Butyl rubber is an elastomeric polymer that is used in a wide variety of adhesives and sealants. Because of its unique properties it also is used in the automotive and food processing industries among others. Butyl sealants can be applied in a number of different forms. It is used widely as a hot melt, solvent solution, preformed tape or gasket, and as a gun-dispensable sealant. Butyl rubber can be used as a primary base resin or as an additive for tack and other desired properties.
RESULTING PROPERTIES
Butyl rubber sealants can be formulated as well as caulks and extruded tapes. Noncuring butyl sealants with no solvent have long life if used between building panels and in sound deadening applications. They do not harden or oxidize and are not affected by weather.
A caulk formulation is shown above. The table shows a comparison using cellulose fibers and fumed silica to replace asbestos in a butyl caulk. Note that a certain percentage of fumed silica is still required in the cellulose fiber filled formulations for optimal non-sag properties. The cellulose fibers’ low specific gravity (1.1) relative to other filler materials also contribute to weight savings that further improves the sag resistance of these systems.
