JP2012193238A - Urethane resin composition, optical adhesive, optical molded article and optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urethane resin composition which can form a cured product having both sufficiently high light transmissivity and low stress.SOLUTION: The two-part type urethane resin composition comprises a liquid A containing a polyol component and inorganic oxide particles, and a liquid B containing a polyisocyanate component. The polyol component contains a tri- or more-functional polyol having a hydroxyl group value of 550-900 mgKOH/g. The polyisocyanate component contains an alicyclic polyisocyanate compound having an alicyclic group and two or three isocyanate groups, wherein at least one isocyanate group is bound to the secondary carbon constituting the alicyclic group. The difference between the refractive index of a cured product obtained by mixing the inorganic oxide particle-free liquid of the liquid A with the liquid B and curing, and the refractive index of the inorganic oxide particles at a wavelength of 589.3 nm is ≤0.02.

Description

  The present invention relates to a urethane resin composition, an optical adhesive using the same, an optical molded body, and an optical semiconductor device.

  In the optical semiconductor device, the sealing member is molded by curing the resin composition in order to protect the optical semiconductor element. The resin composition is usually cured and molded by a potting method in which the resin composition is cast in a case or in a lead frame cavity, or in a liquid transfer molding in which the resin composition is filled in a cavity formed by a molding die in a molding apparatus. Or compression molding method. At this time, a hard transparent resin is required in a structure in which the shape of the optical semiconductor device is formed only by the transparent resin and the lead frame, or in a structure in which the lens shape is formed by the transparent resin.

  As a sealing member of the optical semiconductor device, an epoxy resin, a silicone resin, a polyester resin, a urethane resin, or the like is used. For example, Patent Document 1 discloses a urethane resin for a photoelectric conversion element sealing material.

JP 2001-278951 A

  On the other hand, in a sealing member for sealing an optical semiconductor element and an optical adhesive for bonding an optical element, stress is generated due to a difference in thermal expansion coefficient between different materials included in the applied structure, for example, an optical element and a lead frame. It may occur and peel off, reducing the reliability of the optical semiconductor device. Thus, a method has been proposed in which an inorganic filler is filled into a resin composition to lower the thermal expansion coefficient and reduce the stress.

However, silica generally used as an inorganic filler has a refractive index lower than that of a resin, and therefore, light transmittance tends to decrease according to the amount of filling. Further, when an epoxy resin is used as the sealing member and an oxide filler containing boron oxide (B ₂ O ₃ ) is used as the inorganic filler, boron ions are eluted in the epoxy resin composition, and light transmittance is achieved. And mechanical strength may be reduced.

  The present invention has been made in view of the above circumstances, and a urethane resin composition capable of forming a cured product having both sufficiently high light transmittance and low stress, an optical adhesive using the same, and optical molding It is an object to provide a body and an optical semiconductor device.

  The present invention is a two-component urethane resin composition comprising a liquid A containing a polyol component and inorganic oxide particles and a liquid B containing a polyisocyanate component, and the polyol component has a hydroxyl value of 550 to 900 mgKOH / g. The polyisocyanate component has an alicyclic group and two or three isocyanate groups, and at least one isocyanate group is a secondary carbon constituting the alicyclic group. The refractive index of the cured product obtained by curing by mixing the liquid B and the liquid obtained by removing the inorganic oxide particles from the liquid A at a wavelength of 589.3 nm, which contains an alicyclic polyisocyanate compound bonded to A two-component urethane resin composition having a difference from the refractive index of inorganic oxide particles of 0.02 or less is provided.

  The two-component urethane resin composition of the present invention can form a cured product having both sufficiently high light transmittance and low stress, and adheres a sealing member or an optical element for sealing an optical semiconductor element. Useful as an optical adhesive.

  When the refractive index at a wavelength of 589.3 nm of the cured product and the inorganic oxide particles is 1.52 or less, the light transmittance of the cured product obtained by curing the urethane resin composition can be further improved. .

The inorganic oxide particles contain silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and calcium oxide (CaO), thereby reducing the linear expansion coefficient of the cured product of the urethane resin composition. , The stress can be further reduced.

  Furthermore, from the viewpoint of maintaining a good balance between light transmittance and low stress property of the cured product of the urethane resin composition, the content of the inorganic oxide particles is 30% by mass based on the total amount of the liquid A and the liquid B. The following is preferable.

  The present invention also provides an optical adhesive containing the two-component urethane resin composition of the present invention, and an optical molded body obtained by curing the two-component urethane resin composition. The present invention further provides an optical semiconductor device comprising a sealing member made of a cured product obtained by curing the two-component urethane resin composition.

  According to the present invention, there are provided a urethane resin composition capable of forming a cured product having both sufficiently high light transmittance and low stress, an optical adhesive, an optical molded body, and an optical semiconductor device using the same. be able to.

