JP2012233035A - Addition-curable silicone composition and optical semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an addition-curable silicone composition having self adhesiveness that has a moderate viscosity (dischargeability), is excellent in nonfluidity (shape stability at heat curing) and light reflecting properties, and used especially for light reflecting material for LEDs, and an optical semiconductor device using the addition-curable silicone composition.SOLUTION: The self-adhesive addition-curable silicone composition for optical semiconductor devices includes: (A) 100 pts.mass of an organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule; (B) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom and at least one alkoxy group in one molecule, wherein the number of total Si-H groups is 1.4-5.0 times the number of total alkenyl groups of the component (A); (C) 8-30 pts.mass of aerosol silica with respect to 100 pts.mass of the sum of the components (A) and (B); (D) a white pigment; and (E) a curing catalyst.

Description

  The present invention has an appropriate viscosity (dischargeability), excellent non-fluidity (shape stability during heat curing) and light reflectivity, and particularly has self-adhesiveness used for light reflecting materials for LEDs. The present invention relates to an addition-curable silicone composition and an optical semiconductor device using the same.

  In recent years, LEDs have been tried to be used for notebook computers, liquid crystal televisions, and the like. Uniform lighting of a large screen is achieved by arranging a large number of side view type LEDs and top view type LEDs. On the other hand, there is also a method of forming a sealing material in a dome shape on a circuit board in which LED chips and wires are connected on a substrate called a map substrate. This sealing material can be molded by dripping a few drops of liquid silicone and curing by heating. However, there is a problem that the sealing cannot be effectively performed because the viscosity decreases and spreads before curing starts. . In addition, although fumed silica can be added to give the sealing material itself flow stop performance, the appearance becomes milky white when added to silicone with dimethylpolysiloxane as the main component, which has high heat resistance and light resistance. was there.

  Under such circumstances, as a method for stabilizing the shape of the sealing material, a method of making a dam like a material having high shape stability and potting the sealing material therein was considered. . As a material for forming such a dam, a moisture-curing silicone rubber composition that cures without heating is considered suitable. In fact, there are many cases in which the shape before and after application is not deformed even when cured. However, it cannot be used because it takes a long curing time from half a day to several days and the curing agent for crosslinking exerts a curing inhibition on the crosslinking of the addition-curable silicone sealing material.

  In addition, the following literature is mentioned as a prior art relevant to this invention.

Japanese Patent Laid-Open No. 06-306290 JP 2001-164187 A JP 2008-074881 A

  The present invention has been made in view of the above circumstances, and is excellent in moderate viscosity (dischargeability), non-fluidity (shape stability at the time of heat curing) and light reflectivity, and particularly used for a light reflecting material for LED. An object of the present invention is to provide a self-adhesive addition-curable silicone composition and an optical semiconductor device using the same.

As a result of intensive studies to achieve the above object, the present inventors have
(A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass
(B) Organohydrogenpolysiloxane having hydrogen atoms bonded to at least two silicon atoms and at least one alkoxy group in one molecule: the total number of Si-H groups relative to the total number of alkenyl groups in the component (A) Is 1.4 to 5.0 times,
(C) Smokeous silica: 8 to 30 parts by mass with respect to a total of 100 parts by mass of components (A) and (B),
(D) a white pigment,
(E) A self-adhesive addition curable silicone composition for an optical semiconductor device containing a curing catalyst can be applied to a substrate using a dispensing device, and the applied shape is maintained even when heat-cured, and is good. The present inventors have found that it becomes a light reflecting material having self-adhesiveness, and has made the present invention.

