Addition-curable silicone composition, cured product thereof, and optical semiconductor device

Abstract

The present invention is an addition-curable silicone composition containing components (A) to (C): (A) An addition reaction product of an organopolysiloxane represented by formula (1) and a compound represented by formula (2), the addition reaction product having two addition-reactive carbon-carbon double bonds per molecule. (1) (R1 is a C1-12 monovalent hydrocarbon group, R2 is a methyl group or a phenyl group, a is an integer of 0-50, and b is an integer of 0-300. ), (2) (R3 represents a C1-12 divalent hydrocarbon group.), (B) an organosilicon compound having a hydrogen atom bonded to at least two silicon atoms per molecule, and (C) a hydrosilylation reaction catalyst. Thus, provided are an addition-curable silicone composition that has high transparency and a high refractive index and yields a cured product having high strength and high elongation and a highly reliable optical semiconductor device sealed by a cured product thereof.

Description

Addition-curable silicone composition, cured product thereof, and optical semiconductor device

[0001] The present invention relates to an addition-curable silicone composition, a cured product thereof, and an optical semiconductor device using the cured product.

[0002] Devices having light-emitting diodes (LEDs) as optical semiconductor elements are generally constructed by encapsulating the LEDs mounted on a substrate with a transparent resin encapsulant. Silicone resin compositions have attracted attention as encapsulants due to their heat resistance and heat-resistant discoloration. Addition-reaction-curable silicone resin compositions are highly productive because they can be cured in a short time by heating, and are therefore used as encapsulants for LEDs. Silicone encapsulants used in optical applications require high transparency and a high refractive index. Therefore, phenylmethylsilicone oil is commonly used (see Patent Documents 1 and 2). Conventional technologies have had problems with achieving high strength and high elongation while maintaining transparency. Therefore, improvements in rubber properties are needed to improve durability, such as crack resistance, in LED packages.

[0003] JP 2004-143361 A JP 2004-186168 A

[0004] The present invention has been made to solve the above problems, and has as its object to provide an addition-curable silicone composition that has high transparency and a high refractive index and that gives a cured product with high strength and elongation, and a highly reliable optical semiconductor device that is encapsulated with the cured product.

[0005] In order to solve the above problems, the present invention provides the following addition-curable silicone composition.

[0006] An addition-curable silicone composition characterized by containing the following components (A) to (C): (A) an addition reaction product of an organopolysiloxane represented by the following formula (1) and a compound represented by the following formula (2), the addition reaction product having two addition-reactive carbon-carbon double bonds in each molecule: (In the formula, R １are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, R ２ is a methyl group or a phenyl group, a is an integer of 0 to 50, and b is an integer of 0 to 300. However, when a is 0, R ２ is a phenyl group, and b is an integer of 1 to 300. The siloxane units in the parentheses followed by a and the siloxane units in the parentheses followed by b may be arranged randomly, in blocks, or alternately. (In the formula, R ３ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms and having no addition-reactive carbon-carbon double bond; (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule and having no addition-reactive carbon-carbon double bond-containing group, epoxy group, alkoxysilyl group, or carboxylic acid anhydride group; (C) a hydrosilylation reaction catalyst.

[0007] Such an addition-curable silicone composition can give a cured product that has high transparency and a high refractive index, as well as high strength and elongation.

[0008] In the component (A), R １ is a methyl group or a phenyl group, and R ２ is preferably a methyl group or a phenyl group.

[0009] Such an addition-curable silicone composition as component (A) has excellent transparency and a high refractive index, and also gives a cured product with high strength and elongation.

[0010] The addition-curable silicone composition of the present invention preferably contains, as component (D), an organopolysiloxane resin represented by the following formula (3): (R ４ ３ SiO １ / ２ ) ｃ (R ５ R ４ ２ SiO １ / ２ ) ｄ (R ４ ２ SiO ２ / ２ ) ｅ(R ５ R ４ SiO ２ / ２ ) ｆ (R ４ SiO ３ / ２ ) ｇ (R ５ SiO ３ / ２ ) ｈ (SiO ４ / ２ ) ｉ (3) (wherein, R ４ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, provided that R ４ 10 mol % or more of R are aryl groups having 6 to 12 carbon atoms, ５ is an alkenyl group having 2 to 12 carbon atoms, and c, d, e, f, g, h, and i are numbers that satisfy c≧0, d≧0, e≧0, f≧0, g≧0, h≧0, and i≧0, with the proviso that d+f+h>0, g+h+i>0, and c+d+e+f+g+h+i=1.

