. As q, 0 ≦ q ≦ 1 is more preferable, 0 ≦ q ≦ 0.5 is further preferable, and 0 ≦ q ≦ 0.3 is particularly preferable. As p + q, 1 ≦ p + q ≦ 1.8 is more preferable, 1.1 ≦ p + q ≦ 1.8 is further preferable, and 1.1 ≦ p + q ≦ 1.6 is particularly preferable.

  Further, the degree of polymerization of the silicone resin is not particularly limited, but the weight average molecular weight is preferably 1,000 or more, and more preferably 3,000 or more.

  The silicone resin can also be cured by a conventional method such as addition of a curing agent. For example, when an epoxy group is present in the side chain, it can be suitably cured with an acid anhydride-based curing agent in the same manner as the epoxy resin. Alternatively, when a Si—H structure and a vinyl group are present, they can be cured with a platinum catalyst.

  In order to improve heat resistance, the resin composition of the present invention preferably contains an antioxidant. As the antioxidant, phenolic antioxidants and phosphorus antioxidants can be used. Styrenated phenol, 2,6-di-tbutyl-4-methylphenol, 2,5-di-tbutyl-hydroquinone, 2,2′-methylene-bis (4-methyl-6-tbutylphenol), tris ( Nonylphenyl) phosphite, triphenyl phosphite and the like.

  The blending amount of the antioxidant is preferably within a range of 0.01 to 5 parts by mass, and within a range of 0.1 to 1 parts by mass with respect to 100 parts by mass of the resin composition of the present invention. Is more preferable.

  The resin composition of the present invention may further contain other compounds and auxiliary materials as necessary.

  Examples of the other compounds and auxiliary materials include solvents, ultraviolet absorbers, ultraviolet stabilizers, antistatic agents, color pigments, dyes, plasticizers, elastomers, curing retarders, glass frit, fine glass and silica particles. Can be mentioned.

  The amount of other compounds and auxiliary materials may be in a range that does not impair the effects of the invention, and is preferably in the range of 0.01% by mass to 50% by mass in the resin composition.

  The cured product obtained from the resin composition of the present invention preferably has a light transmittance of more than 80%. When the light transmittance of the cured product is 80% or less, the illuminance of the diode may decrease when the composition is used as a sealing material for a photodiode such as an LED or a photodiode. The light transmittance of the cured product is more preferably 85% or more.

  As a method for measuring the light transmittance of the cured product, a spectrophotometer was applied to a cured product having a thickness of 2 mm prepared by heating and curing at 100 ° C. for 1 hour and 130 ° C. for 2 hours in a predetermined case having an interval of 2 mm. Is used to measure and determine the light transmittance in the thickness direction when irradiated with light having a wavelength of 450 nm.

  The resin composition according to the present invention can be cured by a general curing method after adding the curing agent. For example, a heat curing method, a photocuring method, an electron beam curing method, and the like, and a heat curing method is preferable because a relatively thick seal is possible.

  The cured product according to the present invention can be used as an optical semiconductor sealing material, and the light extraction efficiency is increased. Therefore, the LED for illumination and the LED for automobile headlamp, which are expected to be used in the future, are sealed. It can be effectively used for material applications.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the scope of the present invention is not limited only to these Examples. Unless otherwise specified, “%” indicates “mass%” and “part” indicates “part by mass”.

Synthesis Example 1 Synthesis of zirconium oxide particles (1) 600 parts of tetradecane and 400 parts of neodecanoic acid were mixed to prepare a 40% neodecanoic acid-tetradecane solution. 67.5 parts of magnesium oxide was added to the solution and stirred at 60 ° C. for 1 hour to prepare a magnesium neodecanoate solution. Next, 75 parts of 0.05 mol / L hydrochloric acid aqueous solution was added to 402.8 parts of zirconium oxychloride and dissolved in pure water to 2500 parts to prepare a Zr (IV) aqueous solution. 1125 parts of the Zr (IV) aqueous solution and 800 parts of a magnesium neodecanoate solution were mixed and stirred at 60 ° C. for 40 minutes to prepare a zirconium neodecanoate solution.

  In an autoclave equipped with a stirrer, a mixture of 500 parts of the zirconium neodecanoate solution and 500 parts of water was charged, heated to 175 ° C. in a nitrogen atmosphere, and allowed to react for 3 hours. The pressure at the end of the temperature increase was 0.9 MPa. The reaction solution was taken out, and the reaction product accumulated at the bottom was collected by filtration. The reaction product was washed with acetone, dried, and then dispersed in toluene to obtain a cloudy dispersion. Next, filtration is performed again with a quantitative filter paper (No. 5C, manufactured by Advantech Toyo Co., Ltd.) as a purification step, coarse particles in the dispersion are removed, and toluene in the filtrate is dried by heating under reduced pressure. Zirconium oxide particles (1) as powder were obtained.