Accordingly, the present invention provides the following addition-curable silicone composition and an optical semiconductor device using the same.
[Claim 1]
(A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass
(B) Organohydrogenpolysiloxane having hydrogen atoms bonded to at least two silicon atoms and at least one alkoxy group in one molecule: the total number of Si-H groups relative to the total number of alkenyl groups in the component (A) Is 1.4 to 5.0 times,
(C) Smokeous silica: 8 to 30 parts by mass with respect to a total of 100 parts by mass of components (A) and (B),
(D) a white pigment,
(E) A self-adhesive addition-curable silicone composition for an optical semiconductor device containing a curing catalyst.
[Claim 2]
When using an E-type viscometer, the viscosity at 25 ° C. when the rotational speed is 1 rpm is 70 Pa · s to 500 Pa · s, and the ratio to the viscosity at 25 rpm (25 ° C.) (1 rpm / 5 rpm viscosity ratio (thixo 2. The silicone composition according to claim 1, wherein the coefficient)) is 2.5 or more.
[Claim 3]
The silicone composition according to claim 1 or 2, wherein a ratio of height / width before and after curing of the silicone composition applied from a needle to a substrate by a dispensing device is 0.8 or more. object.
[Claim 4]
The silicone composition according to any one of claims 1 to 3, wherein a sheet obtained by molding and curing the addition-curable silicone composition with a thickness of 2 mm has a light reflectivity of 450 nm light of 90% or more.
[Claim 5]
A height of 0 for preventing the uncured liquid sealing material from flowing out by the silicone composition according to any one of claims 1 to 4 using a dispensing device on the substrate of the optical semiconductor device. A step of forming a dam of 5 mm or more, a step of heat-curing the dam of the silicone composition, if necessary, a step of potting a sealing material in the dam, and a curing of the dam of the sealing material or the silicone composition If not, a method for manufacturing an optical semiconductor device comprising the step of integrally forming the sealing material by heat-curing the sealing material.
[Claim 6]
An optical semiconductor device obtained by the method according to claim 5.

  The addition-curable silicone composition of the present invention has an appropriate viscosity and thus excellent dischargeability, and has non-fluidity and thus excellent shape stability during heat curing, and the cured product of the composition has light reflectivity. And is particularly suitable as a light reflecting material for LED.

Hereinafter, the present invention will be described in more detail.
The organopolysiloxane of component (A) is the main component (base polymer) of this composition, and contains an alkenyl group bonded to two or more silicon atoms in one molecule, preferably the following average composition What is shown by Formula (1) is used.
R _a SiO _{(4-a) / 2} (1)
(In the formula, R is an identical or different monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and a is 1.5 to 2.8, preferably 1. (It is a positive number in the range of 8 to 2.5, more preferably 1.95 to 2.05.)

  (A) As an alkenyl group couple | bonded with the silicon atom in a component, it is C2-C8 normally, preferably 2-C, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, for example. 6 are preferable, and a vinyl group is particularly preferable.

  Examples of the position of the silicon atom to which the alkenyl group in the polysiloxane skeleton of the component (A) is bonded include the molecular chain terminal and / or the molecular chain middle (non-molecular chain terminal). A linear diorganopolysiloxane containing alkenyl groups bonded to silicon atoms at both ends of the molecular chain is preferred. In addition, the content of the alkenyl group in the component (A) is a monovalent organic group bonded to a silicon atom (that is, an unsubstituted or substituted monovalent hydrocarbon represented by R in the average composition formula (1)). Group) is preferably about 0.001 to 10 mol%, particularly about 0.01 to 5 mol%, based on the whole.

  Examples of the organic group bonded to the silicon atom other than the alkenyl group as component (A) include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group and heptyl group; phenyl Groups, tolyl groups, xylyl groups, naphthyl groups and other aryl groups; benzyl groups, phenethyl groups and other aralkyl groups; chloromethyl groups, 3-chloropropyl groups, 3,3,3-trifluoropropyl groups and other alkyl halides Examples thereof include an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, such as a group, preferably a methyl group and a phenyl group, and particularly a methyl group. Is preferred.

  Examples of the molecular structure of the component (A) include linear, cyclic, and branched chains. The main chain is basically composed of repeating diorganosiloxane units, and both ends of the molecular chain are tricyclic. A linear diorganopolysiloxane blocked with an organosiloxy group is preferred (the organo group herein may also include an alkenyl group).