[0011] A composition containing such component (D) can give a cured product with even greater mechanical strength.

[0012] The addition-curable silicone composition of the present invention preferably contains, as component (E), an organopolysiloxane represented by formula (1).

[0013] A composition containing such component (E) can give a cured product that has an excellent balance of high strength and high elongation.

[0014] The present invention provides a cured product obtained by curing any of the addition-curable silicone compositions described above.

[0015] Such a cured product will have excellent strength and elongation.

[0016] An optical semiconductor device is provided in which an optical semiconductor element is encapsulated with the above-described cured product.

[0017] The cured product of the present invention has high strength and elongation. Therefore, an optical semiconductor device in which an optical semiconductor element is encapsulated with such a cured product is highly reliable and less susceptible to defects such as cracks.

[0018] As described above, the addition-curable silicone composition of the present invention provides a cured product that has high transparency and a high refractive index, as well as high strength and elongation. Therefore, the cured product derived from the addition-curable silicone composition of the present invention has high resistance to cracking and excellent adhesion to substrates, making it suitable for use as an encapsulating material for optical semiconductor elements such as LED elements.

[0019] The present invention will be described in detail below, but the present invention is not limited thereto.

[0020] As described above, there has been a need for the development of an addition-curable silicone composition that provides a cured product having high transparency and a high refractive index, as well as high mechanical strength and elongation, and for the development of a highly reliable optical semiconductor device in which an optical semiconductor element is encapsulated with the cured product.

[0021] As a result of extensive research into the above-mentioned problems, the present inventors discovered that an addition-curable silicone composition containing components (A), (B), and (C), which will be described below, could solve the above-mentioned problems, and thus completed the present invention.

[0022] That is, the present invention is an addition-curable silicone composition containing the following components (A), (B), and (C): The present invention is explained in detail below, but is not limited thereto.

[0023] [Addition-Curable Silicone Composition] The present invention provides an addition-curable silicone composition characterized by containing the following components (A) to (C): (A) an addition reaction product of an organopolysiloxane represented by the following formula (1) and a compound represented by the following formula (2), which has two addition-reactive carbon-carbon double bonds in each molecule: (In the formula, R １ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, R ２ is a methyl group or a phenyl group, a is an integer of 0 to 50, and b is an integer of 0 to 300. However, when a is 0, R ２is a phenyl group, and b is an integer of 1 to 300. The siloxane units in the parentheses followed by a and the siloxane units in the parentheses followed by b may be arranged randomly, in blocks, or alternately. (In the formula, R ３ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms and having no addition-reactive carbon-carbon double bond; (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule and having no addition-reactive carbon-carbon double bond-containing group, epoxy group, alkoxysilyl group, or carboxylic acid anhydride group; (C) a hydrosilylation reaction catalyst.

[0024] Each component will be described in detail below.

[0025] <Component (A)> Component (A) is an addition reaction product of an organopolysiloxane represented by formula (1) below and a compound represented by formula (2) below, and is an addition reaction product having two addition-reactive carbon-carbon double bonds per molecule.

[0026] (In the formula, R １ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, R ２ is a methyl group or a phenyl group, a is an integer of 0 to 50, and b is an integer of 0 to 300. However, when a is 0, R ２ is a phenyl group, and b is an integer of 1 to 300. The siloxane units in the parentheses followed by a and the siloxane units in the parentheses followed by b may be arranged randomly, in blocks, or alternately.

[0027] In formula (1), R １are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond. Specific examples thereof include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, cyclopentyl, and cyclohexyl groups; aryl groups having 6 to 12 carbon atoms, such as phenyl and naphthyl groups; alkylaryl groups having 7 to 12 carbon atoms, such as tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, and hexylphenyl groups; and aralkyl groups having 7 to 12 carbon atoms, such as benzyl and phenethyl groups. Among these, alkyl groups having 1 to 6 carbon atoms and phenyl groups are preferred, with methyl and phenyl groups being particularly preferred.

[0028] In formula (1), R 2 is a methyl group or a phenyl group.

[0029] a is preferably an integer of 1 to 30, more preferably an integer of 1 to 20, and even more preferably an integer of 2 to 10. b is preferably an integer of 0 to 100, more preferably an integer of 1 to 50, and even more preferably an integer of 2 to 30. If a exceeds 50, this is not preferable in terms of the heat discoloration resistance of the resulting cured product. Furthermore, if b exceeds 300, this is not preferable because the increased viscosity may reduce workability.

[0030] (In the formula, R ３ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond.

