Room temperature-vulcanizing silicone caulk

Room-temperature vulcanizing silicone rubbers (RTV) are also available commercially and are used as adhesives, caulks, and coatings [67]. The RTV systems usually improve the reaction of silanols with ethyl silicate catalyzed by tin compounds (dibutyltin dilaurate) to eliminate ethyl alcohol with the formation of the resin [Eq. (29)]. The time required for the final cure is about an hour at 150°C or 24 hr at room temperature. 

Special grades of silicone (called RTV or room temperature vulcanization) are used by the caulking industry. Silicone is also used by the adhesives industry. 

RTV silicone adhesive is a rubberlike polymer called polydimethsiloxane. RTV stands for room temperature vulcanizing, or simply a rubber that cures at room temperature. Silicone rubber adhesives are made using a complicated process that turns elemental silicon metal made from sand (silica) into a rubbery polymer. When cured, silicone rubber adhesives/sealants have excellent resistance to heat (500—600 °F) and moisture that makes them exceptionally suited for outdoor weathering applications such as sealant and caulking compounds in the construction industry. Because of its exceptional properties, silicone adhesive has been used in some exotic applications such as the soles of the boots worn by the first astronauts to walk on the moon. Silicone adhesive/sealants are used to seal windows, doors, and portholes on the space shuttle and many satellite missiles. A special silicone adhesive is used to bond the heat shield tiles on space shuttles. 

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