It is sectional drawing which shows one Embodiment of an optical semiconductor device. It is sectional drawing which shows one Embodiment of an optical semiconductor device.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  The urethane resin composition of this embodiment is a two-component urethane resin composition comprising a liquid A containing a polyol component and inorganic oxide particles and a liquid B containing a polyisocyanate component, and the polyol component has a hydroxyl value. The polyisocyanate component has an alicyclic group and two or three isocyanate groups, and at least one isocyanate group has an alicyclic group. It contains an alicyclic polyisocyanate compound bonded to the secondary carbon, and is obtained by curing by mixing a liquid obtained by removing inorganic oxide particles from liquid A at a wavelength of 589.3 nm and liquid B. The difference between the refractive index of the cured product and the refractive index of the inorganic oxide particles is 0.02 or less. Note that 589.3 nm is a wavelength of a sodium lamp, and is generally a wavelength used for measuring the refractive index of an optical material. Moreover, it is a wavelength close | similar to the light source of the optical semiconductor device to which this resin composition is applied.

(Polyol component)
The polyol component which concerns on this invention contains the compound which has 3 or more alcoholic hydroxyl groups, and the hydroxyl value is 550-900 mgKOH / g.

  The polyol component having such a hydroxyl value is excellent in compatibility with the polyisocyanate component, and a cured product having a uniform glass transition temperature can be obtained. If the hydroxyl value of the polyol compound is greater than 900 mg KOH / g, the compatibility with the polyisocyanate component tends to decrease, and if it is less than 550 mg KOH / g, the compatibility with the polyisocyanate component is obtained, but the glass transition temperature of the cured product is obtained. (Hereinafter referred to as “Tg” in some cases) tends to decrease.

  The hydroxyl value of the polyol compound is determined by adding the polyol compound to a pyridine solution containing acetic anhydride as an acetylating reagent, acetylating the hydroxyl group, then decomposing excess acetylating reagent with water, and It can be determined by titrating with potassium oxide.

  In this specification, “excellent compatibility” means that a transparent and uniform resin composition is obtained when a polyol component and a polyisocyanate component are mixed at room temperature. The “cured product having a high glass transition temperature” means a cured product having a Tg of 100 ° C. or higher.

  As the polyol compound, for example, aliphatic polyol, alicyclic polyol, polyether polyol, polycarbonate polyol, polyester polyol, polycaprolactone polyol, and acrylic resin polyol can be used. Since the refractive index of the cured product of the urethane resin composition can be easily adjusted to 1.52 or less, the polyol compound is preferably an aliphatic polyol having a short chain length, specifically, trimethylol. A compound obtained by adding 1 to 3 moles of propylene oxide or ethylene oxide to 1 mole of propane is preferable.

  While trimethylolpropane is solid, a compound obtained by adding propylene oxide or ethylene oxide to trimethylolpropane is liquid and easy to handle. Furthermore, in the case of a compound obtained by adding propylene oxide to trimethylolpropane, the Tg of the cured product can be further increased as compared with a compound obtained by adding ethylene oxide due to steric hindrance of the methyl group.

  When an addition reaction of 1 to 3 moles of propylene oxide or ethylene oxide is performed with respect to 1 mole of trimethylolpropane, 1 mole addition product of raw material trimethylolpropane, propylene oxide or ethylene oxide is included in the reaction product. A mixture of a plurality of polyol compounds such as a 2 mol addition product, a 3 mol addition product, and a 4 mol addition product is obtained. The polyol compound may be a mixture thereof, and in this case, the hydroxyl value is a value calculated from the mixture.

  The polyol compound may be used alone, but other polyols can be used in combination in order to adjust the crosslinking density and viscosity. In that case, the content of the other polyol compound is preferably 20% by mass or less based on the total amount of the polyol component. By setting it in such a range, even when several kinds of polyols are used in combination, it is possible to prevent non-uniformity of the cured product of the urethane resin composition caused by a difference in reactivity between the polyol compounds.

  The polyol component may contain a hydroxyl group residual prepolymer. By including the hydroxyl group residual prepolymer in the polyol component, the compatibility between the polyol component and the polyisocyanate component can be further improved. The hydroxyl group-remaining prepolymer is obtained by reacting the polyol component with a polyisocyanate component described later so that the hydroxyl group in the polyol component is excessive with respect to the isocyanate group in the polyisocyanate component. When the hydroxyl group equivalent in the polyol component is X and the ratio when the isocyanate group equivalent in the polyisocyanate component is Y is X / Y, the hydroxyl group residual prepolymer is such that X / Y is greater than 3 and less than 20. The polyol component and the polyisocyanate component are preferably mixed and reacted. By setting X / Y to a value greater than 3, it is possible to suppress an increase in the molecular weight of the hydroxyl group-retaining prepolymer and maintain a viscosity that is easy to handle. By setting X / Y to a value smaller than 20, the effect of the prepolymer tends to be obtained effectively. The reaction time for synthesizing the hydroxyl group-remaining prepolymer can be shortened by adding a catalyst. However, in order to avoid coloring of the polymer, it is preferable to carry out the reaction at room temperature or with heating in the absence of a catalyst. .

(Polyisocyanate component)
The polyisocyanate component according to the present invention is a component composed of a compound having two or more isocyanate groups, and includes an alicyclic polyisocyanate and a prepolymer in which the isocyanate group of the alicyclic polyisocyanate remains. The isocyanate group content of the polyisocyanate component is preferably 30.0% or less.

