Full definition
Sheet produced from IIR (isobutylene-isoprene rubber/butyl rubber), offering the lowest gas permeability of any commercial rubber (8-10x lower than NR) combined with excellent vibration damping (rebound resilience 12-20%, the lowest of all rubbers). Thicknesses: 1.5-6 mm. Hardness: 40-75 Shore A. Temperature range: -45 to +120°C. Key properties: outstanding resistance to ozone, weathering, and many chemicals (dilute acids, alkalis, polar solvents); high electrical resistivity. Limitations: poor resistance to mineral oils and hydrocarbon solvents. Applications: gas-tight membranes and linings (chemical tanks, gas-sampling bags), vacuum sealing sheets (for composite autoclave bagging), sound deadening and vibration isolation panels (automotive, marine, architectural), pharmaceutical closures (bottle stoppers), and waterproof barriers. The high damping coefficient makes butyl sheet uniquely effective for noise and vibration control — a 2-3 mm butyl sheet bonded to a metal panel reduces vibration by 10-20 dB. Also available as chlorobutyl and bromobutyl for improved heat resistance and co-vulcanization compatibility. Per ASTM D2000 classification AA.