The viscosity of component (A) at 25 ° C. is within the range of 100 to 500,000 mPa · s because the physical properties of the resulting silicone rubber are good and the workability of the composition is good. It is preferable that it is within a range of 600 to 100,000 mPa · s, more preferably 1,000 to 30,000 mPa · s. The viscosity in the present invention is measured by a rotational viscometer (hereinafter the same).
In addition, what is necessary is just to make it the viscosity after mixing become the said viscosity, when using (A) component as a 2 or more types of mixture.

Examples of the organopolysiloxane of the component (A) include, for example, a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer, a molecular chain both-ends trimethylsiloxy group-capped methylvinylpolysiloxane, and both molecular chains. Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylvinylsiloxy group-blocked methylvinylpolysiloxane, molecular chain both ends Dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane copolymer, dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer , Both ends of the molecular chain divinylmethylsiloxy group-blocked dimethylpolysiloxane, both ends of the molecular chain divinylmethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, both ends of the molecular chain trivinylsiloxy group-blocked dimethylpolysiloxane, both ends of the molecular chain Trivinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, siloxane unit represented by formula: R ¹ ₃ SiO _1/2 and siloxane unit represented by formula: R ¹ ₂ R ² SiO _1/2 and formula: R ^An organosiloxane copolymer comprising a siloxane unit represented by ¹ ₂ SiO and a siloxane unit represented by the formula: SiO ₂ , a siloxane unit represented by the formula: R ¹ ₃ SiO _1/2 and a formula: R ¹ ₂ R ² SiO _{1 /} siloxane units represented by the formula _2: organosiloxanes composed of siloxane units represented by SiO ₂ Polymers, wherein: the siloxane units represented by the formula R ^{1 ₂} R ₂ SiO _1/2: siloxane units represented by the formula R ¹ ₂ SiO: organosiloxane copolymers composed of siloxane units represented by SiO _2, wherein : A siloxane unit represented by R ¹ R ² SiO and a siloxane unit represented by the formula R ¹ SiO _3/2 or a siloxane unit represented by the formula R ² SiO _3/2 , and these The mixture which consists of 2 or more types of organopolysiloxane is mentioned.

R ¹ in the above formula is an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, etc. Alkyl groups; phenyl groups, tolyl groups, xylyl groups, naphthyl groups and other aryl groups; benzyl groups, phenethyl groups and other aralkyl groups; chloromethyl groups, 3-chloropropyl groups, 3,3,3-trifluoropropyl groups And halogenated alkyl groups. R ² in the above formula is an alkenyl group, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, and the like. Vinyl groups are most suitable for ease of use and price.

  (A) The organopolysiloxane of component may use together 2 or more types from which a polymerization degree and molecular structure differ. For example, the combined use of silicone oils having different degrees of polymerization and vinyl group contents, and the combined use of silicone oil and silicone resin can be mentioned.

In the present invention, it is preferable to use a silicone oil having at least two alkenyl groups bonded to a silicon atom in one molecule and a silicone resin in order to improve strength and adhesion. Some silicone resins are solid at 25 ° C., but are soluble in silicone oil, so that the viscosity after mixing is preferably in the above-mentioned range.
The mixing ratio of the silicone oil and the silicone resin is preferably 50:50 to 98: 2 by mass ratio, more preferably 60:40 to 95: 5, and particularly preferably 70:30 to 90:10.