  The alicyclic polyisocyanate preferably has two or three isocyanate groups, and at least one isocyanate group is bonded to the secondary carbon constituting the alicyclic group. Specific examples include isophorone diisocyanate, 4,4′-methylenebis- (cyclohexyl isocyanate), 1,3-bis- (isocyanatomethyl) cyclohexane, or norbornene diisocyanate (2,5- (2,6) -bis-isocyanate. Netomethyl [2,2,1] heptane) and the like, and isophorone diisocyanate is preferred. By using such an alicyclic polyisocyanate, it becomes easy to adjust the refractive index at 589.3 nm of the cured product of the urethane resin composition excluding the inorganic oxide particles to 1.52 or less.

  Since the polyisocyanate component contains the isocyanate group residual prepolymer together with the alicyclic polyisocyanate, the polarity difference from the polyol component can be reduced, so that the compatibility with the polyol component is excellent, and the curing is uniform and has a high glass transition temperature. You can get things. In particular, when an isophorone diisocyanate having an isocyanate group bonded to a primary carbon and an isocyanate group bonded to a secondary carbon is used as the alicyclic polyisocyanate, the balance between rigidity and flexibility is excellent, and the glass transition A cured product having a high temperature can be obtained.

  The isocyanate group-remaining prepolymer is obtained by reacting the alicyclic polyisocyanate monomer and the polyol monomer so that the isocyanate group in the polyisocyanate is excessive with respect to the hydroxyl group in the polyol. can get. The isocyanate group-remaining prepolymer is preferably obtained by reacting X / Y in a ratio exceeding 0.05 and less than 0.3, where X is the hydroxyl group equivalent of the polyol and Y is the isocyanate group equivalent of the polyisocyanate. . By setting X / Y to a value smaller than 0.3, an increase in the molecular weight of the isocyanate group-remaining prepolymer can be suppressed and the viscosity can be kept easy to handle. Moreover, it exists in the tendency which can obtain the effect of a prepolymer effectively by making X / Y into a value larger than 0.05. The reaction time for the synthesis of the isocyanate group-remaining prepolymer can be shortened by adding a catalyst. However, in order to avoid coloration of the polymer, the reaction can be performed at room temperature or with heating to avoid polymer coloring. preferable.

  The polyol compound used for the synthesis of the isocyanate group-remaining prepolymer is not particularly limited, but it is preferable to use the same polyol compound as the above polyol component from the viewpoint of improving the compatibility with the above polyol component.

  When the polyisocyanate monomer and the polyol monomer are reacted, a raw material polyisocyanate monomer and a mixture of a plurality of reaction products are obtained in the reaction product. For example, when a diisocyanate compound and a trifunctional polyol compound such as trimethylolpropane are reacted at a molar ratio that the diisocyanate compound is excessive, the diisocyanate compound is 1 mol, 2 mol, 3 mol, and 1 mol of the polyol compound. A mixture of the reacted compound and the starting diisocyanate compound is obtained. The isocyanate group residual prepolymer may be a mixture thereof.

  The polyisocyanate component is a mixture of an alicyclic polyisocyanate and an isocyanate group remaining prepolymer, and the isocyanate group content means the isocyanate group content of the mixture. The isocyanate group content of the polyisocyanate component can be determined by dissolving the polyisocyanate component in methyl ethyl ketone, adding di-n-bitylamine, and back titrating with a hydrochloric acid solution using a bromophenol blue solution as an indicator.

  The polyisocyanate component may be used in combination with another polyisocyanate compound in order to adjust the crosslinking density and viscosity. In that case, it is preferable that content of another polyisocyanate compound shall be 20 mass% or less with respect to the whole quantity of a polyisocyanate component. By setting to such a range, even when several kinds of polyisocyanate compounds are used in combination, it is possible to prevent non-uniformity of the cured product of the urethane resin composition caused by a difference in reactivity between the polyisocyanate compounds.

  Examples of other polyisocyanate compounds that can be used in combination include isocyanurate type, biuret type, or adduct type polyisocyanates using polyisocyanate as a raw material. By using such polyisocyanates, the Tg of the cured product of the urethane resin composition obtained can be improved.

(Inorganic oxide particles)
The inorganic oxide particles preferably contain a composition containing SiO ₂ , Al ₂ O ₃ and CaO, and further containing boron oxide (B ₂ O ₃ ), fluorine (F ₂ ), zinc oxide (ZnO ₂ ), etc. It is preferable that the refractive index is adjusted to 1.50 to 1.52. Thereby, the difference in refractive index between the inorganic oxide particles and the cured product obtained by curing the urethane resin composition excluding the inorganic oxide particles can be set to 0.02 or less.

  The inorganic oxide particles are dispersed in the liquid A containing a polyol component. This is to prevent the hydroxyl group on the surface of the inorganic oxide particles from reacting with the isocyanate group when dispersed in the B liquid containing the polyisocyanate component.

  The amount of inorganic oxide particles dispersed in the liquid A is desirably 30% by mass or less based on the total amount of the liquid A and the liquid B. Thereby, the fall of the light transmittance of a urethane resin composition can be suppressed. When the amount of the inorganic oxide particles exceeds 30% by mass, the light transmittance may be remarkably reduced.

  The particle diameter of the inorganic oxide particles is preferably set in the range of 0.1 to 100 μm in terms of average particle diameter. When the minimum particle size is 0.1 μm or less, the surface area is large, and thus the viscosity may be remarkably increased when the liquid A is filled. On the other hand, when the maximum particle diameter exceeds 100 μm, the particles may be clogged by a resin mold flow path during mold molding or a syringe during cast molding. Moreover, you may adjust a viscosity and light transmittance by using together the some inorganic oxide particle from which an average particle diameter differs.

