Silicone gel composition and use thereof

Abstract

A silicone gel composition comprising: (A) branched organopolysiloxane having, on average, at least two alkenyl groups bonded to silicon atoms in a molecule, and a viscosity ranging from 10 to 10,000 mPa·s at 25° C.; (B) organohydrogenpolysiloxane; (C) platinum-based addition reaction catalyst; and (D) a reaction product of (d1) alkali metal silanolate with (d2) at least one ceric salt selected from cerium chloride and a carboxylic acid salt of cerium.

1 . A silicone gel composition comprising:
 (A) branched organopolysiloxane in an amount of 100 parts by mass, having, on average, at least two alkenyl groups bonded to silicon atoms in a molecule, and a viscosity ranging from 10 to 10,000 mPa·s at 25° C.;   (B) organohydrogenpolysiloxane in an amount so that an amount of hydrogen atoms bonded to silicon atoms is 0.7 to 1.2 per one alkenyl group bonded to silicon atom in a total amount of the composition, having at least two hydrogen atoms bonded to silicon atoms in a molecule, and a viscosity ranging from 2 to 1,000 mPa·s at 25° C.;   (C) a platinum-based addition reaction catalyst in an amount so that an amount of platinum-based metal is from 0.01 to 1,000 ppm in the total amount of the composition; and,   (D) a reaction product, in an amount of 0.2 to 10.0 parts by mass, of (d1) alkali metal silanolate with (d2) at least one ceric salt selected from cerium chloride and a carboxylic acid salt of cerium.   
     
     
         2 . The silicone gel composition according to  claim 1 , further comprising (A2) linear organopolysiloxane, in an amount of 2 to 150 parts by mass per 100 parts by mass of the component (A), having at least two alkenyl groups bonded to silicon atoms in a molecule, and a viscosity ranging from 1.0 to 10,000 mPa·s at 25° C. 
     
     
         3 . The silicone gel composition according to  claim 1 , wherein, among total siloxane units constituting the branched organopolysiloxane (A) molecule, from 80.0 to 99.8 mol % of the units are R 2 SiO 2/2  units, from 0.1 to 10.0 mol % of the units are RSiO 3/2  units, and from 0.1 to 10.0 mol % of the units are R 3 SiO 1/2  units, wherein all the R groups represent monovalent hydrocarbon groups bonded to a silicon atom. 
     
     
         4 . The silicone gel composition according to  claim 3 , wherein, in the total monovalent hydrocarbon groups bonded to the silicon atoms in the branched organopolysiloxane (A), from 0.25 to 4.00 mol %. 
     
     
         5 . The silicone gel composition according to  claim 1 , wherein the component (D) comprises from 0.5 to 5.0 mass % of cerium metal. 
     
     
         6 . The silicone gel composition according to  claim 1 , wherein the component (d1) is an alkali metal silanolate compound obtained by subjecting (d1-1) at least one cyclic organopolysiloxane to a ring opening reaction using (d1-2) an alkali metal hydroxide, and then subjecting the resulting product to a further reaction with (d1-3) organopolysiloxane having a viscosity ranging from 10 to 10,000 mPa·s at 25° C. 
     
     
         7 . The silicone gel composition according to  claim 1 , wherein the compounded amount of the component (D) is such that a content of cerium metals in the component (D) is from 0.005 to 0.15 mass % based on the total amount of the composition. 
     
     
         8 . A silicone gel-cured material which is produced by curing the silicone gel composition according to  claim 1 . 
     
     
         9 . The silicone gel-cured material according to  claim 8 , which is substantially transparent and has 10 to 150 of direct reading value of ¼ consistency defined by JIS K 2220. 
     
     
         10 . A sealant for an electronic component comprising the silicone gel composition according to  claim 1 . 
     
     
         11 . The sealant for an electronic component according to  claim 10 , which is substantially transparent. 
     
     
         12 . An electronic component having the silicone gel-cured material according to  claim 8 . 
     
     
         13 . The electronic component according to  claim 12 , which is a component of a power device. 
     
     
         14 . The electronic component according to  claim 13 , wherein the power device is a motor control, a motor control for a transport, a power generation system, or a space transportation system. 
     
     
         15 . A light-emitting semiconductor device having a light-emitting semiconductor element encapsulated by the silicone gel-cured material according to  claim 8 . 
     
     
         16 . A general lighting device, optical substrate, or photoelectric substrate having the silicone gel-cured material according to  claim 8 . 
     
     
         17 . A method for protecting semiconductor chips, wherein the semiconductor chips are sealed using the silicone gel composition according to  claim 1 . 
     
     
         18 . A method for protecting semiconductor chips, wherein the silicone gel-cured material according to  claim 8  seals the semiconductor chips.