[0031] In formula (2), R ３Specific examples of the divalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond include linear, branched, or cyclic alkylene groups having 1 to 12 carbon atoms, such as methylene, ethylene, propylene, trimethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decamethylene; arylene groups having 6 to 12 carbon atoms, such as phenylene, biphenylene, and naphthylene; and aralkylene groups having 7 to 12 carbon atoms, such as phenylenemethylene and methylenephenylenemethylene. Of these, arylene groups having 6 to 12 carbon atoms are preferred, and phenylene groups are more preferred.

[0032] Specific examples of component (A) include, but are not limited to, those represented by the following formula: where Me represents a methyl group and Ph represents a phenyl group (the same applies hereinafter). (In the formula, the siloxane units in the parentheses may be arranged in any order.)

[0033] The component (A) may be used alone or in combination of two or more.

[0034] The viscosity of component (A) at 25°C measured with a rotational viscometer is preferably in the range of 1,000 to 1,000,000 mPa·s, and more preferably 50,000 to 500,000 mPa·s. A viscosity of component (A) in this range is preferred from the standpoint of workability.

[0035] <Component (B)> Component (B) is an organosilicon compound that has at least two, and preferably 2 to 100, silicon-bonded hydrogen atoms (SiH groups) per molecule, and that does not contain any addition-reactive carbon-carbon double bond-containing groups, epoxy groups, alkoxysilyl groups, or carboxylic acid anhydride groups. It acts as a crosslinking agent that crosslinks via a hydrosilylation reaction with the addition-reactive carbon-carbon double bonds contained in component (A) and components (D) and (E), which will be described later.

[0036] Substituents other than hydrogen atoms bonded to silicon atoms in component (B) include substituted or unsubstituted monovalent hydrocarbon groups that do not contain aliphatic unsaturated bonds, with substituted or unsubstituted monovalent hydrocarbon groups having 1 to 8 carbon atoms being preferred. Specific examples include alkyl groups such as methyl, ethyl, propyl, and butyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl and phenylethyl; and halogenated hydrocarbon groups such as chloromethyl, chloropropyl, and chlorocyclohexyl, with methyl and phenyl being particularly preferred.

[0037] The organosilicon compound of component (B) may be an organohydrogenpolysiloxane represented by the following formula (4) or a cyclic organohydrogensiloxane derivative represented by the following formula (5). (In the formula, R １ and R ２ is R in formula (1). １ and R ２ where j is an integer of 0 to 50, and k is an integer of 0 to 100. The arrangement of the siloxane units in the parentheses to which j and k are attached may be random, alternating, or block.

[0038] (In the formula, R 6 is a divalent group represented by the following formula (6), where p is independently 0 or 1, and q is an integer from 1 to 5.

[0039] (In the formula, an asterisk (*) represents a bond between adjacent silicon atoms.) The viscosity of component (B) at 25°C, as measured with a rotational viscometer, is preferably in the range of 1 to 3,000 mPa s, and more preferably 5 to 2,000 mPa s. A viscosity of component (B) within this range is preferred from the standpoint of workability.

[0040] Specific examples of the component (B) are shown below, but are not limited to these. (In the above formula, the siloxane units in parentheses may be arranged in any order.)

[0041] The component (B) may be used alone or in combination of two or more types.

[0042] The amount of component (B) blended is preferably 1 to 50 parts by mass, and more preferably 5 to 30 parts by mass, per 100 parts by mass of the total of component (A) and components (D) and (E) described below. Furthermore, the amount is preferably such that the total number of hydrogen atoms bonded to silicon atoms (SiH groups) in component (B) and component (F) described below is 0.5 to 5.0, and more preferably 0.7 to 3.0, per addition-reactive carbon-carbon double bond contained in components (A), (D), and (E). When the blending amount of component (B) satisfies this range, high mechanical strength can be imparted to the resulting cured product.

[0043] <Component (C)> The hydrosilylation catalyst for component (C) is not particularly limited, as long as it promotes the addition reaction between the addition-reactive carbon-carbon double bonds contained in component (A) and components (D) and (E) described below and the hydrogen atoms bonded to silicon atoms in components (B) and (F). Specific examples include platinum group metals such as platinum, palladium, and rhodium; platinum-based compounds such as chloroplatinic acid, alcohol-modified chloroplatinic acid, and coordination compounds of chloroplatinic acid with olefins, vinylsiloxanes, or acetylene compounds; and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium and chlorotris(triphenylphosphine)rhodium. Component (C) is preferably a platinum-based compound, and particularly preferably a coordination compound of chloroplatinic acid with vinylsiloxane.