The organohydrogenpolysiloxane of component (B) acts as a crosslinking agent that reacts with component (A), and there is no particular limitation on its molecular structure. For example, linear, cyclic, branched, which has been conventionally produced Various types such as a shape and a three-dimensional shape can be used, but at least 2, preferably 3 or more hydrogen atoms bonded to silicon atoms (hydrosilyl group represented by SiH) and 1 or more in one molecule Of alkoxysilyl groups, preferably 2 to 300, more preferably 3 to 200, particularly preferably 3 to 100 SiH groups, preferably 1 to 30, more preferably 2 It is preferable to have ~ 20, particularly preferably 3-10 alkoxysilyl groups. As the organohydrogenpolysiloxane, those represented by the following average composition formula (2) can be used.
R ³ _b R ⁴ _c H _d SiO _{(4-bcd) / 2} (2)

In the formula (2), R ³ is excluding alkenyl group, preferably an unsubstituted or substituted monovalent hydrocarbon group bonded 1 to 10 carbon atoms, a silicon atom, an unsubstituted or substituted in the R ³ Examples of the monovalent hydrocarbon group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-hexyl group, n- Octyl group, n-decyl group, alkyl group such as n-octadecyl group, cyclopentyl group, cyclohexyl group, cycloalkyl group such as cyclooctyl group, aryl group such as phenyl group, o-tolyl group, benzyl group, phenylethyl group Epoxy groups such as aralkyl groups such as halogen substituted alkyl groups such as 3,3,3-trifluoropropyl groups, glycidylpropyl groups and glycidoxypropyl groups Examples thereof include a substituted alkyl group. The unsubstituted or substituted monovalent hydrocarbon group for R ³ is preferably an alkyl group or an aryl group, and more preferably a methyl group or a phenyl group. Further, 50 mol% or more of R ^3, it is preferable, especially 70 to 100 mol% are methyl groups.

R ⁴ is a substituent having at least one alkoxy group, and examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. A substituent having a trialkoxysilyl group is more preferable, and a trialkoxysilyl group bonded to a silicon atom via an alkylene group is particularly preferable. Examples of such a substituent include a trimethoxysilylethyl group, a trimethoxysilylpropyl group, a triethoxysilylethyl group, and a triethoxysilylpropyl group.

  Here, b, c and d are 0.7 ≦ b ≦ 2.1, 0.001 ≦ c ≦ 0.75, 0.001 ≦ d ≦ 1.0 and 0.8 ≦ b + c + d ≦ 3.0. It is a positive number that satisfies, preferably 1.0 ≦ b ≦ 2.0, 0.01 ≦ c ≦ 0.5, 0.1 ≦ d ≦ 1.0, and 1.5 ≦ b + c + d ≦ 2.5.

  The compound of the formula (2) having a trialkoxysilyl group can be produced by a method of adding an alkenyl group-containing alkoxysilane to an organohydrogenpolysiloxane.

  The viscosity of the organohydrogenpolysiloxane at 25 ° C. is preferably 1,000 mPa · s or less, more preferably 5 to 200 mPa · s, and particularly preferably 10 to 50 mPa · s. If the viscosity is too high, the dischargeability from the syringe may decrease.

Specific examples of the component (B) include those shown below.

In the above formula, m, n, p, q, r are 0 ≦ m <200, 1 ≦ n <200, 1 ≦ p <10, 1 ≦ q <10, 1 ≦ r <10, preferably 0, respectively. ≦ m <50, 1 ≦ n <50, 1 ≦ p <5, 1 ≦ q <5, 1 ≦ r <3.
The component (B) may be a single compound or a combination of two or more compounds.

  The amount of component (B) is such that the total number of Si-H groups in component (B) is 1.4 to 5.0 times the total number of alkenyl groups in component (A), preferably 1. The amount is 4 to 3.0 times. This range is preferable from the viewpoint of rubber strength and adhesiveness.

  Component (B) is essential as a cross-linking agent / adhesion imparting agent, and has a weak interaction with a silanol group that is considered to remain on the surface of fumed silica, which is component (C) described later. Therefore, the thixotropy is high and the composition is excellent in shape stability.

(C) The fumed silica which is a component is a component which imparts thixotropy while being a reinforcing filler. In the present invention, at least 50 m ² / g, more preferably 100~450m ² / g, are fumed silicas, especially having a specific surface area by BET method of 200~380m ² / g preferred. If the specific surface area is less than 50 m ² / g, sufficient thixotropy may not be obtained. Also, in order to prevent the viscosity of the composition from increasing too much, hydrous group-containing silanes such as dimethyldichlorosilane and dimethyldimethoxysilane, alkoxysilanes and other hydrolysable group-containing silanes, and organosilicon compounds such as hexamethyldisilazane and the like. It is preferable to use a surface treated silanol.

