Abstract: The electrical properties, particularly contact resistance and volume resistivity, of materials prepared by curing organosiloxane compositions containing finely divided silver as the electroconductive filler are improved by treating the silver particles with an organosilicon compound prior to incorporating the particles into the organosiloxane composition.

Abstract: This invention is a process for making modified silica filler comprising the steps of: (A) contacting an acidic aqueous suspension of precipitated or colloidal silica, optionally in the presence of a surfactant and/or a water-miscible solvent, with a combination of (a) a functionalizing coupling agent, and (b) an organometallic hydrophobing compound in a weight ratio of (a) to (b) of at least 0.001 to 1 to form an acidic aqueous suspension of chemically treated silica filler having a pH of 2.0 or less (B) treating the acidic aqueous suspension of the chemically treated filler with an acid-neutralizing agent to increase the pH of the suspension to a range of from greater than 2.0 to 10, and (C) recovering the chemically treated filler. This invention is also modified silica filler that has a pH of from about 5.0 to 10.0, where the silica filler is made by the method of this invention.

Abstract: A thermally conductive silicone rubber composition, comprising (A) a curable organopolysiloxane (B) a curing agent; and (C) a filler prepared by treating the surface of a thermally conductive filler with an oligosiloxane having a formula selected from (i) (R1O)aSi(OSiR23)(4−a) and (ii) (R1O)aR2(3−a)SiO[R22SiO]nSi(OSiR23)bR2(3−b) wherein R1 is alkyl, each R2 is independently a monovalent hydrocarbon group free of aliphatic unsaturation, subscript a is an integer from 1 to 3, b is an integer from 1 to 3, and n is an integer having a value greater than or equal to 0.

Abstract: An oligosiloxane having the formula (R1O)aSi(OSiR22R3)4−a wherein R1 is alkyl; each R2 is independently selected from C1 to C10 monovalent hydrocarbyl free of aliphatic unsaturation; R3 is hydrocarbly free of aliphatic unsaturation and having at least 11 carbon atoms; and a is 1, 2, or 3; and a method of preparing an alkoxy-functional oligosiloxane.

Abstract: A curable silicone composition for preparing a silicone adhesive, the composition comprising (A) an organopolysiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule; (B) an organohydrogenpolysiloxane containing an average of at least two silicon-bonded hydrogen atoms per molecule in a concentration sufficient to cure the composition; (C) an electrically conductive filler in an amount sufficient to impart electrical conductivity to the silicone adhesive, wherein the filler comprises particles having at least an outer surface of a metal selected from silver, gold, platinum, palladium, and alloys thereof; (D) an effective amount of a hydroxy-functional organic compound having a molecular weight up to about 1000 and containing at least one hydroxy group per molecule, provided the compound is free of acetylenic hydroxy groups and the compound does not substantially inhibit cure of the composition; and (E) a catalytic amount of a hydrosilylation catalyst.