[0044] The component (C) may use either a single compound or a combination of two or more compounds.

[0045] The amount of component (C) added may be an effective catalytic amount, preferably in the range of 0.1 to 1000 ppm, and more preferably in the range of 1 to 500 ppm, calculated as platinum group metal mass relative to the total amount of components (A), (D), and (E). When this range is satisfied, the reaction rate of the addition reaction becomes appropriate, and a cured product with high strength can be obtained.

[0046] <Component (D)> The addition-curable silicone composition of the present invention may contain, as component (D), an organopolysiloxane resin having silicon-bonded alkenyl groups, in order to improve the mechanical strength of the cured product.

[0047] The component (D) is preferably an organopolysiloxane resin represented by the following formula (3): (R ４ ３ SiO １ / ２ ) ｃ (R ５ R ４ ２ SiO １ / ２ ) ｄ (R ４ ２ SiO ２ / ２ ) ｅ (R ５ R ４ SiO ２ / ２ ) ｆ (R ４ SiO ３ / ２ ) ｇ (R ５ SiO ３ / ２ ) ｈ (SiO ４ / ２ ) ｉ (3) (wherein, R ４ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, provided that R ４ 10 mol % or more of R are aryl groups having 6 to 12 carbon atoms, ５ is an alkenyl group having 2 to 12 carbon atoms, and c, d, e, f, g, h, and i are numbers that satisfy c≧0, d≧0, e≧0, f≧0, g≧0, h≧0, and i≧0, provided that d+f+h>0, g+h+i>0, and c+d+e+f+g+h+i=1.) In the above formula (3), all R ４ Among them, 10 mol % or more, preferably 20 mol % or more, are aryl groups having 6 to 12 carbon atoms. The presence of aryl groups can improve the refractive index, improve the light extraction efficiency in optical semiconductor devices, and impart gas barrier properties, etc. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, and naphthyl groups, with phenyl being particularly preferred.

[0048] The above R ４ In the formula (I), the groups other than the aryl group are not particularly limited as long as they are substituted or unsubstituted monovalent hydrocarbon groups that do not contain alkenyl groups, and examples thereof include unsubstituted or halogen-substituted monovalent hydrocarbon groups typically having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, such as alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups. A methyl group is particularly preferred.

[0049] The above R ５ Examples of the alkenyl group include alkenyl groups having 2 to 10 carbon atoms, preferably 2 to 6 carbon atoms, such as vinyl, allyl, and ethynyl groups, with vinyl being particularly preferred.

[0050] In component (D), the content of silicon-bonded alkenyl groups is preferably in the range of 0.01 to 1 mol, and more preferably 0.1 to 0.6 mol, per 100 g of component (D). When the content of the alkenyl groups is in the range of 0.01 to 1 mol, the crosslinking reaction proceeds sufficiently, resulting in a cured product with higher hardness.

[0051] In the above formula (3), g, h, and i are numbers that satisfy g+h+i>0 (i.e., a branched structure is essential), but are preferably numbers that satisfy 0.05≦g+h+i≦0.9, and more preferably numbers that satisfy 0.1≦g+h+i≦0.7.

[0052] Specific examples of the organopolysiloxane resin of component (D) include the following:

[0053] [(CH ３ ) ３ SiO １／２ ] ０．３ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．１ [(C ６ H ５ ) ２ SiO２／２ ] ０．４５ [SiO ４／２ ] ０．１５

[0054] [(CH ２ =CH)(CH ３ ) (C ６ H ５ ) SiO １／２ ] ０．２ [(C ６ H ５ ) ２ SiO ２／２ ] ０．３５ [SiO ４／２ ] ０．４５

[0055] [(CH ２ =CH)(CH ３ ) (C ６ H ５ ) SiO １／２ ] ０．１３ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．２９ [(C ６ H ５ ) ２ SiO ２／２ ] ０．０５ [SiO ４／２ ] ０．５３

[0056] The component (D) may use either a single compound or a combination of two or more compounds.

[0057] The organopolysiloxane resin of component (D) is preferably a wax or solid at 25°C, for ease of isolation.

[0058] When component (D) is used, the blending amount is preferably in the range of 1 to 50 mass %, more preferably in the range of 5 to 40 mass %, based on the total mass of component (A), component (D), and component (E) described below, from the viewpoint of the hardness and adhesiveness of the resulting cured product.

