Patent ID: 7750171

Claim:
A process for preparing a hydrosilylation-crosslinkable one-component silicone composition comprising at least one polyorganosiloxane (POS) A bearing ethylenic and/or acetylenic unsaturation(s), at least one polyorganohydrosiloxane (POS) B, a hydrosilylation catalyst and an inhibitor which is an organophosphorus compound inhibiting the action of the catalyst at room temperature, said process comprising premixing said hydrosilylation catalyst and said inhibitor to form a catalyst/inhibitor additive and then combining said additive with said at least one polyorganosiloxane (POS) A bearing ethylenic and/or acetylenic unsaturation(s) and said at least one polyorganohydrosiloxane (POS) B, wherein said inhibitor is of the following formula (I): in which: R, R 1 , R 2 , R 3 and R 4 , which are identical or different, represent a linear, branched or cyclic alkyl radical or an aryl or alkylaryl radical which is substituted or unsubstituted; or wherein the inhibitor is of formula (VIII) P(OR) 3 in which R is an alkylaryl radical having 7 to 31 carbon atoms, wherein the premixing to form the catalyst/inhibitor additive is carried out by mixing the inhibitor in a silicone gum or oil at a temperature greater than the melting temperature or softening temperature of the inhibitor, followed by cooling, followed by addition of the catalyst.