| abstract |
A method of producing a one-part silicone elastomeric sealant which has improved shelf life and an economical process of manufacture is disclosed. The method mixes a diorganovinylsiloxy endblocked polydiorganosiloxane, reinforcing filler, and a silazane. This reinforced base is then converted by reacting with a silane of the formula H[SiR2OSiR2CH2CH2]bSiRa(OR'')3-a where R is methyl, ethyl, propyl, phenyl or trifluoropropyl, R'' is methyl or ethyl, a is 0 or 1, and b is 0 or 1 using a platinum catalyst. The result is a base containing an alkoxy functional polymer. This base is then mixed with alkoxy functional silane crosslinker and titanium catalyst to yield a composition which is stable in the absence of moisture for long periods of time in storage, but cures to an elastomer upon exposure to moisture. The improved shelf life is due to the presence of alkylene radicals between the penultimate silicon atom and the last silicon atom of the polymer. |