[0059] <Component (E)> The addition-curable silicone composition of the present invention may contain, as component (E), an organopolysiloxane represented by the following formula (1): This component is the same as the organopolysiloxane listed above as the component represented by formula (1) in (A). (In the formula, R １ , R ２ , a, b are R in the above formula (1). １ , R ２ The siloxane units in the parentheses marked with a and the siloxane units in the parentheses marked with b may be arranged randomly, in blocks, or alternately.

[0060] When component (E) is used, its amount is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, based on the total mass of components (A), (D), and (E). Having component (E) in this range is advantageous in terms of the strength and extensibility of the resulting cured product. <Component (F)> The addition-curable silicone composition of the present invention may contain an adhesion promoter as component (F) to improve adhesion to substrates. The adhesion promoter is a compound containing one or more functional groups selected from the group consisting of an addition-reactive carbon-carbon double bond-containing group, an epoxy group, an alkoxysilyl group, and a carboxylic acid anhydride group. Component (F) is distinguished from component (B) in that it contains the above functional groups.

[0061] Specific examples of the component (F) include vinyltrimethoxysilane (trade name: KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidyloxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 8-glycidyloxyoctyltrimethoxysilane (trade name: KBM-4803, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (trade name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-trimethoxysilylpropylsuccinic anhydride (trade name: X-12-967C, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0062] Additionally, organosilicon compounds represented by the following structural formulas can also be suitably used as component F.

[0063] Furthermore, silicon-free adhesion promoters can also be used, specific examples of which include allyl glycidyl ether, vinylcyclohexene monoxide, diethyl 2-allylmalonate, allyl benzoate, diallyl phthalate, tetraallyl pyromellitic acid ester (trade name: TRIAM 805, Wako Pure Chemical Industries, Ltd.), and triallyl isocyanurate.

[0064] The component (F) may be used alone or in combination of two or more types.

[0065] When component (F) is used, the blending amount is preferably 0.05 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, per 100 parts by mass of the combined total of components (A), (D), and (E). A blending amount of component (F) within this range is preferable in terms of adhesion to substrates, strength, and extensibility of the resulting cured product.

[0066] <Other Components> In addition to the components (A) to (F) described above, the addition-curable silicone composition of the present invention may also contain other components, such as those exemplified below.

[0067] (Reaction Inhibitor) A reaction inhibitor may be added to the composition of the present invention in order to adjust the curing rate.

[0068] Examples of reaction inhibitors include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; sulfur-containing compounds; acetylene compounds; hydroperoxy compounds; maleic acid derivatives; 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and ethynylmethyldecylcarbinol.

[0069] Since the degree of curing inhibition effect of the reaction inhibitor varies depending on the chemical structure of the reaction inhibitor, it is desirable to adjust the amount of the reaction inhibitor to an optimal amount for each reaction inhibitor used. Preferably, the amount is 0.001 to 5 parts by mass per 100 parts by mass of the total of the above components (A), (D), and (E). If the amount is 0.001 part by mass or more, the long-term storage stability of the composition at room temperature can be sufficiently obtained. If the amount is 5 parts by mass or less, there is no risk of inhibiting the curing of the composition.

[0070] (Antioxidant) An antioxidant may be added to the composition of the present invention to prevent discoloration over time. Examples of antioxidants include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), and bissebacate(1,2,2,6,6-pentamethyl-4-piperidine). These may be used alone or in combination of two or more.

[0071] When an antioxidant is used, its amount is not particularly limited as long as it is an effective amount as an antioxidant, but it is usually preferably blended in an amount of about 1 to 10,000 ppm, and particularly about 10 to 1,000 ppm, based on the total mass of the above components (A), (D), and (E). By blending in an amount within this range, the antioxidant ability is fully exerted, and a cured product with excellent optical properties is obtained without the occurrence of coloration, cloudiness, oxidative degradation, etc.

[0072] (Light Stabilizer) A light stabilizer may be added to the composition of the present invention to impart resistance to degradation due to light energy from sunlight, fluorescent lamps, and the like. Hindered amine stabilizers that capture radicals generated by photooxidative degradation are suitable as light stabilizers, and their antioxidant effect is further improved by using them in combination with an antioxidant. Specific examples of light stabilizers include bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, and 4-benzoyl-2,2,6,6-tetramethylpiperidine.

[0073] When a light stabilizer is used, its amount is not particularly limited as long as it is an effective amount as a light stabilizer, but it is usually preferably blended in an amount of about 1 to 10,000 ppm, and particularly about 10 to 1,000 ppm, based on the total mass of the above components (A), (D), and (E). By blending in an amount within this range, the antioxidant ability is fully exerted, and a cured product with excellent optical properties is obtained without the occurrence of coloration, cloudiness, oxidative degradation, etc.