  The obtained zirconium oxide particles (1) were magnified and observed with an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation), and 100 particles were arbitrarily selected and the major axis direction of each particle was selected. When the average particle diameter was calculated by measuring the length and calculating the average value, the average particle diameter was 5 nm. Further, when the crystal structure was analyzed by XRD analysis (X-ray powder diffraction analysis), it was a tetragonal crystal structure. Furthermore, absorption derived from C—H and absorption derived from COOH can be confirmed by IR analysis. Zirconium oxide particles (1) are particles coated with neodecanoic acid on the surface, and TG-DTA analysis (thermogravimetric-differential thermal analysis) Confirmed an exothermic peak around 350 ° C., and the amount of neodecanoic acid was 18.6% from the weight loss rate.

Synthesis Example 2 Synthesis of Zirconium Oxide Particles (2) In a dispersion obtained by dispersing 10 parts of the zirconium oxide particles (1) obtained in Synthesis Example 1 in 90 parts of toluene, 2- (3,4-) is used as a silane coupling agent. Epoxycyclohexyl) ethyltrimethoxysilane (trade name: KBM-303, manufactured by Shin-Etsu Chemical Co., Ltd.) (1.5 parts) was added, and the mixture was refluxed at 80 ° C. for 1 hour. 200 parts of acetone was added to the reaction solution, and the aggregated and cloudy particles were separated by filtration, and then dried to obtain zirconium oxide particles (2) subjected to surface treatment with a silane coupling agent. From the IR analysis of the obtained zirconium oxide particles (2), absorption from C—H and absorption from COOH, absorption from Si—O—C, absorption from epoxy groups can be confirmed, and zirconium oxide particles (2 ) Are particles coated on the surface with neodecanoic acid and a silane coupling agent, and the total amount of neodecanoic acid and 3-methacryloxypropyltrimethoxysilane is 25 from the weight loss rate by TG-DTA analysis (thermogravimetric-differential thermal analysis). 0.0%.

Synthesis Example 3 Synthesis of Zirconium Oxide Particles (3) 10-Zirconium oxide particles (1) obtained in Synthesis Example 1 were dispersed in 50 parts of toluene as a polyether carboxylic acid as 2- [2- (2 -Methoxyethoxy) ethoxy] acetic acid (1.5 parts) was added and refluxed at 90 ° C. for 1 hour. 200 parts of acetone was added to the reaction solution, and the aggregated and cloudy particles were separated by filtration, then dried, and zirconium oxide particles (3) surface-treated with polyether carboxylic acid were obtained. When the obtained zirconium oxide particles (3) were subjected to TG-DTA analysis, exothermic peaks were confirmed at around 350 ° C. and around 450 ° C., and the total amount of neodecanoic acid and polyether carboxylic acid was 24.0% from the weight loss rate.

Example 1
Zirconium oxide particles (1) to (3) obtained in Synthesis Examples 1 to 3 are dispersed in toluene, and an epoxy resin, a curing agent, and the like are added to the dispersion in a blending amount shown in Table 1, and uniformly dispersed. Toluene was distilled off under reduced pressure to obtain the optical semiconductor encapsulating resin compositions (1) to (6) of the present invention and comparative encapsulating resin compositions (1) to (3). The obtained composition was put into a case made of a glass plate with a 2 mm spacer in between, and heated at 100 ° C. for 1 hour and 130 ° C. for 2 hours to obtain a cured product having a thickness of 2 mm. The cured product was irradiated with light having a wavelength of 450 nm, and the light transmittance in the thickness direction was measured with a spectrophotometer.

Evaluation Method The optical characteristics in the examples were measured by the following methods.

(1) Refractive index The refractive index of the said hardened | cured material was measured with the Abbe refractometer (Atago Co., Ltd. DR-M2).

(2) Light resistance test About the said hardened | cured material, a super xenon weather meter (made by Suga Test Instruments Co., Ltd.) was used, and a test was performed on the conditions of temperature: 63 degreeC (BPT), humidity: 50% RH, and illumination intensity: 180 W / m < ² >. The light transmittance at a wavelength of 450 nm after 100 hours, 200 hours and 300 hours was measured.