  Inorganic oxide particles may be treated with a coupling agent in order to improve wettability with the urethane resin composition. Examples of the coupling agent include silane coupling agents having an epoxy group, a ureido group, and the like.

  In order to disperse the inorganic oxide particles in the liquid A, a predetermined amount of the inorganic oxide particles can be added to the polyol component, and the dispersion treatment can be performed by a rotary stirring method. At this time, it is preferable to sufficiently disperse the aggregates of the inorganic oxide particles so that the air present in the polyol component or in the gaps between the polyol component and the inorganic oxide particles is defoamed under reduced pressure. It is desirable to perform distributed processing by the law.

(Other materials)
In addition to the above, liquid A or liquid B of this embodiment is an antioxidant, a curing catalyst, a coupling agent, an adhesion-imparting agent, a release agent, a light stabilizer, an ultraviolet absorber, an organic filler, and a polymerization inhibitor. Etc. may be included. Further, from the viewpoint of moldability, a plasticizer, an antistatic agent, a flame retardant, and the like may be included.

(Antioxidant)
Examples of the antioxidant include hindered phenol-based, sulfur-based and phosphorus-based antioxidants. Among these, it is particularly preferable to use one or more hindered phenolic and sulfur antioxidants alone or in combination. Specific examples of the antioxidant include [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyl} -1,1-dimethylethyl] -2,4,8,10. -Tetraoxaspiro [5,5] undecane and the like.

  It is preferable that content of antioxidant is 0.05-5 mass% with respect to the total amount of a polyol component and a polyisocyanate component, and it is more preferable that it is 0.05-0.3 mass%. When the content of the antioxidant is 0.05% by mass or more, the effect as an antioxidant tends to be effectively obtained, and when the content is 5% by mass or less, the surface of the cured product when dissolved or cured. There is a tendency that problems such as precipitation on the surface are less likely to occur. By adding the antioxidant, deterioration of the cured product of the urethane resin composition due to heat or light can be suppressed.

(Curing catalyst)
In order to increase the curability of the urethane resin composition, a curing catalyst may be included. The curing catalyst is preferably contained in the liquid B. Curing catalysts include organometallics such as zinc, zirconium or aluminum, tins such as dibutyltin laurate, DBU (1,8-diazabicyclo [5,4,0] undecan-7-ene) phenol salts, octyl Catalysts such as acid salts, amines, and imidazoles can be used. Among these, zinc stearate is preferable because it is excellent in heat resistant colorability and viscosity stability at room temperature of the urethane resin composition. From the viewpoint of the transparency of the cured product, it is preferable to use zinc stearate having a bulk density of 0.12 g / ml or less as the curing catalyst.

  The content of the curing catalyst is preferably 0.001 to 1% by mass and more preferably 0.002 to 0.1% by mass with respect to the total amount of the urethane resin composition. When the content of the curing catalyst is 0.001% by mass or more, the effect of promoting curing tends to appear, and when it is 1% by mass or less, the cloudiness of the cured product tends to be suppressed.

(Coupling agent)
In order to improve the adhesiveness between the urethane resin composition and the adherend, various coupling agents may be contained. Examples of the coupling agent include silane coupling agents having an epoxy group, a ureido group, and the like. It is preferable that content of the coupling agent in a urethane resin composition is 0.1-2 mass% with respect to the whole quantity of a polyol component and a polyisocyanate component.

(Adhesiveness imparting agent)
In order to improve the adhesiveness between the urethane resin composition and silver plating, palladium plating, or the like, the urethane resin composition may contain a compound having a thiol group as an adhesiveness imparting agent. As the compound having a thiol group, a thiol group-containing silane coupling agent such as γ-mercaptopropyltrimethoxysilane or a compound having two or more thiol groups (hereinafter referred to as polythiol) is preferable. Compound bonded to primary carbon, compound bonded to secondary carbon with thiol group, one or more thiol groups bonded to primary carbon, and one or more thiol groups bonded to secondary carbon And the like.

(Release agent)
When a urethane resin composition is molded to obtain a cured product, various mold release agents may be contained from the viewpoint of improving the mold releasability from the mold. As the release agent, a fatty acid release agent or a silicone release agent can be used alone or in combination of two or more. Examples of the fatty acid release agent include saturated fatty acids represented by the following general formula (1).
R ¹ —COOH (1)

In the formula, R ¹ represents a linear or branched hydrocarbon group having 7 to 28 carbon atoms.

Examples of the saturated fatty acid include caprylic acid, pelargonic acid, lauric acid, myristylic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, isostearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, and montanic acid. Can be mentioned. In general formula (1), the carbon number of R ¹ is usually 7 to 28, preferably 10 to 22, and more preferably 14 to 18. Among these, isostearic acid having 17 carbon atoms is particularly preferable in that it is a liquid and can adjust the viscosity of the urethane resin composition.

  Various modified silicones can be used as the silicone release agent. Examples thereof include a silicone-caprolactone block copolymer represented by the following general formula (2).

