Description: Rubber made from butyl is actually a blend of polymers mixed with a little bit of isoprene.  Butyl Rubber is a very good general purpose rubber for many applications. The chemical resistance of Butyl Rubber is good, the rubber holds up well in most industrial applications. 
The most unique characteristic of Butyl rubber is that its permeability to air is 70% better than that of most other rubber materials and for this reason the industry uses it for tire tubes and tubeless tire inner liners.  Butyl Rubber can be used in so many applications it is hard to list them all.

Using Butyl rubber as a substitute for a cheap neoprene is common in marine environments.  Butyl Rubber is sometimes called SBR rubber or iso rubber.