Butyl Rubbers : Butyl rubbers are a type of synthetic rubber prepared by polymerization of butylenes. They are a preferred option in the manufacture of automobile tires thanks to their leak-proof qualities.
The Association of Petrochemicals Producers in Europe (APPE), The European petrochemical industry, Glossary of Terms on Chemical Safety for Use in IPCS Publications, van Nieuwenhuyse, Brussels 2006. http://www.petrochemistry.eu/glossary.html, (Petrochem Ind - Brit) {473}