In the formula, m and n are positive integers satisfying m / n of 0.5 to 1.0. R ² and R ³ each independently represent a divalent hydrocarbon group or a polyether chain.

  In the formula (2), when the ratio of m / n is 0.5 or more, compatibility with other materials is high, and problems such as white turbidity in the cured body can be suppressed. Moreover, if the ratio of m / n is 1.0 or less, it is possible to obtain excellent releasability from the molding die. The silicone-caprolactone block copolymer preferably has a weight average molecular weight of 16000 or less from the viewpoint of excellent solubility.

  The saturated fatty acid and the silicone-caprolactone block copolymer are preferably added to the B liquid containing a polyisocyanate component from the viewpoint of solubility.

  The content of the release agent is preferably more than 0.01% by mass and less than 5.0% by mass with respect to the total amount of the polyol component and the polyisocyanate component. When the content of the release agent is larger than 0.01% by mass, the mold release property tends to be excellent, and when it is smaller than 5.0% by mass, the heat resistance such as glass transition temperature of the cured product is high. It tends to suppress the decrease.

(Optical adhesive)
In addition to being able to be used as a two-component adhesive, the urethane resin composition of the present embodiment can also be used as a one-component adhesive that is stored frozen after two-component mixing. The adhesive is used for adhesion between the adherend and the adherend, and is suitable for an adhesive for optical applications because of its high light transmittance and low stress, which are the characteristics of this resin.

(Cured product)
The hardened | cured material of the urethane resin composition of this embodiment can be manufactured by mixing A liquid containing a polyol component, and B liquid containing a polyisocyanate component, heating this and making it react. The mixing ratio of the polyol component and the polyisocyanate component, and the mixing ratio of the hydroxyl group remaining prepolymer and the isocyanate group remaining prepolymer are (total hydroxyl group equivalent of polyol and hydroxyl group remaining prepolymer) / (poly The total isocyanate group equivalent amount of isocyanate and isocyanate group remaining prepolymer) is preferably 0.7 to 1.3, more preferably 0.8 to 1.1. When the mixing ratio is in the range of 0.7 to 1.3, the heat resistance, optical properties, and mechanical properties of the cured product tend to be improved.

  When a cured product is produced by a casting method or a potting method using the urethane resin composition of the present embodiment, it depends on the type, combination, and addition amount of each component, but at 60 to 150 ° C. for 1 to 10 hours. It is preferable to heat cure to a certain extent, and it is particularly preferable that the temperature is about 80 to 150 ° C. for about 1 to 10 hours. Moreover, in order to reduce the internal stress generated by the rapid curing reaction, it is desirable to raise the curing temperature stepwise.

  When a cured product is produced by a mold molding method using the urethane resin composition of the present embodiment, it is desirable to use liquid transfer molding or compression molding. In this case, the gelation time of the resin composition is preferably 25 to 200 seconds at the molding temperature. When the gelation time is shorter than this, the urethane resin composition is cured before sufficiently filling the flow path in the molding die (hereinafter simply referred to as “mold”), and the molded product of the cured product is not filled. And voids tend to occur. On the other hand, when the gelation time is longer than 200 seconds, the molded product tends to be insufficiently cured. The gelation time can be adjusted by adjusting the prescription amount of the curing accelerator.

  When liquid transfer molding is performed using the two-component urethane resin composition of the embodiment, after mixing the A and B liquids of the urethane resin composition, the mixture is filled in the pot of the molding apparatus and the plunger is activated to start urethane. The resin composition is press-fitted from the pot into a mold cavity heated to a predetermined temperature via a flow path such as a runner and a gate. The mold is usually composed of a separable upper mold and a lower mold, and a cavity is formed by connecting them. Then, the urethane resin composition filled in the cavity is cured on the structure by holding the urethane resin composition in the cavity for a certain period of time. Thereby, the hardened | cured material of a urethane resin composition is shape | molded by the target shape.

  The mold temperature is preferably set to a temperature at which the urethane resin composition has high fluidity in the flow path and can be cured in a short time in the cavity. Although this temperature is dependent also on the composition of a urethane resin composition, it is suitable that it is 120-200 degreeC, for example. Moreover, it is preferable to set the pressure at which the urethane resin composition is press-fitted into the cavity so that the urethane resin composition can be filled in the entire cavity without any gap, and specifically, 2 MPa or more. Is preferred. When the spray pressure is 2 MPa or more, unfilled portions in the cavity and voids tend not to be generated.

  In order to make it easy to take out the cured product of the urethane resin composition from the mold, it is possible to apply or spray a release agent on the inner wall surface of the mold that forms the cavity. Furthermore, in order to suppress generation | occurrence | production of the void in hardened | cured material, you may use the well-known decompression molding apparatus which can pressure-reduce the inside of a cavity.

  In the liquid transfer molding and compression molding methods described above, the curing time can be set short, and the productivity of cured product production is improved.

(Optical molded product)
Since the urethane resin composition of the present embodiment can be molded into an arbitrary shape by a method such as casting, potting, or mold molding, it can be used as an optical molded body such as a lens or a sheet.

