Provided is a hydrosilylation reactive composition that has a sufficient pot life at room temperature, that can be cured at low temperature by exposure to high energy radiation, and that produces a stable semi-cured product during the curing process, and to provide a semi-cured product and a cured product obtained using this hydrosilylation reactive composition. The composition comprises: (A) a compound containing at least one aliphatically unsaturated monovalent hydrocarbon group in the molecule; (B) a compound containing at least two hydrogen atoms bonded to silicon atoms in the molecule; (C) a first hydrosilylation catalyst exhibiting activity in the composition without exposure to high energy radiation; and (D) a second hydrosilylation catalyst not exhibiting activity unless exposed to high energy radiation, and exhibiting activity in the composition by exposure to high energy radiation.

An object is to provide a heat conductive sheet having good handleability when mounting between the heating element and the heat dissipator, and softness that enables the distortion of the heating element, the heat dissipator, and the like to be suppressed in use. The heat conductive sheet contains: a matrix comprising a cured product of organopolysiloxane; and heat conductive fillers comprising anisotropic fillers with their major axes oriented in the thickness direction, and has a load property P represented b formula (1) below of 0.1 to 0.7: Load property P=(F.sub.30−F.sub.20)/F.sub.10 (1) wherein F.sub.10 is a load of the heat conductive sheet at 10% compression, F.sub.20 is a load of the heat conductive sheet at 20% compression, and F.sub.30 is a load of the heat conductive sheet at 30% compression.

Provided is a thermally conductive silicone composition that can be turned into a lightweight cured product superior in thermal conductivity, and is easily processable due to its low viscosity. The composition contains: (A) an organopolysiloxane having at least two alkenyl groups per each molecule; (B) an organohydrogenpolysiloxane having, per each molecule, at least two hydrogen atoms directly bonded to silicon atoms; (C) a thermally conductive filler containing magnesium oxide (20 to 40% by mass), aluminum oxide (40 to 60% by mass) and aluminum hydroxide (10 to 30% by mass); (D) a dimethylpolysiloxane with one end of the molecular chain thereof being blocked by a trialkoxy group; (E) a platinum group metal-based curing catalyst; and (F) an addition reaction control agent.

A process for modifying an expandable curing bladder for a tire, which bladder has a surface intended to come into contact with a tire casing is provided. The process comprises a step of applying to the surface a layer of a silicone rubber composition comprising a first liquid organopolysiloxane bearing chain-end alkenyl groups, a second liquid organohydropolysiloxane and a photoactivatable hydrosilylation catalyst, and a step of exposing the silicone rubber composition covering the surface to irradiation with ultraviolet-visible light.

Provided are rapidly cross-linkable silicone foam compositions, kits, and methods for filling implanted medical devices in situ or in vivo, the implanted medical devices, including for example, body implants and tissue expanders, the compositions including a platinum divinyl disiloxane complex; a low viscosity vinyl terminated polydimethylsiloxane; a low viscosity hydride terminated polydimethylsiloxane; a silicone cross-linker; and a gas and/or gas-filled microcapsules, where the rapidly cross-linkable silicone foam composition has a viscosity of ≤150 cPs for ≥1 min. post-preparation and ≤300 cPs≤5 min. post-preparation, at ambient temperature.

The present disclosure relates to a silicone rubber foam layer obtainable by a process that includes providing a substrate; providing a first solid film and applying it onto the substrate; providing a coating tool provided with an upstream side and a downstream side, wherein the coating tool is offset from the substrate to form a gap normal to the surface of the substrate; moving the first solid film relative to the coating tool in a downstream direction; providing a curable and foamable precursor of the silicone rubber foam to the upstream side of the coating tool thereby coating the precursor of the silicone rubber foam through the gap as a layer onto the substrate provided with the first solid film; providing a second solid film and applying it along the upstream side of the coating tool, such that the first solid film and the second solid film are applied simultaneously with the formation of the adjacent layer of the precursor of the silicone rubber foam; foaming or allowing the precursor of the silicone rubber foam to foam; curing or allowing the layer of the precursor of the silicone rubber foam to cure thereby forming the silicone rubber foam layer; optionally, exposing the layer of the precursor of the silicone rubber foam to a thermal treatment; and optionally, removing the first solid film and/or the second solid film from the silicone rubber foam layer.

This disclosure relates to continuous methods of making foamed silicone elastomers. This disclosure also relates to compositions used for forming foamed silicone elastomers. The compositions comprise: (i) an organopolysiloxane having at least two silicon-bonded unsaturated groups per molecule; (ii) an organohydrogensiloxane having at least two silicon-bonded hydrogen atoms per molecule; (iii) a hydrosilylation catalyst; and (iv) a physical blowing agent. Foamed silicone elastomers can be prepared from such compositions, using, for example, the methods disclosed herein.

A curable hot-melt silicone composition that is less susceptible to curing inhibition and with excellent storage stability, and a sheet or film containing the same, is provided. The composition comprises: (A) a solid organopolysiloxane resin containing a specific ratio of (A1) an organopolysiloxane resin having a curing reactive functional group that contains a carbon-carbon double bond and containing 20 mol % or more of a Q unit, and (A2) an organopolysiloxane resin not having a curing reactive functional group that contains a carbon-carbon double bond and containing 20 mol % or more of a Q unit; (B) a chain organopolysiloxane having a curing reactive functional group that contains at least two carbon-carbon double bonds; (C) an organohydrogenpolysiloxane resin having a mass loss ratio relative to pre-exposure of 10% or less after exposure to 100° C. for 1 hour under atmospheric pressure; and (D) a hydrosilylation reaction catalyst. The composition generally has hot-melt properties.

The present invention relates to a hardenable silicone composition including an irradiation-activated system for temporarily inhibiting the hydrosilylation reaction. Said system includes at least one inhibitor selected from among α-acetylenic alcohols, α-α′-acetylenic diesters, conjugated ene-yne compounds, α-acetylenic ketones, acrylonitriles, maleates, fumarates, the mixture thereof, at least one photoinitiator, and tris(trimethylsilyl)silane (TTMSS). The invention also relates to a method for preparing a silicone coating and hard elastomer materials provided comprising said silicone composition.

A crosslinked silicone material Y obtained by heating to a temperature of between 70 and 200° C., a crosslinkable composition X including an organopolysiloxane compound A containing, per molecule, at least two C.sub.2-C.sub.6 alkenyl radicals bonded to silicon atoms; an organohydrogenopolysiloxane compound B containing, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom; a catalyst C of formula [Ni(L.sup.1).sub.2] where Ni represents nickel at degree of oxidation II; L.sup.1 which may be identical or different, represents a β-dicarbonylato anion or the enolate anion of a β-dicarbonylated compound; optionally an adhesion promoter D; and optionally a charge E.