(3) Heat resistance test The cured product was placed in an oven at 150 ° C, and the light transmittance at a wavelength of 450 nm after 72 hours was measured.

  Using the obtained resin compositions for sealing an optical semiconductor (1) to (6) and comparative resin compositions (1) to (3) of the present invention, curing with a thickness of 2 mm was performed in the same manner as described above. A product was prepared, and a refractive index measurement, a light resistance test and a heat resistance test were performed. The results are shown in Tables 1-3.

  As can be seen from the results in Tables 1 to 3, the resin composition of the present invention is a composition excellent in optical properties and durability, and is therefore a composition suitable for an optical semiconductor sealing material. On the other hand, as a comparison, a composition using commercially available zirconium oxide particles having a large average particle diameter has a low light transmittance of a molded product obtained from the composition, resulting in poor transparency. In addition, in the composition using titanium oxide particles, although the refractive index and the light transmittance are high, the light transmittance decreases due to the decomposition of the binder in the light resistance test and heat resistance test, and the durability is inferior. I understood.

Example 2 Silicone Resin Composition Comprising Zirconium Oxide Nanoparticles Coated with Neodecanoic Acid and Synthetic Silane Coupling Agent (1) Synthesis of Zirconium Oxide Particles Sodium hydroxide (80 g, Kishida Chemical Co., Ltd.) at 40 ° C. pure water (640 g) A special grade) was added and dissolved under stirring. Next, neodecanoic acid (396.9 g, manufactured by Japan Epoxy Resin Co., Ltd.) was added with stirring to prepare a sodium neodecanoate aqueous solution. Next, the solution was heated to 80 ° C., and with stirring, zirconium oxychloride (585.99 g, ZrOCl ₂ .8H ₂ O, manufactured by Daiichi Elemental Chemical Co., Ltd., Zircosol ZC-20) was added over 20 minutes. . When stirring was continued at 80 ° C. for 1.5 hours, white and viscous zirconium neodecanoate was produced. After removing the aqueous phase, the zirconium neodecanoate was sufficiently washed with pure water. Next, tetradecane (92 g) was added to the zirconium neodecanoate and stirred.

  Pure water (400 g) was mixed with the obtained zirconium neodecanoate-tetradecane solution. The mixture was charged into an autoclave equipped with a stirrer, and the atmosphere in the reaction vessel was replaced with nitrogen gas. Thereafter, the reaction mixture was heated to 180 ° C. and reacted for 3 hours to synthesize zirconium oxide particles. The pressure in the container when reacted at 180 ° C. was 0.9 MPa. The solution after the reaction was taken out, and the precipitate accumulated at the bottom was filtered off, washed with acetone and dried. When the precipitate (80 g) after drying was dispersed in toluene (800 mL), a cloudy solution was obtained. Next, it filtered again with the quantitative filter paper (Advantech Toyo Co., Ltd. No.5C) as a refinement | purification process, and removed the coarse particle etc. in a deposit. Next, white zirconium oxide nanoparticles were recovered by removing toluene obtained by concentrating the filtrate under reduced pressure.

  When the crystal structure of the zirconium oxide nanoparticles was confirmed with an X-ray diffractometer, diffraction lines attributed to tetragonal and monoclinic crystal structures were detected. From the intensity of the diffraction lines, it was confirmed that the crystal structure was mainly tetragonal and slightly monoclinic. The C value determined from the obtained X-ray diffraction chart was 39.4. Therefore, it was found that the crystallinity of the zirconium oxide nanoparticles was extremely high.

  In addition, the particle diameter of the zirconium oxide nanoparticles was enlarged and observed with an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation), and 100 particles were arbitrarily selected and the long axis of each particle was selected. When the length in the direction was measured and the average value was calculated to determine the average particle size, the average particle size was 5 nm. Furthermore, when analyzed by an infrared absorption spectrum, absorption derived from C—H and absorption derived from COOH were observed. The absorption is considered to be derived from neodecanoic acid covering the zirconium oxide nanoparticles.

  Furthermore, when the mass reduction rate of the zirconium oxide nanoparticles was measured by TG-DTA (thermogravimetric-differential thermal analysis) at a rate of 10 ° C./min in an air atmosphere to 800 ° C., 19 mass% Decrease rate. Therefore, it was confirmed that the neodecanoic acid which coat | covered the zirconium oxide nanoparticle was 19 mass% of the whole particle | grain.

  Further, the particle size distribution is measured, and the conversion coefficient is obtained from the formula: σ / x × 100 [where σ represents the standard deviation of the particle size distribution of the particles and x represents the 50% cumulative diameter (nm) of the particles]. As a result, it was 20%. Therefore, it was found that there was little variation in the particle size of the nanoparticles.