(Semiconductor device)
FIG. 1 is a cross-sectional view schematically showing one embodiment of an optical semiconductor device. An optical semiconductor device 100 shown in FIG. 1 is a surface-mounted light-emitting diode including a light-emitting diode element 2 and a transparent sealing member 1 provided so that the light-emitting diode element 2 is sealed. The light emitting diode element 2 is arranged at the bottom of the cavity 10 formed in the case member 5. The light emitting diode element 2 is bonded to the case member 5 via an adhesive member 20 and connected to the lead frame 7 via a wire 8.

  The sealing member 1 covers the light emitting diode element 2 and fills the cavity 10. The sealing member 1 is formed by, for example, a method in which the urethane resin composition of the above embodiment is poured into the cavity 10 and the urethane resin composition in the cavity 10 is cured by heating.

  FIG. 2 is a cross-sectional view schematically showing one embodiment of an optical semiconductor device. An optical semiconductor device 200 shown in FIG. 2 includes a pair of lead frames 102 (102a and 102b), an adhesive member 103 provided on one lead frame 102a, and an optical semiconductor element 104 provided on the adhesive member 103. A wire 105 that electrically connects the optical semiconductor element 104 and the other lead frame 102b, and a part of the pair of lead frames 102, an adhesive member 103, an optical semiconductor element 104, and a sealing member 106 that seals the wire 105 And have. The optical semiconductor device 200 is called a surface mount type.

  The lead frame 102 includes one lead frame 102a and the other lead frame 102b. The lead frame 102 is a member made of a conductive material such as metal, and the surface thereof is usually covered with silver plating. Also, one lead frame 102a and the other lead frame 102b are separated from each other. The adhesive member 103 is a member for bonding and fixing one lead frame 102a and the optical semiconductor element 104 to each other and electrically connecting them. The adhesive member 103 is formed from, for example, a silver paste.

  Examples of the optical semiconductor element 104 include a light emitting diode element that emits light when a voltage is applied in the forward direction. The wire 105 is a conductive wire such as a thin metal wire that can electrically connect the optical semiconductor element 104 and the other lead frame 102b.

  The sealing member 106 is formed of a cured product of the urethane resin composition of the above embodiment. Since the sealing member 106 protects the optical semiconductor element 104 from the outside air and plays a role of taking out light emitted from the optical semiconductor element 104 to the outside, it has high light transmittance. In the present embodiment, the sealing member 106 collects light emitted from the optical semiconductor element 104 by the lens portion 106b having a convex lens shape.

  The optical semiconductor device 200 of the present embodiment described above can employ liquid transfer molding or compression molding as part of its manufacturing process, thereby shortening the molding time and improving productivity. . Further, by adopting liquid transfer molding or compression molding, an effect of providing a lens shape that improves the light extraction efficiency as shown in FIG. 2 can be obtained.

  The optical semiconductor device 200 only needs to include an optical semiconductor element and a sealing member that seals the optical semiconductor element, and may be a shell type instead of the surface mount type as described above.

  Since the cured product of the urethane resin composition according to the present embodiment described above has high light transmittance and low stress, it is difficult to peel off from the adherend, and an optical semiconductor device excellent in connection reliability is manufactured. be able to.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these at all. The blending ratio is expressed in parts by mass unless otherwise specified.

(Resin composition A)
As a polyol component, 2 mol of propylene oxide was added to 1 mol of trimethylolpropane to prepare a polyol (A2) having a hydroxyl value of 670 (mg / g KOH), and a polyol component A ′ solution was obtained.

  Meanwhile, 88.80 parts by mass of isophorone diisocyanate (Degussa VESTANAT IPDI) (B1) and 8.93 parts by mass of trimethylolpropane (Mitsubishi Gas Chemical Co., Ltd.) were reacted at 80 ° C. for 8 hours with stirring in a nitrogen atmosphere. Thus, a prepolymer (P1) having a remaining isocyanate group was produced. 12.9 parts by mass of isophorone diisocyanate (B1) is added to 52.3 parts by mass of this isocyanate group residual prepolymer (P1), and [2- {3- (3-tert-butyl-] is used as a hindered phenolic antioxidant. 4-hydroxy-5-methylphenyl) propionyl} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumilyzer GA-80) ) (D) 0.1 parts by mass was mixed to obtain a liquid B containing a polyisocyanate component having an isocyanate group content of 28.02%.

  37.1 parts by mass of the above polyol component A ′ liquid and 64.3 parts by mass of B liquid were mixed and stirred at room temperature to prepare a urethane resin composition, and the refractive index of the cured product at 589.3 nm was measured. As a result, it was 1.50.

(Resin composition B)
As a polyol component, 3 mol of propylene oxide was added to 1 mol of trimethylolpropane to prepare a polyol (A3) having a hydroxyl value of 550 (mg / g KOH), and a polyol component A ′ solution was obtained.

  On the other hand, 11.0 parts by mass of isophorone diisocyanate (B1) was added to 48.3 parts by mass of the residual isocyanate group prepolymer (P1) of Example 1, and a hindered phenolic antioxidant (manufactured by Sumitomo Chemical Co., Ltd., trade name Smizer). GA-80) (D) 0.1 mass part was mixed, and the B liquid containing the polyisocyanate component of isocyanate group content rate 28.02% was obtained.

  40.6 parts by mass of the liquid containing the polyol component and 59.4 parts by mass of B liquid were mixed and stirred at room temperature to produce a urethane resin composition, and the refractive index of the cured product was measured at 589.3 nm. As a result, it was 1.50.

