Butyl rubber, also known as Isobutylene-isoprene (IIR), is a synthetic elastomer produced by low temperature cationic copolymerization of 1,1-dimethylethylene (isobutylene) with about 0.5 to 2 percent 1-methyl-1-butenylene (isoprene) using Lewis catalysts in chlorocarbon solvents. The isoprene provides the necessary unsaturation sites for crosslinking (vulcanization).
● Butyl rubber has unique elastomeric properties that makes it a good choice for a wide variety of rubber goods.
● Its low gas permeability together with its flexibility makes it the ideal material for inner tubes of tires and other high pressure tubes.
● Other applications include diaphragms, gaskets, wire and cable insulations, liners, O-rings, seals, weather stripping, and bottle closures.
● Its very low resilience makes it also suitable for shock absorption, vibration damping and insolation applications.
● Lower molecular grades find uses in pressure sensitive adhesives, hot melts, caulks, and sealants. Products formulated with butyl rubber have improved chemical and heat resistance.