  (C) The compounding quantity of the fumed silica which is a component is 8-30 mass parts with respect to a total of 100 mass parts of the said (A) and (B) component, Preferably it is 8-20 mass parts. By blending fumed silica at such a content ratio, the thixotropy of the composition can be improved, such that the viscosity is low and the shape after application and heat molding by the dispensing device does not change, and CF in the adhesion failure mode is also achieved. (Cohesive failure) can be maintained. If the amount of the fumed silica is less than 8 parts by mass, sufficient thixotropy cannot be obtained and the shape stability is deteriorated. If it is more than 30 parts by mass, the shape stability is excellent, but the viscosity increases. As a result, the dispensing property is deteriorated or the yarn is pulled at the tip of the discharge needle, resulting in a poor finish.

  The white pigment of component (D) is a component that colors a composition such as titanium oxide, zinc oxide, and aluminum oxide white. In the present invention, the component (D) is preferably titanium oxide from the viewpoint of light reflection. In addition, the kind of titanium oxide is not specifically limited, Any of an anatase type and a rutile type may be sufficient. Further, the surface treatment may be performed by a known surface treatment agent.

  The component (D) has an average particle size of 0.1 to 0.5 μm, preferably 0.1 to 0.3 μm, from the point of increasing dispersibility and reflectance, It can also be used. The average particle diameter can be obtained by, for example, particle size distribution measurement by a laser light diffraction method.

  (D) It is preferable that the compounding quantity of a component is 2-50 mass parts with respect to a total of 100 mass parts of (A)-(C) component, More preferably, it is 3-40 mass parts, Most preferably, it is 3- 20 parts by mass. If the blending amount is too small, the desired reflectance may not be obtained. If the blending amount is too large, the viscosity may increase too much and the dispensing property may decrease.

The component (E) is a curing catalyst that promotes the reaction with the components (A) to (D), and is preferably an effective amount of a platinum group metal catalyst.
As this platinum group metal catalyst, any known hydrosilylation catalyst can be used. For example, platinum group metals such as platinum black, rhodium and palladium; H ₂ PtCl ₄ · dH ₂ O, H ₂ PtCl ₆ · dH ₂ O, NaHPtCl ₆ · dH ₂ O, KHPtCl ₆ · dH ₂ O, Na ₂ PtCl ₆ · dH ₂ O, K ₂ PtCl ₄ · dH ₂ O, PtCl ₄ · dH ₂ O, PtCl ₂ , Na ₂ HPtCl ₄ · dH ₂ O (wherein d is an integer of 0 to 6, preferably 0) Or chloroplatinic acid and chloroplatinate; alcohol-modified chloroplatinic acid (see US Pat. No. 3,220,972); complex of chloroplatinic acid and olefin (US patent) 3,159,601 specification, 3,159,662 specification, 3,775,452 specification); platinum group metals such as platinum black, palladium, etc., alumina, silica, carbon, etc. Supported on the carrier Rhodium-olefin complex; Chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst); Platinum chloride, chloroplatinic acid or chloroplatinate and vinyl group-containing siloxane, especially vinyl group-containing cyclic siloxane Can be mentioned. Among these, preferred are those obtained by modifying chloroplatinic acid with silicone from the viewpoint of compatibility and chlorine impurities. Specifically, for example, platinum obtained by modifying chloroplatinic acid with tetramethylvinyldisiloxane. A catalyst is mentioned.

  The addition amount of the curing catalyst may be a catalytic amount, but is preferably 1 to 500 ppm in terms of mass, more preferably 3 to 100 ppm in terms of the total of the components (A) to (D) as platinum atoms. Preferably it is 5-40 ppm.