(Resin composition C)
As a polyol component, 1 mol of propylene oxide is added to 1 mol of trimethylolpropane, and 61.81 parts by mass of a polyol (A1) having a molecular weight of 192 and a hydroxyl value of 880 (mg / g KOH) is produced, and further adhesion is imparted. As the agent, 1.06 parts by mass of γ-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM-803) (F) was added and stirred until uniform to obtain a polyol component A ′ solution.

On the other hand, 1.56 parts by mass of trimethylolpropane and 22.93 parts by mass of 4,4′-methylenebis- (cyclohexyl isocyanate) (manufactured by Degussa, trade name H ₁₂ MDI) were mixed and mixed at 80 ° C. in a nitrogen atmosphere at 80 ° C. The mixture was heated and stirred for a time to obtain an isocyanate group residual prepolymer (P2). As the polyisocyanate component, 24.49 parts by mass of the above isocyanate group residual prepolymer (P2), 4,4′-methylenebis- (cyclohexyl isocyanate) (B2) 22.93 parts by mass, norbornene diisocyanate (Mitsui Takeda Chemical Co., Ltd., Brand name Cosmonate NBDI) (B3) 41.8 parts by mass, 75 mass% butyl acetate solution of isocyanurate type polyisocyanate which is a trimer of isophorone diisocyanate (manufactured by Degussa, trade name Vestanat T1890ME) (B4) 82. 00 parts by mass and 0.1 part by mass of a hindered phenol-based antioxidant (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumilizer GA-80) (D) were mixed, and butyl acetate was heated and dissolved under reduced pressure. On the other hand, isostearic acid (trade name isostearic acid EX manufactured by Higher Alcohol Industry Co., Ltd.) (E1) 5.34 parts by mass and silicone-caprolactone copolymer (E2) 1.07 parts by mass as a release agent as a polyisocyanate component. In addition, it was heated and mixed at 80 ° C. for 2 hours. The silicone-caprolactone copolymer (E2) was prepared by adding 22 mol of caprolactone to 1 mol of both-end polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-22-4952). ) M / n = 0.6 and weight average molecular weight Mw = 4,000. Thereafter, after cooling to room temperature, 0.11 part by mass of zinc stearate (trade name MZ-2, manufactured by NOF Corporation) (C) is added as a curing catalyst, and the mixture is stirred until uniform, and contains a polyisocyanate component. A liquid was prepared.

  A urethane resin composition is prepared by stirring 62.87 parts by mass of the polyol component-containing liquid and 157.44 parts by mass of B liquid until uniform at room temperature, and the cured product is refracted at 589.3 nm. When the rate was measured, it was 1.51.

  Table 1 shows the compositions of the resin compositions A, B, and C.

Example 1
Average particle having 32.0 parts by mass of A ′ liquid of resin composition A and containing SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , CaO and F ₂ and having a refractive index at 589.3 nm of 1.50 10.0 parts by mass of inorganic oxide particles α having a diameter of 35 μm (manufactured by Nippon Frit Co., Ltd., trade name CF0093) were dispersed by a vacuum rotation stirring process to prepare a liquid A. 44.0 parts by mass of A liquid and 58.0 parts by mass of B liquid of resin composition A were mixed and stirred at room temperature to obtain a urethane resin composition.

(Example 2)
A solution A was prepared by dispersing 25.0 parts by mass of the inorganic oxide particles α in 26.8 parts by mass of the A ′ solution of the resin composition A by a reduced-pressure rotation stirring process. 41.8 parts by mass of B liquid of resin composition A was mixed and stirred at room temperature to 51.8 parts by mass of A liquid to obtain a urethane resin composition.

(Example 3)
In 26.8 parts by mass of the liquid containing the polyol component of the resin composition A, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , CaO and F ₂ are included, and the refractive index at 589.3 nm is 1.51. A solution A was prepared by dispersing 25.0 parts by mass of inorganic oxide particles β (manufactured by Potters Barotini Co., Ltd.) having an average particle size of 20 μm by a reduced pressure rotary stirring process. 41.8 parts by mass of B liquid of resin composition A was mixed and stirred at room temperature to 51.8 parts by mass of A liquid to obtain a urethane resin composition.

Example 4
10.0 parts by mass of the inorganic oxide particles α were dispersed in 36.5 parts by mass of the A ′ solution of the resin composition B by a reduced pressure rotary stirring process to prepare A liquid. 46.5 parts by mass of A liquid and 53.5 parts by mass of B liquid of resin composition B were mixed and stirred at room temperature to obtain a urethane resin composition.

(Example 5)
In 25.7 parts by mass of the A ′ solution of the resin composition C, 10.0 parts by mass of the inorganic oxide particles α were dispersed by a reduced pressure rotary stirring process to prepare A liquid. 65.7 parts by mass of B liquid of resin composition C were mixed and stirred at 35.7 parts by mass of A liquid at room temperature to obtain a urethane resin composition.

(Comparative Example 1)
65.7 parts by mass of B liquid of resin composition A were mixed and stirred at 35.7 parts by mass of A ′ liquid of resin composition A at room temperature to obtain a urethane resin composition.