[0074] (Filler) In addition to fumed silica, the composition of the present invention may further contain inorganic fillers such as crystalline silica, hollow silica, titanium oxide, alumina, and fillers obtained by subjecting the surface of these fillers to hydrophobic treatment with an organosilicon compound such as an organoalkoxysilane compound, an organochlorosilane compound, an organosilazane compound, or a low-molecular-weight siloxane compound; silicone rubber powder, silicone resin powder, and the like.

[0075] The filler should have a specific surface area (BET method) of 50 m from the viewpoint of imparting thixotropy to the composition of the present invention and reinforcing properties to the cured product. ２ / g or more, and more preferably 50 to 400m ２ / g, particularly preferably 100 to 300m ２ / g.

[0076] It is also preferable to use fillers that have been treated with organosilicon compounds such as methylchlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane, and methyltrichlorosilane, dimethylpolysiloxane, and hexaorganodisilazanes such as hexamethyldisilazane, divinyltetramethyldisilazane, and dimethyltetravinyldisilazane.

[0077] Examples of such fillers include Reolosil DM30 (manufactured by Tokuyama Corporation), Aerosil NSX-200 (manufactured by Nippon Aerosil Co., Ltd.), and Musil 120A (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0078] When a filler is used, the blending amount is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the total of the above components (A), (D), and (E). Within this range, sedimentation of the fumed silica in the composition can be suppressed, and sufficient reinforcement can be obtained. Furthermore, there is no risk of imparting excessive thixotropy, which would reduce workability.

[0079] The viscosity of the addition-curable silicone composition of the present invention, as measured with a rotational viscometer, is preferably 0.1 to 50 Pa s, and more preferably 1 to 10 Pa s, at 25° C. If the viscosity of the addition-curable silicone composition of the present invention is within this range, this is preferable in terms of workability when sealing semiconductor devices.

[0080] [Cured Product] The present invention also provides a cured product (cured silicone product) obtained by curing the addition-curable silicone composition.

[0081] The addition-curable silicone composition of the present invention can be cured under known conditions, for example, at 60 to 180° C. for 10 minutes to 5 hours.

[0082] The cured product of the addition-curable silicone composition of the present invention has high strength and elongation, and is less susceptible to defects such as cracking, making it useful as an encapsulant for optical semiconductor devices and the like.

[0083] [Optical semiconductor device] The present invention further provides an optical semiconductor device in which an optical semiconductor element is encapsulated with the above-described cured product. Examples of optical semiconductor elements (optical elements) that can be encapsulated with an encapsulant made of the composition of the present invention include LEDs, semiconductor lasers, photodiodes, phototransistors, solar cells, and CCDs. Such optical elements can be encapsulated by applying an encapsulating material made of the composition of the present invention to the optical element and curing the applied encapsulating material by a known curing method under known curing conditions, specifically as described above.

[0084] The present invention will be described in more detail below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. In the following examples, Me represents a methyl group, Ph represents a phenyl group, and the viscosity is a value measured at 25°C using a rotational viscometer.

[0085] Synthesis Example 1 Synthesis of Component (A-1) 409 g of an organopolysiloxane represented by formula (7) below (vinyl group amount: 0.22 mol / 100 g) and 450 g of toluene were placed in a 1 L four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, and the mixture was heated to 85°C using an oil bath. 0.09 g of a toluene solution (platinum concentration: 0.5% by mass) of a reaction product of platinum hexachloride and 1,3-divinyltetramethyldisiloxane was added thereto, and 43.8 g (0.225 mol) of 1,4-bis(dimethylsilyl)benzene, a compound represented by formula (2), was added dropwise over 20 minutes with stirring. After completion of the dropwise addition, the mixture was stirred at 100°C for 3 hours and then cooled to 25°C. Thereafter, 2.3 g of activated carbon was added, and the mixture was stirred for 1 hour. After that, the mixture was filtered and then evaporated under reduced pressure to obtain 450 g of a colorless and transparent addition reaction product (A-1, viscosity at 25°C: 282,000 mPa s) represented by the following formula (8):

