design guide

Isobutylene Isoprene Rubber (IIR)

Butyl is a common term used for the isobutylene isoprene elastomer. As the name implies, butyl is comprised of isobutylene with a small amount of isoprene. It is known for its excellent resistance to water, steam, alkalis, and oxygenated solvents. Another outstanding characteristic is low gas permeation. Butyl is capable of providing high-energy absorption (dampening) and good hot tear strength.

Good resistance to heat, abrasion, oxygen, ozone and sunlight are dependent upon the butyl polymer saturation level. Butyl however, displays poor resistance to petroleum oil, gasoline and hydrocarbon solvents.

Compounds 487KC, 487KD, 487KE, 487KF

  • Very low outgassing
  • Excellent vibration dampening compounds
  • Low extractables

Compounds 359DQ, 501C, 359DN

  • Good acid and base resistance
  • Weather and high temperature resistant
Compound Hardness
Shore A
Tensile Elongation
MPa psi
359DQ 60 8.3 1200 400
501C 70 13.8 2000 320
359DN 80 8.3 1200 370
487KC 40 9.0 1300 850
487KD 50 9.0 1300 650
487KE 60 9.7 1400 420
487KF 70 8.3 1200 300