(Comparative Example 2)
Inorganic oxide particles γ (manufactured by Denki Kagaku Kogyo Co., Ltd.), which is fused silica having an average particle diameter of 25 μm, having a refractive index of 58. (Product name FB950) 10.0 parts by mass was dispersed by a reduced-pressure rotary stirring process to prepare A liquid. 42.1 parts by mass of A liquid and 57.9 parts by mass of B liquid of resin composition A were mixed and stirred at room temperature to obtain a urethane resin composition.

  The urethane resin compositions of Examples and Comparative Examples were evaluated according to the following methods.

<Production of optical semiconductor package (optical semiconductor device)>
The urethane resin compositions obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were placed in the cavity of a surface-mounted package mounted with light-emitting elements having an outer shape of 5 mm × 5 mm × 1 ^t mm and a cavity diameter of 4 mm. And filled with a potting method and heated and cured at 100 ° C. for 1 hour, 125 ° C. for 1 hour, and 150 ° C. for 4 hours to produce an optical semiconductor package as shown in FIG.

  Further, the urethane resin composition obtained in Example 5 was molded using a liquid transfer molding machine under conditions of a mold temperature of 165 ° C., a spray pressure of 9.8 MPa, an injection time of 30 seconds, and a curing time of 120 seconds. After curing in an oven at 150 ° C. for 4 hours, an optical semiconductor package as shown in FIG. 2 was produced.

<Coefficient of thermal expansion>
The thermal expansion coefficient of the cured product of the urethane resin composition was measured using a thermomechanical analyzer. Table 2 shows the thermal expansion coefficient (α1) in the temperature range below the glass transition temperature.

<Flux ratio>
The luminous flux ratio was evaluated as the optical characteristics of the produced optical semiconductor package. The luminous flux ratio was obtained by normalizing the luminous flux of the optical semiconductor packages of Examples 1 to 4 and Comparative Example 2 with the luminous flux of the optical semiconductor package of Comparative Example 1. On the other hand, the light flux ratio of the optical semiconductor package of Example 5 is the same as that of the optical semiconductor package of Example 5 using the urethane resin composition of Comparative Example 1 as the light flux amount of the optical semiconductor package of Example 5. It was obtained by standardizing with the luminous flux of the semiconductor package. The results are shown in Table 2.

<Thermal shock test>
Thermal shock resistance was evaluated as the reliability of the produced optical semiconductor package. The evaluation conditions were −40 ° C .: 5 minutes, room temperature: 30 seconds, 110 ° C .: 5 minutes, and the presence or absence of peeling between the cured resin and the element or lead frame was examined during 500 cycles. The results are shown in Table 2. In an optical semiconductor package with 8 samples, “A” was shown when no peeling was observed, and “B” was shown when there was even one peeling.

  Compared with the optical semiconductor package of Comparative Example 1, the optical semiconductor packages of Examples 1 to 5 showed a small decrease in the light flux ratio, and no delamination was observed in the thermal shock resistance test. Therefore, it was confirmed that the hardened | cured material of the urethane resin composition of Examples 1-5 has sufficiently high light transmittance, and has fully reduced the stress. On the other hand, although the optical semiconductor package of Comparative Example 2 was not peeled off in the thermal shock resistance test, it was confirmed that the light flux ratio was greatly reduced and the light transmittance was not sufficient.

  DESCRIPTION OF SYMBOLS 1,106 ... Sealing member, 2 ... Light emitting diode element, 5 ... Case member, 7, 102, 102a, 102b ... Lead frame, 8, 105 ... Wire, 10 ... Cavity, 20, 103 ... Adhesive member, 100, 200 DESCRIPTION OF SYMBOLS ... Optical semiconductor device, 104 ... Optical semiconductor element, 106a ... Flat plate part, 106b ... Lens part.

Claims (7)

A two-component urethane resin composition comprising a liquid A containing a polyol component and inorganic oxide particles, and a liquid B containing a polyisocyanate component,
The polyol component contains a trifunctional or higher functional polyol having a hydroxyl value of 550 to 900 mgKOH / g,
The polyisocyanate component has an alicyclic group and two or three isocyanate groups, and at least one isocyanate group is bonded to a secondary carbon constituting the alicyclic group. Containing a compound,
The difference between the refractive index of the cured product obtained by mixing the liquid obtained by removing the inorganic oxide particles from the liquid A and the liquid B at a wavelength of 589.3 nm and the refractive index of the inorganic oxide particles However, it is 0.02 or less, 2 liquid type urethane resin composition.   The two-component urethane resin composition according to claim 1, wherein the cured product and the inorganic oxide particles have a refractive index of 1.52 or less at a wavelength of 589.3 nm.   The two-component urethane resin composition according to claim 1 or 2, wherein the inorganic oxide particles contain silicon dioxide, aluminum oxide, and calcium oxide.   The two-component urethane resin composition according to any one of claims 1 to 3, wherein a content of the inorganic oxide particles is 30% by mass or less based on a total amount of the liquid A and the liquid B. object.   The optical adhesive agent containing the 2 liquid type urethane resin composition as described in any one of Claims 1-4.   An optical molded body obtained by curing the two-component urethane resin composition according to any one of claims 1 to 4.   An optical semiconductor device provided with the sealing member which consists of hardened | cured material obtained by hardening | curing the 2 liquid type urethane resin composition as described in any one of Claims 1-4.

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