(2) Synthesis of Silane Coupling Agent (Surface Coating Agent A) Before the start of synthesis, methacryloyl group one-end polydimethylsiloxane having a weight average molecular weight of about 5000 (manufactured by Chisso Corporation, Silaplane FM-0721, 160 g), cyclohexyl methacrylate (34 g) and 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503, 6 g) were mixed. Hereinafter, the mixture is referred to as a mixture A. Further, dimethyl-2,2′-azobis (2-methylpropionate) (manufactured by Wako Pure Chemical Industries, V-601, 13.2 g) and toluene (49 g) were mixed. Hereinafter, the mixture is referred to as a mixture B. Furthermore, n-dodecyl mercaptan (12 g) and toluene (40 g) were mixed. Hereinafter, the mixture is referred to as a mixture C.

  Butanol (31.2 g) and toluene (100.4 g) were charged into a 500 mL four-necked flask equipped with a stirrer, thermometer, dripping device, cooling tube and nitrogen blowing tube, and the atmosphere in the flask was replaced with nitrogen. . The solvent was heated with stirring, and when the mixture was refluxed, the entire amount of the mixture A, 52 g of the mixture B, and the entire amount of the mixture C were added dropwise over 2 hours. After the start of dropping, the reaction temperature was maintained at 110 ° C., and the remaining mixture B was added in three portions every hour after the end of dropping. After the entire amount of the mixture B was charged, the mixture was stirred at 110 ° C. for 2 hours. Next, the reaction mixture was cooled to room temperature to obtain a viscous and transparent silane coupling agent. The silane coupling agent is referred to as “surface coating agent A”.

(3) Substitution reaction In a 100 mL four-necked flask equipped with a stirrer, thermometer, cooling tube and nitrogen blowing tube, hexane (43 g), zirconium oxide nanoparticles obtained in the above (1) (4.11 g) ) And the above surface coating agent A (2.87 g). The reaction mixture was stirred at reflux for 8 hours. Next, the reaction mixture was cooled, and the precipitate was filtered off to obtain zirconium oxide nanoparticles (4.31 g) coated with neodecanoic acid and the surface coating agent A.

(4) Silicone resin composition Zirconium oxide nanoparticles (4 g) obtained above were mixed with epoxy group side chain polydimethylsiloxane (manufactured by Toray Dow Corning, SF8411, 5.34 g) to obtain a high-viscosity fluid. A colorless and transparent silicone resin composition was obtained. Therefore, it was found that the zirconium oxide nanoparticles had high dispersibility.

  The resin composition for encapsulating an optical semiconductor according to the present invention has zirconium oxide particles uniformly dispersed in a resin such as an epoxy resin or a silicone resin, and can ensure sufficient transparency when formed into a molded body. The ratio is excellent and the durability is excellent. Therefore, the resin composition for encapsulating an optical semiconductor of the present invention can be effectively used for encapsulating materials for optical diodes such as LEDs and photodiodes.

Claims (5)

Containing epoxy resin and zirconium oxide particles;
The average particle diameter of the zirconium oxide particles is 1 nm or more and 30 nm or less;
The surface of the zirconium oxide particles is coated with an organic compound capable of coordination and / or bonding,
For sealing an optical semiconductor, wherein the organic compound is an aliphatic carboxylic acid having 6 or more carbon atoms, and the surface of the zirconium oxide particles is treated with a silane coupling agent and / or a polyether carboxylic acid. Resin composition. Containing epoxy resin and zirconium oxide particles;
The average particle diameter of the zirconium oxide particles is 1 nm or more and 30 nm or less;
The surface of the zirconium oxide particles is coated with an organic compound capable of coordination and / or bonding,
The organic compound is an aliphatic carboxylic acid having 6 or more carbon atoms,
The coordinating amount of the organic compound is 5% by mass to 50% by mass of the entire zirconium oxide particles.   The resin composition for optical semiconductor encapsulation according to claim 1, wherein the coordination amount of the organic compound covering the surface of the zirconium oxide particles is 5% by mass to 50% by mass with respect to the entire zirconium oxide particles.   The light according to claim 1 or 3, wherein the surface of the zirconium oxide particles is treated with a silane coupling agent, and the silane coupling agent is 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the zirconium oxide particles. Semiconductor sealing resin composition. Are those obtained by curing a composition according to any one of claims 1-4, and an optical semiconductor sealing material whose light transmittance is equal to or greater than 80%.