What butyl rubber it is

  Butyl rubber is one of the most widely used synthetic polymers in the world, ranking third in total synthetic elastomers used.
  First introduced in 1942, butyl rubber origins are due to the rubber-procurement program of the U.S. Government during World War II. This program sought to ensure the availability of rubber supplies for military use. Indeed, shortages of natural rubber during wartime have resulted in the development of many of today’s synthetic rubber compounds.