Abstract: A hydrosilylation reaction-curable organopolysiloxane composition comprising (A) a methylpheny-lalkenylpolysiloxane that has at least two alkenyl groups wherein diphenylsiloxane units are no more than 5 mole % and at least 20 mole % is comprised of phenyl groups, (B) a methylphenylhydrogenpolysiloxane that has at least two Si-bonded hydrogen atoms wherein diphenylsiloxane units are no more than 5 mole % and at least 20 mole % is comprised of phenyl groups, and (C) a hydrosilylation reaction catalyst. An optical semiconductor element sealant comprising this composition. An optical semiconductor device sealed with this optical semiconductor element sealant.

Abstract: A curable organopolysiloxane composition and an optical semiconductor element sealant, each comprising (A) a diorganopolysiloxane that has at least 2 alkenyl groups wherein at least 70 mole % of all the siloxane units are methylphenylsiloxane units and the total content of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane is no more than 5 weight %, (B) an organopolysiloxane that has at least 2 silicon-bonded hydrogen atoms wherein at least 15 mole % of the silicon-bonded organic groups are phenyl groups, and (C) a hydrosilylation reaction catalyst. An optical semiconductor device in which an optical semiconductor element within a housing is sealed with the cured product from the aforementioned composition.

Abstract: A curable organopolysiloxane composition comprising: (A) an organopolysiloxane that contains in one molecule at least two alkenyl groups and at least 30 mole % of all silicon-bonded monovalent hydrocarbon groups in the form of aryl groups: (B) an organopolysiloxane that contains in one molecule at least two silicon-bonded hydrogen atoms and at least 15 mole % of all silicon-bonded organic groups in the form of aryl groups; (C) a branched-chain organopolysiloxane that contains alkenyl, aryl, and epoxy-containing organic groups; and (D) a hydrosilylation catalyst. The composition is capable of forming a cured body that has a high index of refraction and strong adhesion to substrates.

Abstract: A composition includes: (I) an alkenyl functional, phenyl-containing polyorganosiloxane, an Si—H functional phenyl-containing polyorganosiloxane, or a combination thereof; (II) a hydrogendiorganosiloxy terminated oligodiphenylsiloxane having specific molecular weight, an alkenyl-functional, diorganosiloxy-terminated oligodiphenylsiloxane having specific molecular weight, or a combination thereof; and (III) a hydrosilylation catalyst. A light emitting device is made by applying the composition onto a light source followed by curing. The composition provides a cured material with mechanical properties suited for use as an encapsulant for a light emitting device.

Abstract: An optical device of the present invention comprises a light-emitting element or a light-receiving element mounted on a support and a cured silicone material unified into a single article onto the support by the sealing of the element with a hydrosilylation reaction curable silicone composition, and is characterized in that the surface of the cured silicone material has been treated with an organopolysiloxane that has at least three silicon-bonded hydrogen atoms in one molecule. The optical device is resistant to the adherence of dust and dirt due to an inhibition of the stickiness of the surface of a cured silicone material that seals a light-emitting element or a light-receiving element mounted on a support and has thereby been unified into a single body onto the support.

Abstract: A curable organopolysiloxane composition comprises at least the following components: an organopolysiloxane (A) represented by the following general formula: R13SiO(R12SiO)mSiR13 (where R1 is a monovalent hydrocarbon group, and “m” is an integer from 0 to 100); an organopolysiloxane (B) represented by the following average unit formula: (R2SiO3/2)a(R22SiO2/2)b(R23SiO1/2)c (where R2 is a monovalent hydrocarbon group, and “a”, “b”, and “c” are specific numbers); an organopolysiloxane (C) having in one molecule on average at least two silicon-bonded aryl groups and on average at least two silicon-bonded hydrogen atoms; and a hydrosilylation-reaction catalyst (D); is characterized by good fillability and curability and that, when cured, forms a cured body that possesses a high refractive index, high light transmissivity, and strong adhesion to various substrates.

Abstract: A hydrosilylation reaction-curable organopolysiloxane composition comprising (A) a methylpheny-lalkenylpolysiloxane that has at least two alkenyl groups wherein diphenylsiloxane units are no more than 5 mole % and at least 20 mole % is comprised of phenyl groups, (B) a methylphenylhydrogenpolysiloxane that has at least two Si-bonded hydrogen atoms wherein diphenylsiloxane units are no more than 5 mole % and at least 20 mole 1% is comprised of phenyl groups, and (C) a hydrosilylation reaction catalyst. An optical semiconductor element sealant comprising this composition. An optical semiconductor device sealed with this optical semiconductor element sealant.

Abstract: A curable organopolysiloxane composition and an optical semiconductor element sealant, each comprising (A) a diorganopolysiloxane that has at least 2 alkenyl groups wherein at least 70 mole % of all the siloxane units are methylphenylsiloxane units and the total content of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane is no more than 5 weight %, (B) an organopolysiloxane that has at least 2 silicon-bonded hydrogen atoms wherein at least 15 mole % of the silicon-bonded organic groups are phenyl groups, and (C) a hydrosilylation reaction catalyst. An optical semiconductor device in which an optical semiconductor element within a housing is sealed with the cured product from the aforementioned composition.