[0086] Synthesis Example 2 Synthesis of Component (A-2) 2100 g of an organopolysiloxane represented by formula (9) below (vinyl group amount: 0.103 mol / 100 g) and 2100 g of toluene were placed in a 5 L four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, and the mixture was heated to 85°C using an oil bath. 0.7 g of a toluene solution (platinum concentration: 0.5% by mass) of a reaction product of platinum hexachloride and 1,3-divinyltetramethyldisiloxane was added thereto, and 181 g of 1,4-bis(dimethylsilyl)benzene, a compound represented by formula (2), was added dropwise over 30 minutes with stirring. After completion of the dropwise addition, the mixture was heated and stirred at 95°C for 3 hours and then cooled to room temperature. Thereafter, 23 g of activated carbon was added, and the mixture was stirred for 1 hour, followed by filtration and concentration under reduced pressure to obtain 2,200 g of a colorless and transparent addition reaction product (A-2, viscosity at 25°C: 90,000 mPa s) represented by the following formula (10):

[0087] (In the formula, the order of the siloxane units in parentheses is not specified.) (In the formula, the order of the siloxane units in the parentheses is not specified.) (In the formula, n is a number that results in the above viscosity, and the order of the siloxane units in the parentheses is not specified.)

[0088] Examples 1 to 3, Comparative Examples 1 to 3 Addition-curable silicone compositions were prepared by mixing the following components in the amounts shown in Table 1. The numerical values ​​for each component in Table 1 represent parts by mass.

[0089] Component (A): (A-1) the addition reaction product obtained in Synthesis Example 1 (A-2) the addition reaction product obtained in Synthesis Example 2

[0090] Component (B): (B-1) an organohydrogenpolysiloxane represented by the following formula (11): (In the formula, the order of the siloxane units in parentheses is not specified.) (B-2) Organohydrogenpolysiloxane represented by the following formula (12):

[0091] (B-3) A cyclic organohydrogensiloxane derivative represented by the following formula (13): Component (C): (C-1) a catalyst (platinum concentration 1% by mass) prepared by diluting the reaction product of platinum hexachloride and 1,3-divinyltetramethyldisiloxane with an organopolysiloxane represented by the following formula (14): (In the formula, the order of the siloxane units in parentheses is not specified.)

[0092] Component (D): (D-1) a silicone resin represented by the following formula (15):

[0093] Component (E): (E-1) a linear organopolysiloxane represented by the formula (7) above; (E-2) a linear organopolysiloxane represented by the formula (14) above; and (E-3) a linear organopolysiloxane represented by the following formula (16): (In the formula, the order of the siloxane units in parentheses is not specified.)

[0094] (E-4) A linear organopolysiloxane represented by the following formula (17): (In the formula, the order of the siloxane units in parentheses is not specified.)

[0095] Component (F): Adhesion aid (F-1) Cyclic organohydrogensiloxane represented by the following formula (18): (F-2) 8-glycidyloxyoctyltrimethoxysilane (trade name: KBM-4803, manufactured by Shin-Etsu Chemical Co., Ltd.) (F-3) A compound represented by the following formula (19):

[0096] Other components: (G-1) Reaction inhibitor: ethynylmethyldecylcarbinol (H-1) Light stabilizer: Tinuvin 292 (manufactured by BASF Japan) (I-1) Silicone resin represented by the following formula (20):

[0097]

[0098] Each composition was evaluated as follows, and the results are shown in Table 2. (Appearance) The appearance was determined by visually inspecting the composition for cloudiness. Those without cloudiness were rated as passing. (Refractive Index) The refractive index for 589 nm light was measured at 25°C using an ATAGO RX-5000 digital refractometer. Those with a refractive index of 1.45 or higher were rated as passing. (Film Strength) Each composition was heated at 150°C for 2 hours, molded into a 2 mm thick sheet, and cured. The film strength was measured using a No. 2 dumbbell in accordance with JIS-K6249:2003. (Hardness) A hardness of 30 or higher was rated as passing. (Elongation at Break) An elongation at break of 50% or higher was rated as passing. (Tensile Strength) A tensile strength of 1.0 or higher was rated as passing.

[0099]

[0100] As shown in Table 2, the addition-curable silicone compositions of Examples 1 to 3 of the present invention had high transparency and a high refractive index, and the cured products made from these compositions had high strength and high elongation. On the other hand, in Comparative Example 1, which did not use component (A), an essential component of the present invention, and instead used component (E-2), the cured product had low strength and low elongation. In Comparative Example 2, which used component (E-3) instead, the composition became cloudy and the cured product had low elongation. Furthermore, in Comparative Example 3, which used a combination of component (E-4) and the silicone resin component (I-1) instead of component (A), the cured product had good physical properties, but the appearance was cloudy and the refractive index was low.

[0101] This specification includes the following inventions.

