Method of adjusting physical properties in silicone elastomeric sealant

摘要

An improved silicone elastomeric sealant composition is produced by mixing alkoxy functional polydiorganosiloxane having alkoxysilethylene ends with a combination of trifunctional or tetrafunctional silane crosslinker and defunctional silane chain extender. The sealant composition is stable upon storage in the absence of moisture, but cures to an elastomer upon exposure to moisture. The cured composition can be adjusted for the desired elongation by varying the ratio of crosslinker to chain extender, but there must be at least 50 mol percent of crosslinker in the composition to ensure that the composition cures to a non-tacky surface.