  Various additives can be further added to the composition of the present invention as necessary. In particular, a hydrosilylation reaction inhibitor can be blended to improve storage stability when the composition of the present invention is used in a one-pack type. As the reaction inhibitor, conventionally known ones can be used. For example, an acetylene compound, a compound containing two or more alkenyl groups other than the component (A), a compound containing an alkynyl group, triallyl isocyanate, Examples thereof include nurate and derivatives thereof. Among these, it is desirable to use a compound having an alkenyl group or an alkynyl group. If the addition amount of these reaction inhibitors is too small, the effect of delaying the hydrosilylation reaction may not be obtained. Conversely, if too large, curing itself may be inhibited, so that (A) to (E) ) The total amount of the components is desirably in the range of 0.05 to 0.5 parts by mass with respect to 100 parts by mass. In order to further improve the heat resistance, hindered amines, hindered phenols, antioxidants, polymerization inhibitors, etc. may be added, and in order to further improve the adhesion, adhesion such as a silane coupling agent is imparted. An agent may be added.

  Examples of the method for producing the addition-curable silicone composition of the present invention include a method of mixing the components (A) to (E) and other optional components with a mixer such as a planetary mixer, a kneader, or a Shinagawa mixer.

  In the present invention, the viscosity and thixotropic coefficient of the composition are important factors for significantly improving workability. The viscosity of the composition at 25 ° C. when the rotational speed when using an E-type viscometer is 1 rpm is preferably 70 Pa · s or more and 500 Pa · s or less, and particularly preferably 100 to 350 Pa · s. If the viscosity is less than 70 Pa · s, the shape may not be maintained when dispensed or heat-cured, and if the viscosity is higher than 500 Pa · s, the material after dispensing may draw yarn or Since the material of the final part is poor, corners may stand up and the appearance may be poor. Further, the ratio of the viscosity at 1 rpm to the viscosity at 5 rpm (1 rpm / 5 rpm) (hereinafter referred to as a thixo coefficient) of the composition at 25 ° C. is 2.5 or more, particularly 2.5 to 4.5. preferable. If this thixotropic coefficient is less than 2.5, it may be difficult to stabilize the applied shape.

  The composition of the present invention uses a weak interaction (pseudo-crosslinking) between hydrogenpolysiloxane having an alkoxysilyl group and silanol on fumed silica, and has a high thixotropy while having low viscosity. The height / width ratio can be maintained at 0.8 or more, and the shape stability can be improved, without losing the shape both at the time of dispensing application (before curing) and after heat curing.

  When the composition of the present invention is used in a one-pack type, it is usually preferable to fill the syringe and store it.

  The curing conditions for the composition of the present invention are preferably heat-cured, and are usually cured at 80 to 200 ° C, preferably 100 to 150 ° C. The curing time may be appropriately selected depending on the shape of the molded product, the curing temperature, etc., but is usually 1 minute to 10 hours, preferably about 10 minutes to 4 hours.

  The method of curing the obtained composition is not limited, but, for example, a circle or a square line is drawn with the present composition using a dispensing device around an optical semiconductor element arranged on a substrate such as FRP resin. The white dam-shaped molded product is obtained by curing at 120 ° C. for 1 hour. A silicone sealing material is potted there and heated and cured to obtain an integrally molded product of the substrate, the white dam and the silicone sealing material according to the present invention. For those having high shape retention, it is possible to pot the silicone sealing material after application of the composition and heat cure the composition / sealing material in a lump. In addition, the composition of the present invention can be drawn in two or more layers to give a height.

  Here, the sealing material is not particularly limited, such as a silicone-based sealing agent and an epoxy-based sealing agent, but the silicone-based sealing material has adhesiveness with the composition of the present invention, stability over time (discoloration) after sealing. Is preferable). Among silicone-based sealants, an addition reaction curable silicone sealant which is the same curing method as the composition of the present invention is particularly preferable because it does not inhibit curing of the composition of the present invention.