[0102] [1]: An addition-curable silicone composition characterized by containing the following components (A) to (C): (A) an addition reaction product of an organopolysiloxane represented by the following formula (1) and a compound represented by the following formula (2), the addition reaction product having two addition-reactive carbon-carbon double bonds in each molecule; (In the formula, R １ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, R ２is a methyl group or a phenyl group, a is an integer of 0 to 50, and b is an integer of 0 to 300. However, when a is 0, R ２ is a phenyl group, and b is an integer of 1 to 300. The siloxane units in the parentheses followed by a and the siloxane units in the parentheses followed by b may be arranged randomly, in blocks, or alternately. (In the formula, R ３ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond; (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms per molecule and no addition-reactive carbon-carbon double bond-containing group, epoxy group, alkoxysilyl group, or carboxylic acid anhydride group; (C) a hydrosilylation reaction catalyst. [2]: In the component (A), R １ is a methyl group or a phenyl group, and R ２ is a methyl group or a phenyl group. [3]: The addition-curable silicone composition according to [1] or [2], characterized in that it contains, as component (D), an organopolysiloxane resin represented by the following formula (3): (R ４ ３ SiO １ / ２ ) ｃ (R ５ R ４ ２ SiO １ / ２ ) ｄ (R ４ ２ SiO ２ / ２ ) ｅ (R ５ R ４ SiO ２ / ２ ) ｆ (R ４ SiO ３ / ２ ) ｇ (R ５ SiO ３ / ２ ) ｈ (SiO ４ / ２ ) ｉ (3) (wherein, R ４ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, provided that R４ 10 mol % or more of R are aryl groups having 6 to 12 carbon atoms, ５ is an alkenyl group having 2 to 12 carbon atoms, and c, d, e, f, g, h, and i are numbers that satisfy c≧0, d≧0, e≧0, f≧0, g≧0, h≧0, and i≧0, with the proviso that d+f+h>0, g+h+i>0, and c+d+e+f+g+h+i=1. (4) The addition-curable silicone composition according to any one of (1) to (3), which contains, as component (E), an organopolysiloxane represented by formula (1). (5) A cured product obtained by curing the addition-curable silicone composition according to any one of (1) to (4). (6) An optical semiconductor device, which comprises an optical semiconductor element encapsulated with the cured product according to (5).

[0103] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. An addition-curable silicone composition characterized by containing the following components (A) to (C): (A) an addition reaction product between an organopolysiloxane represented by the following formula (1) and a compound represented by the following formula (2), the addition reaction product having two addition-reactive carbon-carbon double bonds in each molecule; (In the formula, R １ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, R ２ is a methyl group or a phenyl group, a is an integer of 0 to 50, and b is an integer of 0 to 300. However, when a is 0, R ２ is a phenyl group, and b is an integer of 1 to 300. The siloxane units in the parentheses followed by a and the siloxane units in the parentheses followed by b may be arranged randomly, in blocks, or alternately. (In the formula, R ３ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms and having no addition-reactive carbon-carbon double bond; (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule and having no addition-reactive carbon-carbon double bond-containing group, epoxy group, alkoxysilyl group, or carboxylic acid anhydride group; (C) a hydrosilylation reaction catalyst.

2. In the component (A), R １ is a methyl group or a phenyl group, and R ２ 2. The addition-curable silicone composition according to claim 1, wherein is a methyl group or a phenyl group.

3. The addition-curable silicone composition according to claim 1, characterized in that it contains, as component (D), an organopolysiloxane resin represented by the following formula (3): (R ４ ３ SiO １ / ２ ) ｃ (R ５ R ４ ２ SiO １ / ２ ) ｄ (R ４ ２ SiO ２ / ２ ) ｅ (R ５ R ４ SiO ２ / ２ ) ｆ (R ４ SiO ３ / ２ ) ｇ (R ５ SiO ３ / ２ ) ｈ (SiO ４ / ２ ) ｉ (3) (wherein, R ４ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no addition-reactive carbon-carbon double bond, provided that R ４ 10 mol % or more of R are aryl groups having 6 to 12 carbon atoms, ５ is an alkenyl group having 2 to 12 carbon atoms, and c, d, e, f, g, h, and i are numbers that satisfy c≧0, d≧0, e≧0, f≧0, g≧0, h≧0, and i≧0, with the proviso that d+f+h>0, g+h+i>0, and c+d+e+f+g+h+i=1.

4. The addition-curable silicone composition according to claim 1, characterized in that it contains, as component (E), an organopolysiloxane represented by formula (1).

5. A cured product characterized by being obtained by curing the addition-curable silicone composition according to any one of claims 1 to 4.

6. An optical semiconductor device, characterized in that an optical semiconductor element is encapsulated with the cured product according to claim 5.

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