Abstract: A curable organopolysiloxane composition comprising: (A) an organopolysiloxane that contains in one molecule at least two alkenyl groups and at least 30 mole % of all silicon-bonded monovalent hydrocarbon groups in the form of aryl groups: (B) an organopolysiloxane that contains in one molecule at least two silicon-bonded hydrogen atoms and at least 15 mole % of all silicon-bonded organic groups in the form of aryl groups; (C) a branched-chain organopolysiloxane that contains alkenyl, aryl, and epoxy-containing organic groups; and (D) a hydrosilylation catalyst. The composition is capable of forming a cured body that has a high index of refraction and strong adhesion to substrates.

Abstract: A composition includes: (I) an alkenyl functional, phenyl-containing polyorganosiloxane, an Si—H functional phenyl-containing polyorganosiloxane, or a combination thereof; (II) a hydrogendiorganosiloxy terminated oligodiphenylsiloxane having specific molecular weight, an alkenyl-functional, diorganosiloxy-terminated oligodiphenylsiloxane having specific molecular weight, or a combination thereof; and (III) a hydrosilylation catalyst. A light emitting device is made by applying the composition onto a light source followed by curing. The composition provides a cured material with mechanical properties suited for use as an encapsulant for a light emitting device.

Abstract: A curable organopolysiloxane composition comprises at least the following components: an organopolysiloxane (A) represented by the following general formula: R13SiO(R12SiO)mSiR13 (where R1 is a monovalent hydrocarbon group, and “m” is an integer from 0 to 100); an organopolysiloxane (B) represented by the following average unit formula: (R2SiO3/2)a(R22SiO2/2)b(R23SiO1/2)c (where R2 is a monovalent hydrocarbon group, and “a”, “b”, and “c” are specific numbers); an organopolysiloxane (C) having in one molecule on average at least two silicon-bonded aryl groups and on average at least two silicon-bonded hydrogen atoms; and a hydrosilylation-reaction catalyst (D); is characterized by good fillability and curability and that, when cured, forms a cured body that possesses a high refractive index, high light transmissivity, and strong adhesion to various substrates.

Abstract: A curable organopolysiloxane composition comprising (A) a linear organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, (B) a branched organopolysiloxane having at least one alkenyl group and at least one aryl group per molecule, and having siloxane units represented by the general formula: RsiO2/3, (C) a linear organopolysiloxane with both terminal ends of the molecular chain blocked by silicon bonded hydrogen atoms having at least one aryl group per molecule, and (D) a hydrosilation reaction catalyst, and a semiconductor device whose semiconductor elements are coated with the cured product of the above-described composition. The curable organopolysiloxane composition shows low viscosity, excellent filling properties, and excellent curability that cures to form a soft cured product of a large refractive index, high light transmittance, and high adhesion to substrates, as well as the semiconductor device shows superior reliability.

Abstract: A curable organopolysiloxane composition comprising (A) a linear organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, (B) a branched organopolysiloxane having at least one alkenyl group and at least one aryl group per molecule, and having siloxane units represented by the general formula: RsiO2/3, (C) a linear organopolysiloxane with both terminal ends of the molecular chain blocked by silicon bonded hydrogen atoms having at least one aryl group per molecule, and (D) a hydrosilation reaction catalyst, and a semiconductor device whose semiconductor elements are coated with the cured product of the above-described composition. The curable organopolysiloxane composition shows low viscosity, excellent filling properties, and excellent curability that cures to form a soft cured product of a large refractive index, high light transmittance, and high adhesion to substrates, as well as the semiconductor device shows superior reliability.

Abstract: A silicone gel composition is characterized by excellent storage stability in a non-cured state and by high adhesion to a substrate and long-term stability of consistency at elevated temperatures after curing. The silicone gel composition comprises: a polyorganosiloxane (A), which consists of polyorganosiloxane (A-1) that contains R(CH3)2SiO2/2 units, RsiO3/2 units R(CH3)2SiO1/2 units, and polydiorganosiloxane (A-2) that contains R(CH3)2SiO2/2 units and R(CH3)2SiO1/2 units, and R(CH3) which contains in one molecule two silicon-bonded hydrogen atoms; an addition-reaction platinum catalyst (C); an organosilicon compound (D) selected from silane of the general formula (R1O)nSiR24-n or a partially hydrolyzed condensate thereof; and an organic titanium compound (E).

Abstract: A silicone gel composition is characterized by excellent storage stability in a non-cured state and by high adhesion to a substrate and long-term stability of consistency at elevated temperatures after curing. The silicone gel composition comprises: a polyorganosiloxane (A), which consists of polyorganosiloxane (A-1) that contains R(CH3)2SiO2/2 units, RsiO3/2 units, and R(CH3) 2SiO1/2 units, and polydiorganosiloxane (A-2) that contains R(CH3)2SiO2/2 units and R(CH3)2SiO1/2 units; a polyorganosiloxane (B), which contains in one molecule two silicon-bonded hydrogen atoms; an addition-reaction platinum catalyst (C); an organosilicon compound (D) selected from silane of the general formula (R1O)nSiR24-n or a partially hydrolyzed condensate thereof; and an organic titanium compound (E).