  Examples of the sealing material include KER-2500A / B (manufactured by Shin-Etsu Chemical) made of dimethylpolysiloxane and KER-6000A / B (manufactured by Shin-Etsu Chemical) whose refractive index is increased to 1.5.

  The sealing material may or may not contain a phosphor depending on the type of LED element to be mounted. Further, fumed silica may be contained for the purpose of preventing sedimentation of the phosphor.

  Since the composition of the present invention also fulfills a function as a so-called reflector, it is preferable that the light reflectance of a cured product having a thickness of 2 mm has a high light reflectance of 90% or more, particularly 95% or more at 450 nm light. By reflecting light emitted from the semiconductor element with an excellent reflectance, it has a function of efficiently extracting light to the outside.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example. In the examples and comparative examples, the viscosity is a value measured with an E-type viscometer (RE80 manufactured by Toki Sangyo Co., Ltd.) at 25 ° C.

[Examples 1 to 3, Comparative Examples 1 to 4]
The components shown below were uniformly mixed with the universal mixing stirrer (Shinagawa mixer) manufactured by Dalton Co., Ltd. in the blending amounts shown in Table 1, to prepare a silicone composition.

〔Ｂ−２〕下記式で示される、アルコキシシリル基含有オルガノハイドロジェンポリシロキサン

〔Ｃ〕ＢＥＴ法による比表面積が２００ｍ²／ｇの煙霧質シリカ表面をヘキサメチルジシラザンで処理した表面処理煙霧質シリカ
〔Ｄ〕平均粒径０．１５μｍの酸化チタン粉末（石原産業（株）製）
〔Ｅ〕塩化白金酸から誘導した、テトラメチルビニルジシロキサンを配位子として有する白金触媒（白金原子量：１質量％）
〔反応制御剤〕エチニルヘキサノール
〔ハイドロジェンポリシロキサンＸ〕一分子中アルコキシシリル基を有しない、２５℃における粘度が５ｍＰａ．ｓで、水素ガス発生量が３３０ｍｌ／ｇであるメチルハイドロジェンポリシロキサン
〔結晶性シリカ〕（（株）龍森製：クリスタライト５Ｘ ＢＥＴ比表面積約５ｍ²／ｇ） [A] It has two vinyl groups directly bonded to silicon atoms in one molecule and has a viscosity of 10,000 mPa.s. organopolysiloxane (s) (80 parts by mass of organopolysiloxane having vinyl directly bonded to silicon atoms at both ends of the molecule and a viscosity at 25 ° C. of 5,000 mPa.s, Me ₃ SiO _1/2 , ViMe ₂ SiO _{1 /} 2 (Me the methyl group, Vi represents a vinyl group. hereinafter the same.), and is composed of SiO _4/2 units, Me against SiO _{4/2 3} SiO _1/2 and ViMe ₂ SiO _{1 /} A mixture of 20 parts by mass of a silicone resin in which the molar ratio of ₂ is 0.8 and the vinyl group content relative to the solid content is 0.085 mol / 100 g)
[B-1] It has a trimethoxysilylethyl group directly bonded to a silicon atom at one end in the molecule represented by the following formula and has a viscosity at 25 ° C. of 12 mPa.s. s, an alkoxysilyl group-containing organohydrogenpolysiloxane having a hydrogen gas generation rate of 70 ml / g

[B-2] An alkoxysilyl group-containing organohydrogenpolysiloxane represented by the following formula

[C] Surface-treated fumed silica obtained by treating the surface of fumed silica with a specific surface area of 200 m ² / g by BET method with hexamethyldisilazane [D] Titanium oxide powder with an average particle size of 0.15 μm (Ishihara Sangyo Co., Ltd.) Made)
[E] A platinum catalyst derived from chloroplatinic acid and having tetramethylvinyldisiloxane as a ligand (platinum atom weight: 1% by mass)
[Reaction Control Agent] Ethynylhexanol [Hydrogen Polysiloxane X] One molecule has no alkoxysilyl group and a viscosity at 25 ° C. of 5 mPa.s. methyl hydrogen polysiloxane [crystalline silica] with a hydrogen gas generation rate of 330 ml / g (made by Tatsumori Co., Ltd .: Crystallite 5X BET specific surface area of about 5 m ² / g)

Each physical property of the obtained composition was evaluated by the methods shown below. The results are also shown in Table 1.
[viscosity]
The viscosity at 25 ° C. at a rotation speed of 1 rpm and 5 rpm was measured with an E-type viscometer RE80 viscometer manufactured by Toki Sangyo Co., Ltd. Moreover, the thixo coefficient (1 rpm / 5 rpm) was calculated | required from these results.

