Abstract: A curable composition containing a curable liquid-form organopolysiloxane composition and a curable liquid-form organic resin composition. The organic resin composition is contained as liquid particles in the organopolysiloxane composition. A cured product formed by curing the abovementioned curable liquid composition such that the cured product contains fine particles of a cured organic resin in a cured organopolysiloxane matrix. An electronic part which is covered by the cured product of the abovementioned curable liquid-form composition.

Abstract: A process for the production of organopentasiloxane represented by the general formula: ##STR1## wherein R.sup.1 is an acryloyloxy-containing monovalent organic group or a methacryloyloxy-containing monovalent organic group; R.sup.3 is a monovalent hydrocarbon group; X is a hydrolytic group; and the subscript n is 0, 1, or 2; which is characterized subjecting (A) 1-hydroxy-organotetrasiloxane, or an organosiloxane oligomer mixture comprising it as the main component, which is obtained by hydrolyzing 1-acyloxy-organotetrasiloxane or an oganosiloxane oligomer mixture comprising it as the main component; and (B) hydrolytic silane represented by the general formula R.sup.3.sub.n SiX.sub.(4-n) to a condensation reaction.

Abstract: A curable organosiloxane composition useable as a silicone die attach adhesive, an electrically conductive silicone rubber composition each comprising a composition that cures through both addition and condensation reactions, that will not impair wire bondability to a semiconductor chip or lead frame after the semiconductor chip has been bonded to a substrate or package; and semiconductor devices in which the semiconductor chip is bonded to its substrate or package using the curable organosiloxane composition and in which the semiconductor device that evidences high reliability by virtue of the use of the curable organosiloxane composition.

Abstract: A microparticle catalyst for hydrosilylation reactions which contains microparticles of an average particle diameter of 0.1 to 20 .mu.m made of a metallic catalyst for hydrosilylation reactions; a disiloxane having the general formula (R.sup.1 R.sup.2 ArSi).sub.2 O, wherein, R.sup.1 is an alkenyl group, R.sup.2 is a monovalent hydrocarbon group and Ar is an aryl group; and a resin having a glass transition temperature of 40.degree. to 200.degree. C. and thermosetting silicone composition containing the microparticle catalyst.

Abstract: A mixture of carbonyl iron powder and a silicone resin containing silica siloxane units and silanol groups can be stabilized for storage by mixing a stabilizing amount of an halosilane with the mixture; monochlorosilanes are preferred. The small amount of halosilane that is needed can be further reduced by vacuuming the mixture before adding the halosilane. The stabilized compositions are useful as reactive components in curable silicone mixtures.

Abstract: Radar attenuating compositions comprising a low viscosity siloxane polymer, a resinous crosslinker therefor and carbonyl iron powder have improved thermal stability when exposed to temperatures as high as 450.degree. F. The particular crosslinker that is used in the compositions of this invention provides improved stability for the compositions at room temperature storage conditions and also in the cured form. The compositions can be sprayed and/or molded and cured at room temperature and/or elevated temperatures, as desired.

Abstract: Cross-liked resins exhibiting a high level of optical transparency and little variation of refractive index with temperature are prepared using mixtures of two organosiloxane resins in combination with a reinforcing silica filler. The types and relative concentrations of hydrocarbon radicals in the resins are within specified limits to obtain the required optical properties and each resin contains groups that react with groups on the other resin to form a crosslinked network.