[Shape stability (height / width aspect ratio)]
Using a dispenser manufactured by Musashi Engineering Co., Ltd., the line width was set to 0.8 mm and the height was set to 0.8 mm, and the line was drawn. About the line of the composition, the value of height / width before curing and when oven-cured at 120 ° C./1 hour is obtained, respectively, 0.8 or more is indicated by ◎, 0.6 or more and less than 0.8 by ○, Less than 6 was set as x.

[Light reflectance]
Measurement was performed using a spectrophotometer U-3310 manufactured by Hitachi, Ltd. and a φ60 integrating sphere attachment device. The sheet thickness of the composition was 2 mm, and the relative light reflectance of 450 nm light was measured using an attached aluminum oxide plate as a blank (100%).

[Adhesiveness]
Between 2 pieces of epoxy glass (width 2.5 cm, length 5 cm) made by Test Piece, placed so that the composition becomes 2.5 cm × 1 cm × 2 mm in thickness, and after oven-curing at 120 ° C./1 hour, Shear adhesion was measured. Further, the cohesive failure rate (CF) at this time was measured. In the table, TCF indicates the interface peeling rate.

From the results of Table 1, according to the present invention, a composition having high shape stability and high light reflectance even after heat curing can be obtained, and the composition can be used as a light reflecting material or a reflector of an optical semiconductor device. It is. In particular, those having a high shape-retaining property can be applied by overlapping the composition in two or three steps.
Further, according to the present invention, the lighting part (bright part) can have a degree of freedom. For example, a small circular or heart-shaped part can be described with a small number of LED chips.

Claims (6)

(A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass
(B) Organohydrogenpolysiloxane having hydrogen atoms bonded to at least two silicon atoms and at least one alkoxy group in one molecule: the total number of Si-H groups relative to the total number of alkenyl groups in the component (A) Is 1.4 to 5.0 times,
(C) Smokeous silica: 8 to 30 parts by mass with respect to a total of 100 parts by mass of components (A) and (B),
(D) a white pigment,
(E) A self-adhesive addition-curable silicone composition for an optical semiconductor device containing a curing catalyst.   When using an E-type viscometer, the viscosity at 25 ° C. when the rotational speed is 1 rpm is 70 Pa · s to 500 Pa · s, and the ratio to the viscosity at 25 rpm (25 ° C.) (1 rpm / 5 rpm viscosity ratio (thixo 2. The silicone composition according to claim 1, wherein the coefficient)) is 2.5 or more.   The silicone composition according to claim 1 or 2, wherein a ratio of height / width before and after curing of the silicone composition applied from a needle to a substrate by a dispensing device is 0.8 or more. object.   The silicone composition according to any one of claims 1 to 3, wherein a sheet obtained by molding and curing the addition-curable silicone composition with a thickness of 2 mm has a light reflectivity of 450 nm light of 90% or more.   A height of 0 for preventing the uncured liquid sealing material from flowing out by the silicone composition according to any one of claims 1 to 4 using a dispensing device on the substrate of the optical semiconductor device. A step of forming a dam of 5 mm or more, a step of heat-curing the dam of the silicone composition, if necessary, a step of potting a sealing material in the dam, and a curing of the dam of the sealing material or the silicone composition If not, a method for manufacturing an optical semiconductor device comprising the step of integrally forming the sealing material by heat-curing the sealing material.   An optical semiconductor device obtained by the method according to claim 5.